STM31961205

STM31961205
STM32F051xx
ARM-based 32-bit MCU, 16 to 64-KB Flash, timers, ADC,
DAC and communication interfaces, 2.0-3.6 V
Datasheet  production data
Features
F
 Core: ARM® 32-bit Cortex™-M0 CPU,
frequency up to 48 MHz
 Memories
– 16 to 64 Kbytes of Flash memory
– 8 Kbytes of SRAM with HW parity checking
 CRC calculation unit
 Reset and power management
– Voltage range: 2.0 V to 3.6 V
– Power-on/Power down reset (POR/PDR)
– Programmable voltage detector (PVD)
– Low power modes: Sleep, Stop, Standby
– VBAT supply for RTC and backup registers
 Clock management
– 4 to 32 MHz crystal oscillator
– 32 kHz oscillator for RTC with calibration
– Internal 8 MHz RC with x6 PLL option
– Internal 40 kHz RC oscillator
 Up to 55 fast I/Os
– All mappable on external interrupt vectors
– Up to 36 I/Os with 5 V tolerant capability
 5-channel DMA controller
 1 x 12-bit, 1.0 μs ADC (up to 16 channels)
– Conversion range: 0 to 3.6 V
– Separate analog supply from 2.4 up to 3.6
 One 12-bit D/A converter
 Two fast low-power analog comparators with
programmable input and output
 Up to 18 capacitive sensing channels
supporting touchkey, linear and rotary touch
sensors
 Up to 11 timers
– One 16-bit 7-channel advanced-control
timer for 6 channels PWM output, with
deadtime generation and emergency stop
– One 32-bit and one 16-bit timer, with up to
4 IC/OC, usable for IR control decoding
January 2014
This is information on a product in full production.
LQFP64 10x10 mm
LQFP48 7x7 mm
LQFP32 7x7 mm
UFQFPN32
5x5 mm
UFQFPN48
7x7 mm
A
UFBGA64
5x5 mm
– One 16-bit timer, with 2 IC/OC, 1 OCN,
deadtime generation and emergency stop
– Two 16-bit timers, each with IC/OC and
OCN, deadtime generation, emergency
stop and modulator gate for IR control
– One 16-bit timer with 1 IC/OC
– Independent and system watchdog timers
– SysTick timer: 24-bit downcounter
– One 16-bit basic timer to drive the DAC
 Calendar RTC with alarm and periodic wakeup
from Stop/Standby
 Communication interfaces
– Up to 2 I2C interfaces; one supporting Fast
Mode Plus (1 Mbit/s) with 20 mA current
sink, SMBus/PMBus and wakeup from STOP
– Up to two USARTs supporting master
synchronous SPI and modem control; one
with ISO7816 interface, LIN, IrDA
capability, auto baud rate detection and
wakeup feature
– Up to two SPIs (18 Mbit/s) with 4 to 16
programmable bit frame, 1 with I2S
interface multiplexed
 HDMI CEC interface, wakeup on header
reception
 Serial wire debug (SWD)
 96-bit unique ID
®
 All packages ECOPACK 2
Table 1. Device summary
Reference
STM32F051xx
DocID022265 Rev 4
Part number
STM32F051K4, STM32F051C4, STM32F051R4
STM32F051K6, STM32F051C6, STM32F051R6
STM32F051C8, STM32F051R8, STM32F051K8
1/115
www.st.com
Contents
STM32F051xx
Contents
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3
Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1
ARM® CortexTM-M0 core with embedded Flash and SRAM . . . . . . . . . 12
3.2
Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3
Boot modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4
Cyclic redundancy check calculation unit (CRC) . . . . . . . . . . . . . . . . . . . 13
3.5
Power management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Power supply schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5.2
Power supply supervisors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5.3
Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5.4
Low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.6
Clocks and startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.7
General-purpose inputs/outputs (GPIOs) . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.8
Direct memory access controller (DMA) . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.9
Interrupts and events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.10
2/115
3.5.1
3.9.1
Nested vectored interrupt controller (NVIC) . . . . . . . . . . . . . . . . . . . . . . 16
3.9.2
Extended interrupt/event controller (EXTI) . . . . . . . . . . . . . . . . . . . . . . 16
Analog to digital converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.10.1
Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.10.2
Internal voltage reference (VREFINT) . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.10.3
VBAT battery voltage monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.11
Digital-to-analog converter (DAC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.12
Comparators (COMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.13
Touch sensing controller (TSC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.14
Timers and watchdogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.14.1
Advanced-control timer (TIM1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.14.2
General-purpose timers (TIM2..3, TIM14..17) . . . . . . . . . . . . . . . . . . . . 21
3.14.3
Basic timer TIM6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.14.4
Independent watchdog (IWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.14.5
System window watchdog (WWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
DocID022265 Rev 4
STM32F051xx
Contents
3.14.6
SysTick timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.15
Real-time clock (RTC) and backup registers . . . . . . . . . . . . . . . . . . . . . . 22
3.16
Inter-integrated circuit interfaces (I2C) . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.17
Universal synchronous/asynchronous receiver transmitters (USART) . . 24
3.18
Serial peripheral interface (SPI)/Inter-integrated sound interfaces (I2S) . 25
3.19
High-definition multimedia interface (HDMI) - consumer
electronics control (CEC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.20
Serial wire debug port (SW-DP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4
Pinouts and pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5
Memory mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
6
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1
Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.1
Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.2
Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.3
Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.4
Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.5
Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
6.1.6
Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6.1.7
Current consumption measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6.2
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6.3
Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.3.1
General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.3.2
Operating conditions at power-up / power-down . . . . . . . . . . . . . . . . . . 47
6.3.3
Embedded reset and power control block characteristics . . . . . . . . . . . 47
6.3.4
Embedded reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.3.5
Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.3.6
Wakeup time from low-power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
6.3.7
External clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
6.3.8
Internal clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.3.9
PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.3.10
Memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.3.11
EMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.3.12
Electrical sensitivity characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.3.13
I/O current injection characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
DocID022265 Rev 4
3/115
4
Contents
7
STM32F051xx
6.3.14
I/O port characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.3.15
NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.3.16
12-bit ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.3.17
DAC electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.3.18
Comparator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6.3.19
Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
6.3.20
VBAT monitoring characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
6.3.21
Timer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.3.22
Communication interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Package characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7.1
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7.2
Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
7.2.1
Reference document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
7.2.2
Selecting the product temperature range . . . . . . . . . . . . . . . . . . . . . . 108
8
Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4/115
DocID022265 Rev 4
STM32F051xx
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Table 21.
Table 22.
Table 23.
Table 24.
Table 25.
Table 26.
Table 27.
Table 28.
Table 29.
Table 30.
Table 31.
Table 32.
Table 33.
Table 34.
Table 35.
Table 36.
Table 37.
Table 38.
Table 39.
Table 40.
Table 41.
Table 42.
Table 43.
Table 44.
Table 45.
Table 46.
Table 47.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
STM32F051xx family device features and peripheral counts . . . . . . . . . . . . . . . . . . . . . . . 10
Temperature sensor calibration values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Internal voltage reference calibration values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Capacitive sensing GPIOs available on STM32F051xx devices . . . . . . . . . . . . . . . . . . . . 19
No. of capacitive sensing channels available on STM32F051xx devices. . . . . . . . . . . . . . 19
Timer feature comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Comparison of I2C analog and digital filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
STM32F051xx I2C implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
STM32F051xx USART implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
STM32F051xx SPI/I2S implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Legend/abbreviations used in the pinout table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Pin definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Alternate functions selected through GPIOA_AFR registers for port A . . . . . . . . . . . . . . . 37
Alternate functions selected through GPIOB_AFR registers for port B . . . . . . . . . . . . . . . 38
STM32F051xx peripheral register boundary addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Operating conditions at power-up / power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Embedded reset and power control block characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 47
Programmable voltage detector characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Embedded internal reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Typical and maximum current consumption from the VDD supply at VDD = 3.6 . . . . . . . . . 50
Typical and maximum current consumption from the VDDA supply . . . . . . . . . . . . . . . . . . 51
Typical and maximum current consumption in Stop and Standby modes . . . . . . . . . . . . . 52
Typical and maximum current consumption from the VBAT supply. . . . . . . . . . . . . . . . . . . 53
Typical current consumption in Run mode, code with data processing
running from Flash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Typical current consumption in Sleep mode, code running from Flash or RAM . . . . . . . . . 55
Switching output I/O current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Peripheral current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Low-power mode wakeup timings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
High-speed external user clock characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Low-speed external user clock characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
HSE oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
LSE oscillator characteristics (fLSE = 32.768 kHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
HSI oscillator characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
HSI14 oscillator characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
LSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Flash memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Flash memory endurance and data retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
EMS characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
EMI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
ESD absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
DocID022265 Rev 4
5/115
6
List of tables
Table 48.
Table 49.
Table 50.
Table 51.
Table 52.
Table 53.
Table 54.
Table 55.
Table 56.
Table 57.
Table 58.
Table 59.
Table 60.
Table 61.
Table 62.
Table 63.
Table 64.
Table 65.
Table 66.
Table 67.
Table 68.
Table 69.
Table 70.
Table 71.
Table 72.
Table 73.
Table 74.
Table 75.
6/115
STM32F051xx
I/O current injection susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
I/O static characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Output voltage characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
I/O AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
RAIN max for fADC = 14 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
ADC accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
DAC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Comparator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
TS characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
VBAT monitoring characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
TIMx characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
IWDG min/max timeout period at 40 kHz (LSI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
WWDG min/max timeout value at 48 MHz (PCLK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
I2C characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
I2C analog filter characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
SPI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
I2S characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
LQFP64 – 10 x 10 mm 64 pin low-profile quad flat package mechanical data . . . . . . . . . . 96
LQFP48 – 7 x 7 mm, 48-pin low-profile quad flat package mechanical data . . . . . . . . . . . 98
LQFP32 – 7 x 7mm 32-pin low-profile quad flat package mechanical data . . . . . . . . . . . 100
UFBGA64 – 5 x 5 mm, 0.5 mm pitch, package mechanical data . . . . . . . . . . . . . . . . . . . 103
UFQFPN48 – 7 x 7 mm, 0.5 mm pitch, package mechanical data . . . . . . . . . . . . . . . . . . 105
UFQFPN32 – 32-lead ultra thin fine pitch quad flat no-lead package (5 x 5),
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Package thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Document revision history. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
DocID022265 Rev 4
STM32F051xx
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.
Figure 43.
Figure 44.
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Clock tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
LQFP64 64-pin package pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
UFBGA64 64-pin package ball-out (top view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
LQFP48 48-pin package pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
UFQFPN48 48-pin package pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
LQFP32 32-pin package pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
UFQFPN32 32-pin package pinout (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
STM32F051xx memory map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Pin loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Current consumption measurement scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
High-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Low-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Typical application with an 8 MHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Typical application with a 32.768 kHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
HSI oscillator accuracy characterization results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
HSI14 oscillator accuracy characterization results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
TC and TTa I/O input characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Five volt tolerant (FT and FTf) I/O input characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
I/O AC characteristics definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Recommended NRST pin protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
ADC accuracy characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Typical connection diagram using the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
12-bit buffered / non-buffered DAC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
I2C bus AC waveforms and measurement circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
SPI timing diagram - slave mode and CPHA = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
SPI timing diagram - slave mode and CPHA = 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
SPI timing diagram - master mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
I2S slave timing diagram (Philips protocol). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
I2S master timing diagram (Philips protocol) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
LQFP64 – 10 x 10 mm 64 pin low-profile quad flat package outline. . . . . . . . . . . . . . . . . . 96
LQFP64 recommended footprint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
LQFP48 – 7 x 7 mm, 48 pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . 98
LQFP48 recommended footprint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
LQFP32 – 7 x 7mm 32-pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . 100
LQFP32 recommended footprint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
UFBGA64 - 5 x 5 mm, 0.5 mm pitch, package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
UFQFPN48 – 7 x 7 mm, 0.5 mm pitch, package outline. . . . . . . . . . . . . . . . . . . . . . . . . . 104
UFQFPN48 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
UFQFPN32 – 32-lead ultra thin fine pitch quad flat no-lead package outline (5 x 5) . . . . 106
UFQFPN32 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
LQFP64 PD max vs. TA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
DocID022265 Rev 4
7/115
7
Introduction
1
STM32F051xx
Introduction
This datasheet provides the ordering information and mechanical device characteristics of
the STM32F051xx microcontrollers.
This document should be read in conjunction with the STM32F0xxxx reference manual
(RM0091). The reference manual is available from the STMicroelectronics website
www.st.com.
For information on the ARM Cortex™-M0 core, please refer to the Cortex™-M0 Technical
Reference Manual, available from the www.arm.com website at the following address:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0432c/index.html.
8/115
DocID022265 Rev 4
STM32F051xx
2
Description
Description
The STM32F051xx microcontrollers incorporate the high-performance ARM Cortex™-M0
32-bit RISC core operating at a 48 MHz frequency, high-speed embedded memories (up to
64 Kbytes of Flash memory and 8 Kbytes of SRAM), and an extensive range of enhanced
peripherals and I/Os. All devices offer standard communication interfaces (up to two I2Cs,
two SPIs, one I2S, one HDMI CEC and up to two USARTs), one 12-bit ADC, one 12-bit
DAC, up to six general-purpose 16-bit timers, a 32-bit timer and an advanced-control PWM
timer.
The STM32F051xx microcontrollers operate in the -40 to +85 °C and -40 to +105 °C
temperature ranges from a 2.0 to 3.6 V power supply. A comprehensive set of power-saving
modes allows the design of low-power applications.
The STM32F051xx microcontrollers include devices in six different packages ranging from
32 pins to 64 pins. Depending on the device chosen, different sets of peripherals are
included. The description below provides an overview of the complete range of
STM32F051xx peripherals proposed.
These features make the STM32F051xx microcontrollers suitable for a wide range of
applications such as application control and user interfaces, handheld equipment, A/V
receivers and digital TV, PC peripherals, gaming and GPS platforms, industrial applications,
PLCs, inverters, printers, scanners, alarm systems, video intercoms, and HVACs.
DocID022265 Rev 4
9/115
26
Description
STM32F051xx
Table 2. STM32F051xx family device features and peripheral counts
Peripheral
Flash (Kbytes)
STM32F051Kx
16
32
STM32F051Cx
64
16
32
SRAM (Kbytes)
Timers
64
Advanced
control
1 (16-bit)
General
purpose
5 (16-bit)
1 (32-bit)
Basic
1 (16-bit)
1 [1](2)
2
I C
USART
1
(4)
1
1 [1](2)
32
(3)
1
(3)
2
1(4)
2
2
2 [1]
(3)
1
2
1(4)
2
1
1
(10 ext. + 3 int.)
1
(16 ext. + 3 int.)
GPIOs
25 (on LQFP32)
27 (on UFQFPN32)
39
55
Capacitive sensing
channels
13 (on LQFP32)
14 (on UFQFPN32)
17
18
1
16 ext. + 3 int.
12-bit ADC
(number of channels)
Analog comparator
2
Max. CPU frequency
48 MHz
Operating voltage
Operating temperature
Packages
2.0 to 3.6 V
Ambient operating temperature: -40 °C to 85 °C / -40 °C to 105 °C
Junction temperature: -40 °C to 125 °C
LQFP32
UFQFPN32
LQFP48
UFQFPN48
1. The SPI1 interface can be used either in SPI mode or in I2S audio mode.
2. SPI2 is not present.
3. I2C2 is not present.
4. USART2 is not present.
10/115
64
1 [1](2)
2 [1]
CEC
12-bit ADC
(number of channels)
16
8
SPI [I2S](1)
Comm.
interfaces
STM32F051Rx
DocID022265 Rev 4
LQFP64
UFBGA64
STM32F051xx
Description
Figure 1. Block diagram
%XVPDWUL[
&257(;0&38
I+&/. 0+]
19,&
2EO
)ODVK
LQWHUIDFH
9''
6HULDO
:LUH
'HEXJ
)ODVK
.%
ELWV
65$0
FRQWUROOHU
6:&/.
6:',2
DV$)
65$0
.%
32:(5
92/75(*
9729
325
5HVHW
,QW
6833/<
683(59,6,21
3253'5
#9''$
5&+60+]
5&+60+]
*3'0$
FKDQQHOV
#9''$
#9''
;7$/26&
0+]
3//
*3,2SRUW$
3%>@
*3,2SRUW%
3&>@
*3,2SRUW&
3'
*3,2SRUW'
3)>@
3)>@
*3,2SRUW)
JURXSVRI
FKDQQHOV
$QDORJ
VZLWFKHV
7RXFK
6HQVLQJ
&RQWUROOHU
6<1&
,:'*
3RZHU
&RQWUROOHU
&5&
;7$/N+]
%DFNXS
UHJ
026,6'
0,620&.
6&.&.
166:6DV$)
$+%
026,0,62
6&.166
DV$)
(;7,7
:.83
::'*
63,,6
9%$7 WR9
26&B,13&
26&B2873&
7$03(557&
$/$50287
57&LQWHUIDFH
7,0(5
FKDQQHOV
FRPSOFKDQQHOV
%5.(75LQSXWDV$)
7,0(5
FK(75DV$)
7,0(5
FK(75DV$)
7,0(5
FKDQQHODV$)
7,0(5
FKDQQHOV
FRPSO%5.DV$)
7,0(5
FKDQQHO
FRPSO%5.DV$)
7,0(5
FKDQQHO
FRPSO%5.DV$)
$3%
$)
26&B,13)
26&B2873)
#96:
57&
$+%GHFRGHU
3$>@
$+%3&/.
$3%3&/.
$'&&/.
&(&&/.
86$57&/.
+&/.
)&/.
1567
9''$
9''
39'
5&/6
5(6(7
&/2&.
&21752/
9'' WR9
966
#9''
,5B287DV$)
'%*0&8
86$57
63,
86$57
5;7;&76576
&.DV$)
5;7;&76576
&.DV$)
6<6&)*,)
,1387
,1387
287387
DV$)
$'LQSXWV
*3FRPSDUDWRU
*3FRPSDUDWRU
#9''$
7HPS
VHQVRU
ELW
$'&
9''$
966$
,&
6&/6'$60%$
P$IRU)0DV$)
,&
6&/6'$
DV$)
+'0,&(&
&(&
DV$)
,)
7,0(5
#9''$
,)
ELW
'$&
'$&B287DV$)
#9''$
06Y9
DocID022265 Rev 4
11/115
26
Functional overview
STM32F051xx
3
Functional overview
3.1
ARM® CortexTM-M0 core with embedded Flash and SRAM
The ARM Cortex™-M0 processor is the latest generation of ARM processors for embedded
systems. It has been developed to provide a low-cost platform that meets the needs of MCU
implementation, with a reduced pin count and low-power consumption, while delivering
outstanding computational performance and an advanced system response to interrupts.
The ARM Cortex™-M0 32-bit RISC processor features exceptional code-efficiency,
delivering the high-performance expected from an ARM core in the memory size usually
associated with 8- and 16-bit devices.
The STM32F0xx family has an embedded ARM core and is therefore compatible with all
ARM tools and software.
Figure 1 shows the general block diagram of the device family.
3.2
Memories
The device has the following features:

8 Kbytes of embedded SRAM accessed (read/write) at CPU clock speed with 0 wait
states and featuring embedded parity checking with exception generation for fail-critical
applications.

The non-volatile memory is divided into two arrays:
–
16 to 64 Kbytes of embedded Flash memory for programs and data
–
Option bytes
The option bytes are used to write-protect the memory (with 4 KB granularity) and/or
readout-protect the whole memory with the following options:
–
Level 0: no readout protection
–
Level 1: memory readout protection, the Flash memory cannot be read from or
written to if either debug features are connected or boot in RAM is selected
–
Level 2: chip readout protection, debug features (Cortex-M0 serial wire) and boot
in RAM selection disabled
3.3
Boot modes
At startup, the boot pin and boot selector option bit are used to select one of three boot
options:

Boot from User Flash

Boot from System Memory

Boot from embedded SRAM
The boot loader is located in System Memory. It is used to reprogram the Flash memory by
using USART on pins PA14/PA15 or PA9/PA10.
12/115
DocID022265 Rev 4
STM32F051xx
3.4
Functional overview
Cyclic redundancy check calculation unit (CRC)
The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit
data word and a CRC-32 (Ethernet) polynomial.
Among other applications, CRC-based techniques are used to verify data transmission or
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of
verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of
the software during runtime, to be compared with a reference signature generated at linktime and stored at a given memory location.
3.5
Power management
3.5.1
Power supply schemes



VDD = 2.0 to 3.6 V: external power supply for I/Os and the internal regulator. Provided
externally through VDD pins.
VDDA = 2.0 to 3.6 V: external analog power supply for ADC, Reset blocks, RCs and
PLL (minimum voltage to be applied to VDDA is 2.4 V when the ADC and DAC are
used). The VDDA voltage level must be always greater or equal to the VDD voltage level
and must be provided first.
VBAT = 1.65 to 3.6 V: power supply for RTC, external clock 32 kHz oscillator and
backup registers (through power switch) when VDD is not present.
For more details on how to connect power pins, refer to Figure 12: Power supply scheme.
3.5.2
Power supply supervisors
The device has integrated power-on reset (POR) and power-down reset (PDR) circuits.
They are always active, and ensure proper operation above a threshold of 2 V. The device
remains in reset mode when the monitored supply voltage is below a specified threshold,
VPOR/PDR, without the need for an external reset circuit.

The POR monitors only the VDD supply voltage. During the startup phase it is required
that VDDA should arrive first and be greater than or equal to VDD.

The PDR monitors both the VDD and VDDA supply voltages, however the VDDA power
supply supervisor can be disabled (by programming a dedicated Option bit) to reduce
the power consumption if the application design ensures that VDDA is higher than or
equal to VDD.
The device features an embedded programmable voltage detector (PVD) that monitors the
VDD power supply and compares it to the VPVD threshold. An interrupt can be generated
when VDD drops below the VPVD threshold and/or when VDD is higher than the VPVD
threshold. The interrupt service routine can then generate a warning message and/or put
the MCU into a safe state. The PVD is enabled by software.
3.5.3
Voltage regulator
The regulator has two operating modes and it is always enabled after reset.

Main (MR) is used in normal operating mode (Run).

Low power (LPR) can be used in Stop mode where the power demand is reduced.
DocID022265 Rev 4
13/115
26
Functional overview
STM32F051xx
In Standby mode, it is put in power down mode. In this mode, the regulator output is in high
impedance and the kernel circuitry is powered down, inducing zero consumption (but the
contents of the registers and SRAM are lost).
3.5.4
Low-power modes
The STM32F051xx microcontrollers support three low-power modes to achieve the best
compromise between low power consumption, short startup time and available wakeup
sources:

Sleep mode
In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can
wake up the CPU when an interrupt/event occurs.

Stop mode
Stop mode achieves very low power consumption while retaining the content of SRAM
and registers. All clocks in the 1.8 V domain are stopped, the PLL, the HSI RC and the
HSE crystal oscillators are disabled. The voltage regulator can also be put either in
normal or in low power mode.
The device can be woken up from Stop mode by any of the EXTI lines. The EXTI line
source can be one of the 16 external lines, the PVD output, RTC alarm, COMPx, I2C1,
USART1 or the CEC.
The I2C1, USART1 and the CEC can be configured to enable the HSI RC oscillator for
processing incoming data. If this is used when the voltage regulator is put in low power
mode, the regulator is first switched to normal mode before the clock is provided to the
given peripheral.

Standby mode
The Standby mode is used to achieve the lowest power consumption. The internal
voltage regulator is switched off so that the entire 1.8 V domain is powered off. The
PLL, the HSI RC and the HSE crystal oscillators are also switched off. After entering
Standby mode, SRAM and register contents are lost except for registers in the RTC
domain and Standby circuitry.
The device exits Standby mode when an external reset (NRST pin), an IWDG reset, a
rising edge on the WKUP pins, or an RTC event occurs.
Note:
14/115
The RTC, the IWDG, and the corresponding clock sources are not stopped by entering
Stop or Standby mode.
DocID022265 Rev 4
STM32F051xx
3.6
Functional overview
Clocks and startup
System clock selection is performed on startup, however the internal RC 8 MHz oscillator is
selected as default CPU clock on reset. An external 4-32 MHz clock can be selected, in
which case it is monitored for failure. If failure is detected, the system automatically switches
back to the internal RC oscillator. A software interrupt is generated if enabled. Similarly, full
interrupt management of the PLL clock entry is available when necessary (for example on
failure of an indirectly used external crystal, resonator or oscillator).
Several prescalers allow the application to configure the frequency of the AHB and the APB
domains. The maximum frequency of the AHB and the APB domains is 48 MHz.
Figure 2. Clock tree
&,)4&#,+
TO&LASHPROGRAMMINGINTERFACE
(3)
TO)#
393#,+
TO)3
,3%
-(Z (3)
(3)2#
TO#%#
(#,+
0,,32#
0,,-5,
0,,
XX
X
37
(3)
0,,#,+
(3%
!("
!("
PRESCALER
393#,+
#33
/3#?/54
/3#?). -(Z
(3%/3#
-(Z (3)
(3)2#
/3#?).
/3#?/54
,3%/3#
K(Z
,3%
24##,+
TO24#
!0"
PRESCALER
TO!("BUSCORE
MEMORYAND$-!
TOCORTEX3YSTEMTIMER
&(#,+#ORTEXFREERUNNINGCLOCK
0#,+
)F!0"PRESCALER
XELSEX
!$#
0RESCALER
0#,+
393#,+
(3)
,3%
TO!0"PERIPHERALS
TO4)-
TO!$#
-(ZMAX
TO53!24
24#3%,;=
,3)2#
K(Z
,3)
TO)7$'
0,,#,+
-#/
-AINCLOCK
OUTPUT
(3)
(3)
(3%
393#,+
,3)
,3%
-#/
-36
DocID022265 Rev 4
15/115
26
Functional overview
3.7
STM32F051xx
General-purpose inputs/outputs (GPIOs)
Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as
input (with or without pull-up or pull-down) or as peripheral alternate function. Most of the
GPIO pins are shared with digital or analog alternate functions.
The I/O configuration can be locked if needed following a specific sequence in order to
avoid spurious writing to the I/Os registers.
3.8
Direct memory access controller (DMA)
The 5-channel general-purpose DMAs manage memory-to-memory, peripheral-to-memory
and memory-to-peripheral transfers.
The DMA supports circular buffer management, removing the need for user code
intervention when the controller reaches the end of the buffer.
Each channel is connected to dedicated hardware DMA requests, with support for software
trigger on each channel. Configuration is made by software and transfer sizes between
source and destination are independent.
DMA can be used with the main peripherals: SPI, I2S, I2C, USART, all TIMx timers (except
TIM14), DAC and ADC.
3.9
Interrupts and events
3.9.1
Nested vectored interrupt controller (NVIC)
The STM32F0xx family embeds a nested vectored interrupt controller able to handle up to
32 maskable interrupt channels (not including the 16 interrupt lines of Cortex™-M0) and 4
priority levels.

Closely coupled NVIC gives low latency interrupt processing

Interrupt entry vector table address passed directly to the core

Closely coupled NVIC core interface

Allows early processing of interrupts

Processing of late arriving higher priority interrupts

Support for tail-chaining

Processor state automatically saved

Interrupt entry restored on interrupt exit with no instruction overhead
This hardware block provides flexible interrupt management features with minimal interrupt
latency.
3.9.2
Extended interrupt/event controller (EXTI)
The extended interrupt/event controller consists of 24 edge detector lines used to generate
interrupt/event requests and wake-up the system. Each line can be independently
configured to select the trigger event (rising edge, falling edge, both) and can be masked
independently. A pending register maintains the status of the interrupt requests. The EXTI
can detect an external line with a pulse width shorter than the internal clock period. Up to 55
GPIOs can be connected to the 16 external interrupt lines.
16/115
DocID022265 Rev 4
STM32F051xx
3.10
Functional overview
Analog to digital converter (ADC)
The 12-bit analog to digital converter has up to 16 external and 3 internal (temperature
sensor, voltage reference, VBAT voltage measurement) channels and performs conversions
in single-shot or scan modes. In scan mode, automatic conversion is performed on a
selected group of analog inputs.
The ADC can be served by the DMA controller.
An analog watchdog feature allows very precise monitoring of the converted voltage of one,
some or all selected channels. An interrupt is generated when the converted voltage is
outside the programmed thresholds.
3.10.1
Temperature sensor
The temperature sensor (TS) generates a voltage VSENSE that varies linearly with
temperature.
The temperature sensor is internally connected to the ADC_IN16 input channel which is
used to convert the sensor output voltage into a digital value.
The sensor provides good linearity but it has to be calibrated to obtain good overall
accuracy of the temperature measurement. As the offset of the temperature sensor varies
from chip to chip due to process variation, the uncalibrated internal temperature sensor is
suitable for applications that detect temperature changes only.
To improve the accuracy of the temperature sensor measurement, each device is
individually factory-calibrated by ST. The temperature sensor factory calibration data are
stored by ST in the system memory area, accessible in read-only mode.
Table 3. Temperature sensor calibration values
Calibration value name
3.10.2
Description
Memory address
TS_CAL1
TS ADC raw data acquired at a
temperature of 30 °C (5 °C),
VDDA= 3.3 V (10 mV)
0x1FFF F7B8 - 0x1FFF F7B9
TS_CAL2
TS ADC raw data acquired at a
temperature of 110 °C (5 °C),
VDDA= 3.3 V (10 mV)
0x1FFF F7C2 - 0x1FFF F7C3
Internal voltage reference (VREFINT)
The internal voltage reference (VREFINT) provides a stable (bandgap) voltage output for the
ADC and Comparators. VREFINT is internally connected to the ADC_IN17 input channel. The
precise voltage of VREFINT is individually measured for each part by ST during production
test and stored in the system memory area. It is accessible in read-only mode.
Table 4. Internal voltage reference calibration values
Calibration value name
VREFINT_CAL
Description
Memory address
Raw data acquired at a
temperature of 30 °C (5 °C), 0x1FFF F7BA - 0x1FFF F7BB
VDDA= 3.3 V (10 mV)
DocID022265 Rev 4
17/115
26
Functional overview
3.10.3
STM32F051xx
VBAT battery voltage monitoring
This embedded hardware feature allows the application to measure the VBAT battery voltage
using the internal ADC channel ADC_IN18. As the VBAT voltage may be higher than VDDA,
and thus outside the ADC input range, the VBAT pin is internally connected to a bridge
divider by 2. As a consequence, the converted digital value is half the VBAT voltage.
3.11
Digital-to-analog converter (DAC)
The 12-bit buffered DAC channel can be used to convert digital signals into analog voltage
signal outputs. The chosen design structure is composed of integrated resistor strings and
an amplifier in non-inverting configuration.
This digital Interface supports the following features:

Left or right data alignment in 12-bit mode

Synchronized update capability

DMA capability

External triggers for conversion
Five DAC trigger inputs are used in the device. The DAC is triggered through the timer
trigger outputs and the DAC interface is generating its own DMA requests.
3.12
Comparators (COMP)
The device embeds two fast rail-to-rail low-power comparators with programmable
reference voltage (internal or external), hysteresis and speed (low speed for low power) and
with selectable output polarity.
The reference voltage can be one of the following:

External I/O

DAC output pins

Internal reference voltage or submultiple (1/4, 1/2, 3/4). Refer to Table 24: Embedded
internal reference voltage for the value and precision of the internal reference voltage.
Both comparators can wake up from STOP mode, generate interrupts and breaks for the
timers and can be also combined into a window comparator.
3.13
Touch sensing controller (TSC)
The STM32F051xx devices provide a simple solution for adding capacitive sensing
functionality to any application. These devices offer up to 18 capacitive sensing channels
distributed over 6 analog I/O groups.
Capacitive sensing technology is able to detect the presence of a finger near a sensor which
is protected from direct touch by a dielectric (glass, plastic...). The capacitive variation
introduced by the finger (or any conductive object) is measured using a proven
implementation based on a surface charge transfer acquisition principle. It consists of
charging the sensor capacitance and then transferring a part of the accumulated charges
into a sampling capacitor until the voltage across this capacitor has reached a specific
18/115
DocID022265 Rev 4
STM32F051xx
Functional overview
threshold. To limit the CPU bandwidth usage, this acquisition is directly managed by the
hardware touch sensing controller and only requires few external components to operate.
The touch sensing controller is fully supported by the STMTouch touch sensing firmware
library, which is free to use and allows touch sensing functionality to be implemented reliably
in the end application.
Table 5. Capacitive sensing GPIOs available on STM32F051xx devices
Group
1
2
3
Capacitive sensing
signal name
Pin
name
Capacitive sensing
signal name
Pin
name
TSC_G1_IO1
PA0
TSC_G4_IO1
PA9
TSC_G1_IO2
PA1
TSC_G4_IO2
PA10
TSC_G1_IO3
PA2
TSC_G4_IO3
PA11
TSC_G1_IO4
PA3
TSC_G4_IO4
PA12
TSC_G2_IO1
PA4
TSC_G5_IO1
PB3
TSC_G2_IO2
PA5
TSC_G5_IO2
PB4
TSC_G2_IO3
PA6
TSC_G5_IO3
PB6
TSC_G2_IO4
PA7
TSC_G5_IO4
PB7
TSC_G3_IO1
PC5
TSC_G6_IO1
PB11
TSC_G3_IO2
PB0
TSC_G6_IO2
PB12
TSC_G3_IO3
PB1
TSC_G6_IO3
PB13
TSC_G3_IO4
PB2
TSC_G6_IO4
PB14
Group
4
5
6
Table 6. No. of capacitive sensing channels available on STM32F051xx devices
Number of capacitive sensing channels
Analog I/O group
STM32F051Rx
STM32F051Cx
STM32F051Kx
(UFQFPN32)
STM32F051Kx
(LQFP32)
G1
3
3
3
3
G2
3
3
3
3
G3
3
2
2
1
G4
3
3
3
3
G5
3
3
3
3
G6
3
3
0
0
Number of capacitive
sensing channels
18
17
14
13
DocID022265 Rev 4
19/115
26
Functional overview
3.14
STM32F051xx
Timers and watchdogs
The STM32F051xx devices include up to six general-purpose timers, one basic timer and
an advanced control timer.
Table 7 compares the features of the advanced-control, general-purpose and basic timers.
Table 7. Timer feature comparison
Timer
type
Timer
Counter
resolution
Counter
type
Prescaler
factor
DMA request
generation
Advanced
control
TIM1
16-bit
Up,
down,
up/down
Any integer
between 1
and 65536
Yes
4
Yes
TIM2
32-bit
Up,
down,
up/down
Any integer
between 1
and 65536
Yes
4
No
TIM3
16-bit
Up,
down,
up/down
Any integer
between 1
and 65536
Yes
4
No
TIM14
16-bit
Up
Any integer
between 1
and 65536
No
1
No
TIM15
16-bit
Up
Any integer
between 1
and 65536
Yes
2
Yes
TIM16,
TIM17
16-bit
Up
Any integer
between 1
and 65536
Yes
1
Yes
TIM6
16-bit
Up
Any integer
between 1
and 65536
Yes
0
No
General
purpose
Basic
20/115
DocID022265 Rev 4
Capture/compare Complementary
channels
outputs
STM32F051xx
3.14.1
Functional overview
Advanced-control timer (TIM1)
The advanced-control timer (TIM1) can be seen as a three-phase PWM multiplexed on six
channels. It has complementary PWM outputs with programmable inserted dead times. It
can also be seen as a complete general-purpose timer. The four independent channels can
be used for:

Input capture

Output compare

PWM generation (edge or center-aligned modes)

One-pulse mode output
If configured as a standard 16-bit timer, it has the same features as the TIMx timer. If
configured as the 16-bit PWM generator, it has full modulation capability (0-100%).
The counter can be frozen in debug mode.
Many features are shared with those of the standard timers which have the same
architecture. The advanced control timer can therefore work together with the other timers
via the Timer Link feature for synchronization or event chaining.
3.14.2
General-purpose timers (TIM2..3, TIM14..17)
There are six synchronizable general-purpose timers embedded in the STM32F051xx
devices (see Table 7 for differences). Each general-purpose timer can be used to generate
PWM outputs, or as simple time base.
TIM2, TIM3
STM32F051xx devices feature two synchronizable 4-channel general-purpose timers. TIM2
is based on a 32-bit auto-reload up/downcounter and a 16-bit prescaler. TIM3 is based on a
16-bit auto-reload up/downcounter and a 16-bit prescaler. They feature 4 independent
channels each for input capture/output compare, PWM or one-pulse mode output. This
gives up to 12 input captures/output compares/PWMs on the largest packages.
The TIM2 and TIM3 general-purpose timers can work together or with the TIM1 advancedcontrol timer via the Timer Link feature for synchronization or event chaining.
TIM2 and TIM3 both have independent DMA request generation.
These timers are capable of handling quadrature (incremental) encoder signals and the
digital outputs from 1 to 3 hall-effect sensors.
Their counters can be frozen in debug mode.
TIM14
This timer is based on a 16-bit auto-reload upcounter and a 16-bit prescaler.
TIM14 features one single channel for input capture/output compare, PWM or one-pulse
mode output.
Its counter can be frozen in debug mode.
TIM15, TIM16 and TIM17
These timers are based on a 16-bit auto-reload upcounter and a 16-bit prescaler.
TIM15 has two independent channels, whereas TIM16 and TIM17 feature one single
DocID022265 Rev 4
21/115
26
Functional overview
STM32F051xx
channel for input capture/output compare, PWM or one-pulse mode output.
The TIM15, TIM16 and TIM17 timers can work together, and TIM15 can also operate
withTIM1 via the Timer Link feature for synchronization or event chaining.
TIM15 can be synchronized with TIM16 and TIM17.
TIM15, TIM16 and TIM17 have a complementary output with dead-time generation and
independent DMA request generation.
Their counters can be frozen in debug mode.
3.14.3
Basic timer TIM6
This timer is mainly used for DAC trigger generation. It can also be used as a generic 16-bit
time base.
3.14.4
Independent watchdog (IWDG)
The independent watchdog is based on an 8-bit prescaler and 12-bit downcounter with
user-defined refresh window. It is clocked from an independent 40 kHz internal RC and as it
operates independently from the main clock, it can operate in Stop and Standby modes. It
can be used either as a watchdog to reset the device when a problem occurs, or as a free
running timer for application timeout management. It is hardware or software configurable
through the option bytes. The counter can be frozen in debug mode.
3.14.5
System window watchdog (WWDG)
The system window watchdog is based on a 7-bit downcounter that can be set as free
running. It can be used as a watchdog to reset the device when a problem occurs. It is
clocked from the APB clock (PCLK). It has an early warning interrupt capability and the
counter can be frozen in debug mode.
3.14.6
SysTick timer
This timer is dedicated to real-time operating systems, but could also be used as a standard
down counter. It features:

A 24-bit down counter

Autoreload capability

Maskable system interrupt generation when the counter reaches 0

Programmable clock source (HCLK or HCLK/8)
3.15
Real-time clock (RTC) and backup registers
The RTC and the 5 backup registers are supplied through a switch that takes power either
on VDD supply when present or through the VBAT pin. The backup registers are five 32-bit
registers used to store 20 bytes of user application data when VDD power is not present.
They are not reset by a system or power reset, or when the device wakes up from Standby
mode.
22/115
DocID022265 Rev 4
STM32F051xx
Functional overview
The RTC is an independent BCD timer/counter. Its main features are the following:

Calendar with subseconds, seconds, minutes, hours (12 or 24 format), week day, date,
month, year, in BCD (binary-coded decimal) format.

Automatically correction for 28, 29 (leap year), 30, and 31 day of the month.

Programmable alarm with wake up from Stop and Standby mode capability.

On-the-fly correction from 1 to 32767 RTC clock pulses. This can be used to
synchronize it with a master clock.

Digital calibration circuit with 1 ppm resolution, to compensate for quartz crystal
inaccuracy.

2 anti-tamper detection pins with programmable filter. The MCU can be woken up from
Stop and Standby modes on tamper event detection.

Timestamp feature which can be used to save the calendar content. This function can
triggered by an event on the timestamp pin, or by a tamper event. The MCU can be
woken up from Stop and Standby modes on timestamp event detection.

Reference clock detection: a more precise second source clock (50 or 60 Hz) can be
used to enhance the calendar precision.
The RTC clock sources can be:

A 32.768 kHz external crystal

A resonator or oscillator

The internal low-power RC oscillator (typical frequency of 40 kHz)

The high-speed external clock divided by 32
3.16
Inter-integrated circuit interfaces (I2C)
Up to two I2C interfaces (I2C1 and I2C2) can operate in multimaster or slave modes. Both
can support Standard mode (up to 100 kbit/s) or Fast mode (up to 400 kbit/s) and I2C1
supports also Fast Mode Plus (up to 1 Mbit/s) with 20 mA output drive.
Both support 7-bit and 10-bit addressing modes, multiple 7-bit slave addresses (2
addresses, 1 with configurable mask). They also include programmable analog and digital
noise filters.
Table 8. Comparison of I2C analog and digital filters
Analog filter
Digital filter
Pulse width of
suppressed spikes
 50 ns
Programmable length from 1 to 15
I2C peripheral clocks
Benefits
Available in Stop mode
1. Extra filtering capability vs.
standard requirements.
2. Stable length
Drawbacks
Variations depending on
temperature, voltage, process
Wakeup from Stop on address
match is not available when digital
filter is enabled.
In addition, I2C1 provides hardware support for SMBUS 2.0 and PMBUS 1.1: ARP
capability, Host notify protocol, hardware CRC (PEC) generation/verification, timeouts
verifications and ALERT protocol management. I2C1 also has a clock domain independent
DocID022265 Rev 4
23/115
26
Functional overview
STM32F051xx
from the CPU clock, allowing the I2C1 to wake up the MCU from Stop mode on address
match.
The I2C interfaces can be served by the DMA controller.
Refer to Table 9 for the differences between I2C1 and I2C2.
Table 9. STM32F051xx I2C implementation
I2C features(1)
I2C1
I2C2
7-bit addressing mode
X
X
10-bit addressing mode
X
X
Standard mode (up to 100 kbit/s)
X
X
Fast mode (up to 400 kbit/s)
X
X
Fast Mode Plus with 20mA output drive I/Os (up to 1 Mbit/s)
X
Independent clock
X
SMBus
X
Wakeup from STOP
X
1. X = supported.
3.17
Universal synchronous/asynchronous receiver transmitters
(USART)
The device embeds up to two universal synchronous/asynchronous receiver transmitters
(USART1 and USART2), which communicate at speeds of up to 6 Mbit/s.
They provide hardware management of the CTS, RTS and RS485 DE signals,
multiprocessor communication mode, master synchronous communication and single-wire
half-duplex communication mode. USART1 supports also SmartCard communication (ISO
7816), IrDA SIR ENDEC, LIN Master/Slave capability and auto baud rate feature, and has a
clock domain independent from the CPU clock, allowing USART1 to wake up the MCU from
Stop mode.
The USART interfaces can be served by the DMA controller.
Refer to Table 10 for the differences between USART1 and USART2.
Table 10. STM32F051xx USART implementation
USART modes/features(1)
24/115
USART1
USART2
Hardware flow control for modem
X
X
Continuous communication using DMA
X
X
Multiprocessor communication
X
X
Synchronous mode
X
X
Smartcard mode
X
Single-wire half-duplex communication
X
DocID022265 Rev 4
X
STM32F051xx
Functional overview
Table 10. STM32F051xx USART implementation (continued)
USART modes/features(1)
USART1
IrDA SIR ENDEC block
X
LIN mode
X
Dual clock domain and wakeup from Stop mode
X
Receiver timeout interrupt
X
Modbus communication
X
Auto baud rate detection
X
Driver Enable
X
USART2
X
1. X = supported.
3.18
Serial peripheral interface (SPI)/Inter-integrated sound
interfaces (I2S)
Up to two SPIs are able to communicate up to 18 Mbits/s in slave and master modes in fullduplex and half-duplex communication modes. The 3-bit prescaler gives 8 master mode
frequencies and the frame size is configurable from 4 bits to 16 bits.
One standard I2S interface (multiplexed with SPI1) supporting four different audio standards
can operate as master or slave at half-duplex communication mode. It can be configured to
transfer 16 and 24 or 32 bits with 16-bit or 32-bit data resolution and synchronized by a
specific signal. Audio sampling frequency from 8 kHz up to 192 kHz can be set by an 8-bit
programmable linear prescaler. When operating in master mode, it can output a clock for an
external audio component at 256 times the sampling frequency.
Refer to Table 11 for the differences between SPI1 and SPI2.
Table 11. STM32F051xx SPI/I2S implementation
SPI features(1)
SPI1
SPI2
Hardware CRC calculation
X
X
Rx/Tx FIFO
X
X
NSS pulse mode
X
X
I2S mode
X
TI mode
X
X
1. X = supported.
DocID022265 Rev 4
25/115
26
Functional overview
3.19
STM32F051xx
High-definition multimedia interface (HDMI) - consumer
electronics control (CEC)
The device embeds a HDMI-CEC controller that provides hardware support for the
Consumer Electronics Control (CEC) protocol (Supplement 1 to the HDMI standard).
This protocol provides high-level control functions between all audiovisual products in an
environment. It is specified to operate at low speeds with minimum processing and memory
overhead. It has a clock domain independent from the CPU clock, allowing the HDMI_CEC
controller to wakeup the MCU from Stop mode on data reception.
3.20
Serial wire debug port (SW-DP)
An ARM SW-DP interface is provided to allow a serial wire debugging tool to be connected
to the MCU.
26/115
DocID022265 Rev 4
STM32F051xx
Pinouts and pin descriptions
0#
0#/3#?).
0#/3#?/54
0&/3#?).
0&/3#?/54
.234
0#
0#
0#
0#
633!
6$$!
0!
0!
0!
,1&0
0&
0&
0!
0!
0!
0!
0!
0!
0#
0#
0#
0#
0"
0"
0"
0"
0!
0!
0!
0!
0#
0#
0"
0"
0"
0"
0"
633
6$$
6"!4
0"
0"
"//4
0"
0"
0"
0"
0"
0$
0# 0# 0# 0!
0!
6$$
633
Figure 3. LQFP64 64-pin package pinout (top view)
0!
0&
0&
4
Pinouts and pin descriptions
-36
DocID022265 Rev 4
27/115
36
Pinouts and pin descriptions
STM32F051xx
Figure 4. UFBGA64 64-pin package ball-out (top view)
$
3&
26&B,1
3&
3%
3%
3%
3$
3$
3$
%
3&
26&B287
9%$7
3%
%227
3'
3&
3&
3$
&
3)
26&B,1
3)
3%
3%
3&
3$
3$
3$
'
3)
26&B287
3)
3%
966
966
3)
3$
3&
(
1567
3&
3&
9''
9''
3)
3&
3&
)
966$
3&
3$
3$
3%
3&
3%
3%
*
3&
3$
3$
3$
3%
3%
3%
3%
+
9''$
3$
3$
3$
3&
3&
3%
3%
069
28/115
DocID022265 Rev 4
STM32F051xx
Pinouts and pin descriptions
6"!4
0#
0#/3#?).
0#/3#?/54
0&/3#?).
0&/3#?/54
.234
633!
6$$!
0!
0!
0!
0"
0!
0"
0"
0"
0"
0"
"//4
,1&0
0&
0&
0!
0!
0!
0!
0!
0!
0"
0"
0"
0"
6$$
0"
633
0"
0"
0"
0"
0!
0!
0!
0!
0!
0!
0"
6$$
633
Figure 5. LQFP48 48-pin package pinout (top view)
-36
6"!4
0!
0"
0!
0"
0"
0"
0"
0"
"//4
0"
6$$
633
Figure 6. UFQFPN48 48-pin package pinout (top view)
0&
0#
0#/3#?).
0#/3#?/54
0&/3#?).
0&/3#?/54
0!
0!
0!
.234
0!
633!
6$$!
0!
0!
0!
0"
0"
0"
0"
8)4)31
6$$
0"
633
0"
0"
0"
0"
0!
0!
0!
0!
0!
0!
0&
0!
069
DocID022265 Rev 4
29/115
36
Pinouts and pin descriptions
STM32F051xx
0"
0!
0"
0"
0"
0"
633
"//4
Figure 7. LQFP32 32-pin package pinout (top view)
6$$
0&/3#?).
0&/3#?/54
.234
6$$!
0!
0!
0!
,1&0
0!
0!
0!
0!
0!
0!
0!
6$$
0"
633
0"
0!
0!
0!
0!
0!
-36
0"
"//4
0"
0"
0"
0"
0"
0!
Figure 8. UFQFPN32 32-pin package pinout (top view)
633
633!
0!
0!
0!
0!
0!
0!
0!
6$$
0!
0!
0!
0!
0!
0"
0"
0"
6$$
0&/3#?).
0&/3#?/54
.234
6$$!
0!
0!
0!
-36
30/115
DocID022265 Rev 4
STM32F051xx
Pinouts and pin descriptions
Table 12. Legend/abbreviations used in the pinout table
Name
Abbreviation
Unless otherwise specified in brackets below the pin name, the pin function during and
after reset is the same as the actual pin name
Pin name
Pin type
I/O structure
S
Supply pin
I
Input only pin
I/O
Input / output pin
FT
5 V tolerant I/O
FTf
5 V tolerant I/O, FM+ capable
TTa
3.3 V tolerant I/O directly connected to ADC
TC
Standard 3.3 V I/O
B
Dedicated BOOT0 pin
RST
Bidirectional reset pin with embedded weak pull-up resistor
Unless otherwise specified by a note, all I/Os are set as floating inputs during and after
reset.
Notes
Pin
functions
Definition
Alternate
functions
Functions selected through GPIOx_AFR registers
Additional
functions
Functions directly selected/enabled through peripheral registers
Table 13. Pin definitions
Pin functions
LQFP48/UFQFPN48
LQFP32
UFQFPN32
1
B2
1
-
-
VBAT
S
I/O structure
UFBGA64
Pin name
(function after
reset)
Pin type
LQFP64
Pin number
Notes
Alternate functions
Additional functions
Backup power supply
-
RTC_TAMP1,
RTC_TS,
RTC_OUT,
WKUP2
2
A2
2
-
-
PC13
I/O
TC
(1)(2)
3
A1
3
-
-
PC14-OSC32_IN
(PC14)
I/O
TC
(1)(2)
-
OSC32_IN
4
B1
4
-
-
PC15-OSC32_OUT
I/O
(PC15)
TC
(1)(2)
-
OSC32_OUT
5
C1
5
2
2
PF0-OSC_IN
(PF0)
I/O
FT
-
OSC_IN
6
D1
6
3
3
PF1-OSC_OUT
(PF1)
I/O
FT
-
OSC_OUT
DocID022265 Rev 4
31/115
36
Pinouts and pin descriptions
STM32F051xx
Table 13. Pin definitions (continued)
Pin functions
LQFP48/UFQFPN48
LQFP32
UFQFPN32
7
E1
7
4
4
NRST
8
E3
-
-
-
PC0
I/O
TTa
EVENTOUT
ADC_IN10
9
E2
-
-
-
PC1
I/O
TTa
EVENTOUT
ADC_IN11
10
F2
-
-
-
PC2
I/O
TTa
EVENTOUT
ADC_IN12
11
A2
-
-
-
PC3
I/O
TTa
EVENTOUT
ADC_IN13
12
F1
8
-
0
VSSA
S
Analog ground
13
H1
9
5
5
VDDA
S
Analog power supply
14
15
16
G2
H2
F3
10
11
12
6
7
8
6
7
8
PA0
PA1
PA2
I/O structure
UFBGA64
Pin name
(function after
reset)
Pin type
LQFP64
Pin number
Notes
I/O RST
I/O
I/O
I/O
Alternate functions
Additional functions
Device reset input / internal reset output
(active low)
TTa
USART2_CTS,
TIM2_CH1_ETR,
COMP1_OUT,
TSC_G1_IO1
ADC_IN0,
COMP1_INM6,
RTC_TAMP2,
WKUP1
TTa
USART2_RTS,
TIM2_CH2,
TSC_G1_IO2,
EVENTOUT
ADC_IN1,
COMP1_INP
TTa
USART2_TX,
TIM2_CH3,
TIM15_CH1,
COMP2_OUT,
TSC_G1_IO3
ADC_IN2,
COMP2_INM6
ADC_IN3,
COMP2_INP
17
G3
13
9
9
PA3
I/O
TTa
USART2_RX,
TIM2_CH4,
TIM15_CH2,
TSC_G1_IO4
18
C2
-
-
-
PF4
I/O
FT
EVENTOUT
-
19
D2
-
-
-
PF5
I/O
FT
EVENTOUT
-
TTa
SPI1_NSS,
I2S1_WS,
USART2_CK,
TIM14_CH1,
TSC_G2_IO1
ADC_IN4,
COMP1_INM4,
COMP2_INM4,
DAC1_OUT
TTa
SPI1_SCK,
I2S1_CK, CEC,
TIM2_CH1_ETR,
TSC_G2_IO2
ADC_IN5,
COMP1_INM5,
COMP2_INM5
20
21
H3
F4
32/115
14
15
10
11
10
11
PA4
PA5
I/O
I/O
DocID022265 Rev 4
STM32F051xx
Pinouts and pin descriptions
Table 13. Pin definitions (continued)
Pin functions
22
G4
16
12
12
PA6
I/O
I/O structure
Pin name
(function after
reset)
Pin type
UFQFPN32
LQFP32
LQFP48/UFQFPN48
UFBGA64
LQFP64
Pin number
Notes
Alternate functions
Additional functions
TTa
SPI1_MISO,
I2S1_MCK,
TIM3_CH1,
TIM1_BKIN,
TIM16_CH1,
COMP1_OUT,
TSC_G2_IO3,
EVENTOUT
ADC_IN6
ADC_IN7
23
H4
17
13
13
PA7
I/O
TTa
SPI1_MOSI,
I2S1_SD,
TIM3_CH2,
TIM14_CH1,
TIM1_CH1N,
TIM17_CH1,
COMP2_OUT,
TSC_G2_IO4,
EVENTOUT
24
H5
-
-
-
PC4
I/O
TTa
EVENTOUT
ADC_IN14
25
H6
-
-
-
PC5
I/O
TTa
TSC_G3_IO1
ADC_IN15
TTa
TIM3_CH3,
TIM1_CH2N,
TSC_G3_IO2,
EVENTOUT
ADC_IN8
TIM3_CH4,
TIM14_CH1,
TIM1_CH3N,
TSC_G3_IO3
ADC_IN9
TSC_G3_IO4
-
FT
I2C2_SCL,
CEC,
TIM2_CH3,
TSC_SYNC
-
FT
I2C2_SDA,
TIM2_CH4,
TSC_G6_IO1,
EVENTOUT
-
26
F5
18
14
14
PB0
I/O
27
G5
19
15
15
PB1
I/O
TTa
28
G6
20
-
16
PB2
I/O
FT
29
G7
21
-
-
PB10
I/O
(3)
30
H7
22
-
-
PB11
I/O
31
D4
23
16
0
VSS
S
Ground
32
E4
24
17
17
VDD
S
Digital power supply
DocID022265 Rev 4
33/115
36
Pinouts and pin descriptions
STM32F051xx
Table 13. Pin definitions (continued)
Pin functions
I/O structure
Pin name
(function after
reset)
Pin type
UFQFPN32
LQFP32
LQFP48/UFQFPN48
UFBGA64
LQFP64
Pin number
Notes
Alternate functions
Additional functions
-
33
H8
25
-
-
PB12
I/O
FT
SPI2_NSS,
TIM1_BKIN,
TSC_G6_IO2,
EVENTOUT
34
G8
26
-
-
PB13
I/O
FT
SPI2_SCK,
TIM1_CH1N,
TSC_G6_IO3
-
FT
SPI2_MISO,
TIM1_CH2N,
TIM15_CH1,
TSC_G6_IO4
-
RTC_REFIN
35
F8
27
-
-
PB14
I/O
36
F7
28
-
-
PB15
I/O
FT
SPI2_MOSI,
TIM1_CH3N,
TIM15_CH1N,
TIM15_CH2
37
F6
-
-
-
PC6
I/O
FT
TIM3_CH1
-
38
E7
-
-
-
PC7
I/O
FT
TIM3_CH2
-
39
E8
-
-
-
PC8
I/O
FT
TIM3_CH3
-
40
D8
-
-
-
PC9
I/O
FT
TIM3_CH4
-
FT
USART1_CK,
TIM1_CH1,
EVENTOUT,
MCO
-
FT
USART1_TX,
TIM1_CH2,
TIM15_BKIN,
TSC_G4_IO1
-
FT
USART1_RX,
TIM1_CH3,
TIM17_BKIN,
TSC_G4_IO2
-
FT
USART1_CTS,
TIM1_CH4,
COMP1_OUT,
TSC_G4_IO3,
EVENTOUT
-
41
42
43
44
D7
C7
C6
C8
34/115
29
30
31
32
18
19
20
21
18
19
20
21
PA8
PA9
PA10
PA11
I/O
I/O
I/O
I/O
DocID022265 Rev 4
STM32F051xx
Pinouts and pin descriptions
Table 13. Pin definitions (continued)
Pin functions
I/O structure
Pin name
(function after
reset)
Pin type
UFQFPN32
LQFP32
LQFP48/UFQFPN48
UFBGA64
LQFP64
Pin number
Notes
Alternate functions
Additional functions
USART1_RTS,
TIM1_ETR,
COMP2_OUT,
TSC_G4_IO4,
EVENTOUT
-
IR_OUT,
SWDIO
-
45
B8
33
22
22
PA12
I/O
FT
46
A8
34
23
23
PA13
(SWDIO)
I/O
FT
47
D6
35
-
-
PF6
I/O
FTf
I2C2_SCL
-
48
E6
36
-
-
PF7
I/O
FTf
I2C2_SDA
-
49
A7
37
24
24
PA14
(SWCLK)
I/O
FT
USART2_TX,
SWCLK
-
SPI1_NSS,
I2S1_WS,
USART2_RX,
TIM2_CH1_ETR,
EVENTOUT
-
(4)
(4)
50
A6
38
25
25
PA15
I/O
FT
51
B7
-
-
-
PC10
I/O
FT
-
52
B6
-
-
-
PC11
I/O
FT
-
53
C5
-
-
-
PC12
I/O
FT
-
54
B5
-
-
-
PD2
I/O
FT
TIM3_ETR
-
FT
SPI1_SCK,
I2S1_CK,
TIM2_CH2,
TSC_G5_IO1,
EVENTOUT
-
FT
SPI1_MISO,
I2S1_MCK,
TIM3_CH1,
TSC_G5_IO2,
EVENTOUT
-
FT
SPI1_MOSI,
I2S1_SD,
I2C1_SMBA,
TIM16_BKIN,
TIM3_CH2
-
55
56
57
A5
A4
C4
39
40
41
26
27
28
26
27
28
PB3
PB4
PB5
I/O
I/O
I/O
DocID022265 Rev 4
35/115
36
Pinouts and pin descriptions
STM32F051xx
Table 13. Pin definitions (continued)
Pin functions
58
D3
42
29
29
PB6
I/O
I/O structure
Pin name
(function after
reset)
Pin type
UFQFPN32
LQFP32
LQFP48/UFQFPN48
UFBGA64
LQFP64
Pin number
Alternate functions
Additional functions
FTf
I2C1_SCL,
USART1_TX,
TIM16_CH1N,
TSC_G5_IO3
-
I2C1_SDA,
USART1_RX,
TIM17_CH1N,
TSC_G5_IO4
-
59
C3
43
30
30
PB7
I/O
FTf
60
B4
44
31
31
BOOT0
I
B
61
B3
45
-
32
PB8
I/O
Notes
FTf
Boot memory selection
(4)
FTf
I2C1_SCL,
CEC,
TIM16_CH1,
TSC_SYNC
-
I2C1_SDA,
IR_OUT,
TIM17_CH1,
EVENTOUT
-
62
A3
46
-
-
PB9
I/O
63
D5
47
32
0
VSS
S
Ground
64
E5
48
1
1
VDD
S
Digital power supply
1. PC13, PC14 and PC15 are supplied through the power switch. Since the switch only sinks a limited amount of
current (3 mA), the use of GPIOs PC13 to PC15 in output mode is limited:
- The speed should not exceed 2 MHz with a maximum load of 30 pF.
- These GPIOs must not be used as current sources (e.g. to drive an LED).
2. After the first RTC domain power-up, PC13, PC14 and PC15 operate as GPIOs. Their function then depends
on the content of the RTC registers which are not reset by the main reset. For details on how to manage these
GPIOs, refer to the RTC domain and RTC register descriptions in the reference manual.
3. On the LQFP32 package, PB2 and PB8 should be treated as unconnected pins (even when they are not
available on the package, they are not forced to a defined level by hardware).
4. After reset, these pins are configured as SWDIO and SWCLK alternate functions, and the internal pull-up on
the SWDIO pin and the internal pull-down on the SWCLK pin are activated.
36/115
DocID022265 Rev 4
Pin name
AF0
PA0
AF1
AF2
AF3
USART2_CTS
TIM2_CH1_ETR
TSC_G1_IO1
AF4
AF5
AF6
AF7
COMP1_OUT
DocID022265 Rev 4
PA1
EVENTOUT
USART2_RTS
TIM2_CH2
TSC_G1_IO2
PA2
TIM15_CH1
USART2_TX
TIM2_CH3
TSC_G1_IO3
PA3
TIM15_CH2
USART2_RX
TIM2_CH4
TSC_G1_IO4
PA4
SPI1_NSS, I2S1_WS
USART2_CK
PA5
SPI1_SCK, I2S1_CK
CEC
TIM2_CH1_ETR
TSC_G2_IO2
PA6
SPI1_MISO, I2S1_MCK
TIM3_CH1
TIM1_BKIN
TSC_G2_IO3
PA7
SPI1_MOSI, I2S1_SD
TIM3_CH2
TIM1_CH1N
TSC_G2_IO4
PA8
MCO
USART1_CK
TIM1_CH1
EVENTOUT
PA9
TIM15_BKIN
USART1_TX
TIM1_CH2
TSC_G4_IO1
PA10
TIM17_BKIN
USART1_RX
TIM1_CH3
TSC_G4_IO2
PA11
EVENTOUT
USART1_CTS
TIM1_CH4
TSC_G4_IO3
COMP1_OUT
PA12
EVENTOUT
USART1_RTS
TIM1_ETR
TSC_G4_IO4
COMP2_OUT
PA13
SWDIO
IR_OUT
PA14
SWCLK
USART2_TX
PA15
SPI1_NSS, I2S1_WS
USART2_RX
TIM2_CH1_ETR
EVENTOUT
TSC_G2_IO1
COMP2_OUT
TIM14_CH1
TIM14_CH1
TIM16_CH1
EVENTOUT
COMP1_OUT
TIM17_CH1
EVENTOUT
COMP2_OUT
STM32F051xx
Table 14. Alternate functions selected through GPIOA_AFR registers for port A
37/115
STM32F051xx
Table 15. Alternate functions selected through GPIOB_AFR registers for port B
Pin
name
AF0
AF1
AF2
AF3
PB0
EVENTOUT
TIM3_CH3
TIM1_CH2N
TSC_G3_IO2
PB1
TIM14_CH1
TIM3_CH4
TIM1_CH3N
TSC_G3_IO3
PB2
TSC_G3_IO4
PB3
SPI1_SCK, I2S1_CK
EVENTOUT
TIM2_CH2
TSC_G5_IO1
PB4
SPI1_MISO, I2S1_MCK
TIM3_CH1
EVENTOUT
TSC_G5_IO2
PB5
SPI1_MOSI, I2S1_SD
TIM3_CH2
TIM16_BKIN
I2C1_SMBA
PB6
USART1_TX
I2C1_SCL
TIM16_CH1N
TSC_G5_IO3
PB7
USART1_RX
I2C1_SDA
TIM17_CH1N
TSC_G5_IO4
PB8
CEC
I2C1_SCL
TIM16_CH1
TSC_SYNC
PB9
IR_OUT
I2C1_SDA
TIM17_CH1
EVENTOUT
PB10
CEC
I2C2_SCL
TIM2_CH3
TSC_SYNC
PB11
EVENTOUT
I2C2_SDA
TIM2_CH4
TSC_G6_IO1
PB12
SPI2_NSS
EVENTOUT
TIM1_BKIN
TSC_G6_IO2
PB13
SPI2_SCK
TIM1_CH1N
TSC_G6_IO3
PB14
SPI2_MISO
TIM15_CH1
TIM1_CH2N
TSC_G6_IO4
PB15
SPI2_MOSI
TIM15_CH2
TIM1_CH3N
TIM15_CH1N
38/115
DocID022265 Rev 4
STM32F051xx
5
Memory mapping
Memory mapping
Figure 9. STM32F051xx memory map
[))))))))
[))
$+%
[
[(
[(
&RUWH[ 0,QWHUQDO 3HULSKHUDOV
UHVHUYHG
[&
[))
$+%
[
UHVHUYHG
[$
[
[)))))))
[))))&
[))))
[
$3%
UHVHUYHG
2SWLRQ%\WHV
[
UHVHUYHG
6\VWHPPHPRU\
[
[)))(&
$3%
[
[
UHVHUYHG
[
3HULSKHUDOV
[
)ODVKPHPRU\
[
65$0
[
UHVHUYHG
&2'(
[
)ODVKV\VWHPPHPRU\
RU65$0GHSHQGLQJRQ
%227FRQILJXUDWLRQ
[
[
5HVHUYHG
069
DocID022265 Rev 4
39/115
41
Memory mapping
STM32F051xx
Table 16. STM32F051xx peripheral register boundary addresses
Bus
AHB2
AHB1
APB
40/115
Boundary address
Size
Peripheral
0x4800 1800 - 0x5FFF FFFF
~384 MB
Reserved
0x4800 1400 - 0x4800 17FF
1 KB
GPIOF
0x4800 1000 - 0x4800 13FF
1 KB
Reserved
0x4800 0C00 - 0x4800 0FFF
1 KB
GPIOD
0x4800 0800 - 0x4800 0BFF
1 KB
GPIOC
0x4800 0400 - 0x4800 07FF
1 KB
GPIOB
0x4800 0000 - 0x4800 03FF
1 KB
GPIOA
0x4002 4400 - 0x47FF FFFF
~128 MB
Reserved
0x4002 4000 - 0x4002 43FF
1 KB
TSC
0x4002 3400 - 0x4002 3FFF
3 KB
Reserved
0x4002 3000 - 0x4002 33FF
1 KB
CRC
0x4002 2400 - 0x4002 2FFF
3 KB
Reserved
0x4002 2000 - 0x4002 23FF
1 KB
FLASH Interface
0x4002 1400 - 0x4002 1FFF
3 KB
Reserved
0x4002 1000 - 0x4002 13FF
1 KB
RCC
0x4002 0400 - 0x4002 0FFF
3 KB
Reserved
0x4002 0000 - 0x4002 03FF
1 KB
DMA
0x4001 8000 - 0x4001 FFFF
32 KB
Reserved
0x4001 5C00 - 0x4001 7FFF
9 KB
Reserved
0x4001 5800 - 0x4001 5BFF
1 KB
DBGMCU
0x4001 4C00 - 0x4001 57FF
3 KB
Reserved
0x4001 4800 - 0x4001 4BFF
1 KB
TIM17
0x4001 4400 - 0x4001 47FF
1 KB
TIM16
0x4001 4000 - 0x4001 43FF
1 KB
TIM15
0x4001 3C00 - 0x4001 3FFF
1 KB
Reserved
0x4001 3800 - 0x4001 3BFF
1 KB
USART1
0x4001 3400 - 0x4001 37FF
1 KB
Reserved
0x4001 3000 - 0x4001 33FF
1 KB
SPI1/I2S1
0x4001 2C00 - 0x4001 2FFF
1 KB
TIM1
0x4001 2800 - 0x4001 2BFF
1 KB
Reserved
0x4001 2400 - 0x4001 27FF
1 KB
ADC
0x4001 0800 - 0x4001 23FF
7 KB
Reserved
0x4001 0400 - 0x4001 07FF
1 KB
EXTI
0x4001 0000 - 0x4001 03FF
1 KB
SYSCFG + COMP
0x4000 8000 - 0x4000 FFFF
32 KB
Reserved
DocID022265 Rev 4
STM32F051xx
Memory mapping
Table 16. STM32F051xx peripheral register boundary addresses (continued)
Bus
APB
Boundary address
Size
Peripheral
0x4000 7C00 - 0x4000 7FFF
1 KB
Reserved
0x4000 7800 - 0x4000 7BFF
1 KB
CEC
0x4000 7400 - 0x4000 77FF
1 KB
DAC
0x4000 7000 - 0x4000 73FF
1 KB
PWR
0x4000 5C00 - 0x4000 6FFF
5 KB
Reserved
0x4000 5800 - 0x4000 5BFF
1 KB
I2C2
0x4000 5400 - 0x4000 57FF
1 KB
I2C1
0x4000 4800 - 0x4000 53FF
3 KB
Reserved
0x4000 4400 - 0x4000 47FF
1 KB
USART2
0x4000 3C00 - 0x4000 43FF
2 KB
Reserved
0x4000 3800 - 0x4000 3BFF
1 KB
SPI2
0x4000 3400 - 0x4000 37FF
1 KB
Reserved
0x4000 3000 - 0x4000 33FF
1 KB
IWDG
0x4000 2C00 - 0x4000 2FFF
1 KB
WWDG
0x4000 2800 - 0x4000 2BFF
1 KB
RTC
0x4000 2400 - 0x4000 27FF
1 KB
Reserved
0x4000 2000 - 0x4000 23FF
1 KB
TIM14
0x4000 1400 - 0x4000 1FFF
3 KB
Reserved
0x4000 1000 - 0x4000 13FF
1 KB
TIM6
0x4000 0800 - 0x4000 0FFF
2 KB
Reserved
0x4000 0400 - 0x4000 07FF
1 KB
TIM3
0x4000 0000 - 0x4000 03FF
1 KB
TIM2
DocID022265 Rev 4
41/115
41
Electrical characteristics
STM32F051xx
6
Electrical characteristics
6.1
Parameter conditions
Unless otherwise specified, all voltages are referenced to VSS.
6.1.1
Minimum and maximum values
Unless otherwise specified, the minimum and maximum values are guaranteed in the worst
conditions of ambient temperature, supply voltage and frequencies by tests in production on
100% of the devices with an ambient temperature at TA = 25 °C and TA = TAmax (given by
the selected temperature range).
Data based on characterization results, design simulation and/or technology characteristics
are indicated in the table footnotes and are not tested in production. Based on
characterization, the minimum and maximum values refer to sample tests and represent the
mean value plus or minus three times the standard deviation (mean ±3).
6.1.2
Typical values
Unless otherwise specified, typical data are based on TA = 25 °C, VDD = VDDA = 3.3 V. They
are given only as design guidelines and are not tested.
Typical ADC accuracy values are determined by characterization of a batch of samples from
a standard diffusion lot over the full temperature range, where 95% of the devices have an
error less than or equal to the value indicated (mean ±2).
6.1.3
Typical curves
Unless otherwise specified, all typical curves are given only as design guidelines and are
not tested.
6.1.4
Loading capacitor
The loading conditions used for pin parameter measurement are shown in Figure 10.
6.1.5
Pin input voltage
The input voltage measurement on a pin of the device is described in Figure 11.
Figure 10. Pin loading conditions
Figure 11. Pin input voltage
-#5PIN
-#5PIN
& S)
6).
-36
42/115
DocID022265 Rev 4
-36
STM32F051xx
6.1.6
Electrical characteristics
Power supply scheme
Figure 12. Power supply scheme
9%$7
%DFNXSFLUFXLWU\
/6(57&
%DFNXSUHJLVWHUV
±9
3RZHUVZLWFK
9''
9&25(
[9''
5HJXODWRU
287
[Q)
*3,2V
,1
[—)
/HYHOVKLIWHU
9'',2
,2
ORJLF
.HUQHOORJLF
&38'LJLWDO
0HPRULHV
[966
9''$
9''$
Q)
—)
95()
95()
$'&
'$&
$QDORJ
5&V3//«
966$
06Y9
Caution:
Each power supply pair (VDD/VSS, VDDA/VSSA etc.) must be decoupled with filtering ceramic
capacitors as shown above. These capacitors must be placed as close as possible to, or
below, the appropriate pins on the underside of the PCB to ensure the good functionality of
the device.
DocID022265 Rev 4
43/115
94
Electrical characteristics
6.1.7
STM32F051xx
Current consumption measurement
Figure 13. Current consumption measurement scheme
*
%%@7#"5
6"!4
)$$
6$$
)$$!
6$$!
-36
6.2
Absolute maximum ratings
Stresses above the absolute maximum ratings listed in Table 17: Voltage characteristics,
Table 18: Current characteristics, and Table 19: Thermal characteristics may cause
permanent damage to the device. These are stress ratings only and functional operation of
the device at these conditions is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
Table 17. Voltage characteristics(1)
Symbol
Ratings
Min
Max
Unit
–0.3
4.0
V
-
0.4
V
Input voltage on FT and FTf pins
VSS  0.3
VDDIOx + 4.0
V
Input voltage on TTa pins
VSS  0.3
4.0
V
Input voltage on any other pin
VSS 0.3
4.0
V
Variations between different VDD power pins
-
50
mV
Variations between all the different ground
pins
-
50
mV
VDDx–VSS
External main supply voltage
(including VDDA, VDD and VBAT)
VDD–VDDA
Allowed voltage difference for VDD > VDDA
VIN(2)
|VDDx|
|VSSx VSS|
VESD(HBM)
Electrostatic discharge voltage
(human body model)
see Section 6.3.12: Electrical
sensitivity characteristics
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power
supply, in the permitted range.
2. VIN maximum must always be respected. Refer to Table 18: Current characteristics for the maximum
allowed injected current values.
44/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 18. Current characteristics
Symbol
Ratings
Max.
Unit
mA
IVDD
Total current into sum of all VDD power lines (source)(1)
120
IVSS
(1)
-120
Total current out of sum of all VSS ground lines (sink)
IVDD(PIN)
(1)
Maximum current into each VDD power pin (source)
100
IVSS(PIN)
Maximum current out of each VSS ground pin (sink)(1)
-100
IIO(PIN)
IIO(PIN)
Output current sunk by any I/O and control pin
25
Output current source by any I/O and control pin
Total output current sunk by sum of all IOs and control pins
-25
(2)
Total output current sourced by sum of all IOs and control pins(2)
Injected current on FT, FTf and B pins
IINJ(PIN)(3)
Injected current on TC and RST pin
(5)
IINJ(PIN)
80
-80
-5/+0(4)
±5
Injected current on TTa pins
±5
Total injected current (sum of all I/O and control pins)(6)
± 25
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power supply, in the
permitted range.
2. This current consumption must be correctly distributed over all I/Os and control pins. The total output current must not be
sunk/sourced between two consecutive power supply pins referring to high pin count QFP packages.
3. A positive injection is induced by VIN > VDDIOx while a negative injection is induced by VIN < VSS. IINJ(PIN) must never be
exceeded. Refer to Table 17: Voltage characteristics for the maximum allowed input voltage values.
4. Positive injection is not possible on these I/Os and does not occur for input voltages lower than the specified maximum
value.
5. On these I/Os, a positive injection is induced by VIN > VDDA. Negative injection disturbs the analog performance of the
device. See note (2) below Table 55: ADC accuracy.
6. When several inputs are submitted to a current injection, the maximum IINJ(PIN) is the absolute sum of the positive and
negative injected currents (instantaneous values).
Table 19. Thermal characteristics
Symbol
TSTG
TJ
Ratings
Storage temperature range
Maximum junction temperature
DocID022265 Rev 4
Value
Unit
–65 to +150
°C
150
°C
45/115
94
Electrical characteristics
STM32F051xx
6.3
Operating conditions
6.3.1
General operating conditions
Table 20. General operating conditions
Symbol
Parameter
Conditions
Min
Max
fHCLK
Internal AHB clock frequency
0
48
fPCLK
Internal APB clock frequency
0
48
VDD
Standard operating voltage
2
3.6
2
3.6
2.4
3.6
1.65
3.6
TC and RST I/O
–0.3
VDDIOx+0.3
TTa I/O
–0.3
VDDA+0.3
FT and FTf I/O
–0.3
5.5(1)
BOOT0
0
9.0
LQFP64
-
444
LQFP48
-
364
LQFP32
-
357
UFQFPN32
-
526
UFQFPN48
-
625
UFBGA64
-
308
–40
85
–40
105
VDDA
VBAT
VIN
PD
Analog operating voltage
(ADC and DAC not used)
Analog operating voltage
(ADC and DAC used)
Backup operating voltage
I/O input voltage
Power dissipation at TA = 85 °C
for suffix 6 or TA = 105 °C for
suffix 7(2)
Maximum power dissipation
Ambient temperature for the
suffix 7 version
Maximum power dissipation
–40
105
Low power dissipation(3)
–40
125
Suffix 6 version
–40
105
Suffix 7 version
–40
125
Junction temperature range
Low power
dissipation(3)
MHz
V
V
Ambient temperature for the
suffix 6 version
TA
TJ
Must have a potential equal
to or higher than VDD
Unit
V
V
mW
°C
°C
°C
1. To sustain a voltage higher than VDDIOx+0.3 V, the internal pull-up/pull-down resistors must be disabled.
2. If TA is lower, higher PD values are allowed as long as TJ does not exceed TJmax.
3. In low power dissipation state, TA can be extended to this range as long as TJ does not exceed TJmax (see Section 7.2:
Thermal characteristics).
46/115
DocID022265 Rev 4
STM32F051xx
6.3.2
Electrical characteristics
Operating conditions at power-up / power-down
The parameters given in Table 21 are derived from tests performed under the ambient
temperature condition summarized in Table 20.
Table 21. Operating conditions at power-up / power-down
Symbol
Parameter
tVDD
tVDDA
6.3.3
Conditions
Min
Max
VDD rise time rate
0

VDD fall time rate
20

VDDA rise time rate
0

VDDA fall time rate
20

Unit
μs/V
Embedded reset and power control block characteristics
The parameters given in Table 22 are derived from tests performed under the ambient
temperature and supply voltage conditions summarized in Table 20: General operating
conditions.
Table 22. Embedded reset and power control block characteristics
Symbol
VPOR/PDR(1)
VPDRhyst
tRSTTEMPO(4)
Parameter
Power on/power down
reset threshold
Conditions
Min
Typ
Max
Unit
Falling edge(2)
1.80
1.88
1.96(3)
V
1.84(3)
1.92
2.00
V
-
40
-
mV
1.50
2.50
4.50
ms
Rising edge
PDR hysteresis
Reset temporization
1. The PDR detector monitors VDD and also VDDA (if kept enabled in the option bytes). The POR detector
monitors only VDD.
2. The product behavior is guaranteed by design down to the minimum VPOR/PDR value.
3. Data based on characterization results, not tested in production.
4. Guaranteed by design, not tested in production.
Table 23. Programmable voltage detector characteristics
Symbol
Parameter
VPVD0
PVD threshold 0
VPVD1
PVD threshold 1
VPVD2
PVD threshold 2
VPVD3
PVD threshold 3
Conditions
Min
Typ
Max
Unit
Rising edge
2.1
2.18
2.26
V
Falling edge
2
2.08
2.16
V
Rising edge
2.19
2.28
2.37
V
Falling edge
2.09
2.18
2.27
V
Rising edge
2.28
2.38
2.48
V
Falling edge
2.18
2.28
2.38
V
Rising edge
2.38
2.48
2.58
V
Falling edge
2.28
2.38
2.48
V
DocID022265 Rev 4
47/115
94
Electrical characteristics
STM32F051xx
Table 23. Programmable voltage detector characteristics (continued)
Symbol
Parameter
Min
Typ
Max
Unit
Rising edge
2.47
2.58
2.69
V
Falling edge
2.37
2.48
2.59
V
Rising edge
2.57
2.68
2.79
V
Falling edge
2.47
2.58
2.69
V
Rising edge
2.66
2.78
2.9
V
Falling edge
2.56
2.68
2.8
V
Rising edge
2.76
2.88
3
V
Falling edge
2.66
2.78
2.9
V
PVD hysteresis
-
100
-
mV
PVD current consumption
-
0.15
0.26(1)
μA
VPVD4
PVD threshold 4
VPVD5
PVD threshold 5
VPVD6
PVD threshold 6
VPVD7
PVD threshold 7
VPVDhyst
(1)
IDD(PVD)
Conditions
1. Guaranteed by design, not tested in production.
6.3.4
Embedded reference voltage
The parameters given in Table 24 are derived from tests performed under the ambient
temperature and supply voltage conditions summarized in Table 20: General operating
conditions.
Table 24. Embedded internal reference voltage
Symbol
Parameter
VREFINT
Internal reference voltage
TS_vrefint (2)
ADC sampling time when
reading the internal
reference voltage
VREFINT
Internal reference voltage
spread over the
temperature range
TCoeff
Conditions
Min
Typ
Max
Unit
–40 °C < TA < +105 °C
1.16
1.2
1.25
V
1.16
1.2
1.24(1)
V
17.1(3)
-
-
μs
-
-
10(3)
mV
-
-
100(3) ppm/°C
–40 °C < TA < +85 °C
VDDA = 3 V
Temperature coefficient
1. Data based on characterization results, not tested in production.
2. The shortest sampling time can be determined in the application by multiple iterations.
3. Guaranteed by design, not tested in production.
48/115
DocID022265 Rev 4
STM32F051xx
6.3.5
Electrical characteristics
Supply current characteristics
The current consumption is a function of several parameters and factors such as the
operating voltage, ambient temperature, I/O pin loading, device software configuration,
operating frequencies, I/O pin switching rate, program location in memory and executed
binary code.
The current consumption is measured as described in Figure 13: Current consumption
measurement scheme.
All Run-mode current consumption measurements given in this section are performed with a
reduced code that gives a consumption equivalent to CoreMark code.
Typical and maximum current consumption
The MCU is placed under the following conditions:

All I/O pins are in analog input mode

All peripherals are disabled except when explicitly mentioned

The Flash memory access time is adjusted to the fHCLK frequency:
–
0 wait state and Prefetch OFF from 0 to 24 MHz
–
1 wait state and Prefetch ON above 24 MHz

When the peripherals are enabled fPCLK = fHCLK
The parameters given in Table 25 to Table 28 are derived from tests performed under
ambient temperature and supply voltage conditions summarized in Table 20: General
operating conditions.
DocID022265 Rev 4
49/115
94
Electrical characteristics
STM32F051xx
Table 25. Typical and maximum current consumption from the VDD supply at VDD = 3.6
All peripherals enabled
Symbol Parameter Conditions
HSE
bypass,
PLL on
Supply
current in
Run mode,
code
executing
from Flash
HSE
bypass,
PLL off
HSI clock,
PLL on
HSI clock,
PLL off
HSE
bypass,
PLL on
IDD
Supply
current in
Run mode,
code
executing
from RAM
HSE
bypass,
PLL off
HSI clock,
PLL on
HSI clock,
PLL off
Supply
current in
Sleep
mode,
code
executing
from Flash
or RAM
HSE
bypass,
PLL on
HSE
bypass,
PLL off
HSI clock,
PLL on
HSI clock,
PLL off
fHCLK
Max @ TA(1)
Typ
All peripherals disabled
Max @ TA(1)
Typ
25 °C
85 °C
105 °C
48 MHz 22.0
22.8
22.8
23.8
32 MHz 15.0
15.5
15.5
24 MHz 12.2
13.2
8 MHz
4.4
1 MHz
Unit
25 °C
85 °C
105 °C
11.8
12.7
12.7
13.3
16.0
7.6
8.7
8.7
9.0
13.2
13.6
7.2
7.9
7.9
8.1
5.2
5.2
5.4
2.7
2.9
2.9
3.0
1.0
1.3
1.3
1.4
0.7
0.9
0.9
0.9
48 MHz 22.0
22.8
22.8
23.8
11.8
12.7
12.7
13.3
32 MHz 15.0
15.5
15.5
16.0
7.6
8.7
8.7
9.0
24 MHz 12.2
13.2
13.2
13.6
7.2
7.9
7.9
8.1
8 MHz
5.2
5.2
5.4
2.7
2.9
2.9
3.0
48 MHz 22.2 23.2(2)
23.2
24.4(2)
12.0 12.7(2)
12.7
13.3(2)
32 MHz 15.4
16.3
16.3
16.8
7.8
8.7
8.7
9.0
24 MHz 11.2
12.2
12.2
12.8
6.2
7.9
7.9
8.1
8 MHz
4.0
4.5
4.5
4.7
1.9
2.9
2.9
3.0
1 MHz
0.6
0.8
0.8
0.9
0.3
0.6
0.6
0.7
48 MHz 22.2
23.2
23.2
24.4
12.0
12.7
12.7
13.3
32 MHz 15.4
16.3
16.3
16.8
7.8
8.7
8.7
9.0
24 MHz 11.2
12.2
12.2
12.8
6.2
7.9
7.9
8.1
8 MHz
4.5
4.5
4.7
1.9
2.9
2.9
3.0
48 MHz 14.0 15.3(2)
15.3
16.0(2)
2.8
3.0(2)
3.0
3.2(2)
32 MHz
9.5
10.2
10.2
10.7
2.0
2.1
2.1
2.3
24 MHz
7.3
7.8
7.8
8.3
1.5
1.7
1.7
1.9
8 MHz
2.6
2.9
2.9
3.0
0.6
0.8
0.8
0.8
1 MHz
0.4
0.6
0.6
0.6
0.2
0.4
0.4
0.4
48 MHz 14.0
15.3
15.3
16.0
3.8
4.0
4.1
4.2
32 MHz
9.5
10.2
10.2
10.7
2.6
2.7
2.8
2.8
24 MHz
7.3
7.8
7.8
8.3
2.0
2.1
2.1
2.1
8 MHz
2.6
2.9
2.9
3.0
0.6
0.8
0.8
0.8
4.4
4.0
1. Data based on characterization results, not tested in production unless otherwise specified.
2. Data based on characterization results and tested in production (using one common test limit for sum of IDD and IDDA).
50/115
DocID022265 Rev 4
mA
STM32F051xx
Electrical characteristics
Table 26. Typical and maximum current consumption from the VDDA supply
VDDA = 2.4 V
Symbol Parameter
Conditions
(1)
VDDA = 3.6 V
Max @ TA(2)
fHCLK
Max @ TA(2)
Typ
25 °C
IDDA
Supply
current in
Run or
Sleep
mode,
code
executing
from Flash
or RAM
HSE
bypass,
PLL on
HSE
bypass,
PLL off
HSI clock,
PLL on
HSI clock,
PLL off
Unit
Typ
85 °C 105 °C
25 °C
85 °C 105 °C
48 MHz
150
170(3)
178
182(3)
164
183(3)
195
198(3)
32 MHz
104
121
126
128
113
129
135
138
24 MHz
82
96
100
103
88
102
106
108
8 MHz
2.0
2.7
3.1
3.3
3.5
3.8
4.1
4.4
1 MHz
2.0
2.7
3.1
3.3
3.5
3.8
4.1
4.4
48 MHz
220
240
248
252
244
263
275
278
32 MHz
174
191
196
198
193
209
215
218
24 MHz
152
167
173
174
168
183
190
192
8 MHz
72
79
82
83
83.5
91
94
95
µA
1. Current consumption from the VDDA supply is independent of whether the digital peripherals are enabled or disabled, being
in Run or Sleep mode or executing from Flash or RAM. Furthermore, when the PLL is off, IDDA is independent from the
frequency.
2. Data based on characterization results, not tested in production unless otherwise specified.
3. Data based on characterization results and tested in production (using one common test limit for sum of IDD and IDDA).
DocID022265 Rev 4
51/115
94
Electrical characteristics
STM32F051xx
Table 27. Typical and maximum current consumption in Stop and Standby modes
Parameter
IDD
Supply
current
in
Standby
mode
Supply
current
in Stop
mode
IDDA
Supply
current
in
Standby
mode
Supply
current
in Stop
mode
Supply
current
in
Standby
mode
2.0 V 2.4 V
Regulator in run
mode, all oscillators
OFF
2.7 V
3.0 V 3.3 V 3.6 V
TA =
TA = TA =
25 °C 85 °C 105 °C
15
15.1
15.25 15.45
15.7
16
22(2)
48
64(2)
Regulator in lowpower mode, all
oscillators OFF
3.15
3.25
3.35
3.45
3.7
4
(2)
32
45(2)
LSI ON and IWDG
ON
0.8
0.95
1.05
1.2
1.35
1.5
-
-
-
LSI OFF and IWDG
OFF
0.65
0.75
0.85
0.95
1.1
1.3
2(2)
2.5
3(2)
Regulator in run
mode, all
oscillators OFF
1.85
2
2.15
2.3
2.45
2.6
3.5(2)
3.5
4.5(2)
Regulator in lowpower mode, all 1.85
oscillators OFF
2
2.15
2.3
2.45
2.6
3.5(2)
3.5
4.5(2)
VDDA monitoring ON
Supply
current
in Stop
mode
Conditions
VDDA monitoring OFF
Symbol
Max(1)
Typ @VDD (VDD = VDDA)
μA
LSI ON and
IWDG ON
2.25
2.5
2.65
2.85
3.05
3.3
-
-
-
LSI OFF and
IWDG OFF
1.75
1.9
2
2.15
2.3
2.5
3.5(2)
3.5
4.5(2)
Regulator in run
mode, all
oscillators OFF
1.11
1.15
1.18
1.22
1.27
1.35
-
-
-
Regulator in lowpower mode, all
oscillators OFF
1.11
1.15
1.18
1.22
1.27
1.35
-
-
-
LSI ON and
IWDG ON
1.5
1.58
1.65
1.78
1.91
2.04
-
-
-
LSI OFF and
IWDG OFF
1
1.02
1.05
1.05
1.15
1.22
-
-
-
1. Data based on characterization results, not tested in production unless otherwise specified.
2. Data based on characterization results and tested in production (using one common test limit for sum of IDD and IDDA).
52/115
Unit
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 28. Typical and maximum current consumption from the VBAT supply
Max(1)
RTC
domain
IDD_VBAT
supply
current
= 3.6 V
= 3.3 V
= 2.7 V
Conditions
= 2.4 V
Parameter
= 1.8 V
Symbol
= 1.65 V
Typ @ VBAT
LSE & RTC ON; “Xtal
mode”: lower driving
capability;
LSEDRV[1:0] = '00'
0.41 0.43 0.53 0.58 0.71 0.80
LSE & RTC ON; “Xtal
mode” higher driving
capability;
LSEDRV[1:0] = '11'
0.71 0.75 0.85 0.91 1.06 1.16
TA =
25 °C
0.85
TA =
TA =
85 °C 105 °C
1.1
Unit
1.5
μA
1.25
1.55
2
1. Data based on characterization results, not tested in production.
Typical current consumption
The MCU is placed under the following conditions:

VDD=VDDA=3.3 V

All I/O pins are in analog input configuration

The Flash access time is adjusted to fHCLK frequency:
–
0 wait state and Prefetch OFF from 0 to 24 MHz
–
1 wait state and Prefetch ON above 24 MHz

When the peripherals are enabled, fPCLK = fHCLK

PLL is used for frequencies greater than 8 MHz

AHB prescaler of 2, 4, 8 and 16 is used for the frequencies 4 MHz, 2 MHz, 1 MHz and
500 kHz respectively
DocID022265 Rev 4
53/115
94
Electrical characteristics
STM32F051xx
Table 29. Typical current consumption in Run mode, code with data processing
running from Flash
Typ
Symbol
IDD
Parameter
Conditions
Supply current in Run
mode from VDD
supply
Running from
HSE crystal
clock 8 MHz,
code
executing
from Flash
IDDA
54/115
Supply current in Run
mode from VDDA
supply
fHCLK
Peripherals
enabled
Peripherals
disabled
48 MHz
23.3
11.5
36 MHz
17.6
9.0
32 MHz
15.9
8.0
24 MHz
12.4
7.5
16 MHz
8.5
5.2
8 MHz
4.5
3.0
4 MHz
2.8
1.9
2 MHz
1.7
1.3
1 MHz
1.3
1.0
500 kHz
1.0
0.9
48 MHz
158
158
36 MHz
120
120
32 MHz
108
108
24 MHz
83
83
16 MHz
60
60
8 MHz
2.43
2.43
4 MHz
2.43
2.43
2 MHz
2.43
2.43
1 MHz
2.43
2.43
500 kHz
2.43
2.43
DocID022265 Rev 4
Unit
mA
μA
STM32F051xx
Electrical characteristics
Table 30. Typical current consumption in Sleep mode, code running from Flash or
RAM
Typ
Symbol
IDD
Parameter
Conditions
Supply current in
Sleep mode from VDD
supply
Peripherals Peripherals
enabled
disabled
48 MHz
13.9
2.98
36 MHz
10.55
2.84
32 MHz
9.6
2.6
24 MHz
7.23
2.09
16 MHz
5.01
1.58
8 MHz
Running from
HSE crystal
clock 8 MHz,
code executing
from Flash or
RAM
IDDA
fHCLK
Supply current in
Sleep mode from
VDDA supply
DocID022265 Rev 4
0.99
4 MHz
1.81
0.85
2 MHz
1.27
0.77
1 MHz
1.03
0.73
500 kHz
0.9
0.71
125 kHz
0.78
0.69
48 MHz
158
157
36 MHz
119
119
32 MHz
108
107
24 MHz
83
83
16 MHz
60
60
8 MHz
2.36
2.38
4 MHz
2.36
2.38
2 MHz
2.36
2.38
1 MHz
2.36
2.38
500 kHz
2.36
2.38
125 kHz
2.36
2.38
Unit
mA
μA
55/115
94
Electrical characteristics
STM32F051xx
I/O system current consumption
The current consumption of the I/O system has two components: static and dynamic.
I/O static current consumption
All the I/Os used as inputs with pull-up generate current consumption when the pin is
externally held low. The value of this current consumption can be simply computed by using
the pull-up/pull-down resistors values given in Table 49: I/O static characteristics.
For the output pins, any external pull-down or external load must also be considered to
estimate the current consumption.
Additional I/O current consumption is due to I/Os configured as inputs if an intermediate
voltage level is externally applied. This current consumption is caused by the input Schmitt
trigger circuits used to discriminate the input value. Unless this specific configuration is
required by the application, this supply current consumption can be avoided by configuring
these I/Os in analog mode. This is notably the case of ADC input pins which should be
configured as analog inputs.
Caution:
Any floating input pin can also settle to an intermediate voltage level or switch inadvertently,
as a result of external electromagnetic noise. To avoid current consumption related to
floating pins, they must either be configured in analog mode, or forced internally to a definite
digital value. This can be done either by using pull-up/down resistors or by configuring the
pins in output mode.
I/O dynamic current consumption
In addition to the internal peripheral current consumption measured previously (see
Table 32: Peripheral current consumption), the I/Os used by an application also contribute
to the current consumption. When an I/O pin switches, it uses the current from the I/O
supply voltage to supply the I/O pin circuitry and to charge/discharge the capacitive load
(internal or external) connected to the pin:
I SW = V DDIOx  f SW  C
where
ISW is the current sunk by a switching I/O to charge/discharge the capacitive load
VDDIOx is the I/O supply voltage
fSW is the I/O switching frequency
C is the total capacitance seen by the I/O pin: C = CINT+ CEXT + CS
CS is the PCB board capacitance including the pad pin.
The test pin is configured in push-pull output mode and is toggled by software at a fixed
frequency.
56/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 31. Switching output I/O current consumption
Symbol
Parameter
Conditions(1)
VDDIOx = 3.3 V
C =CINT
VDDIOx = 3.3 V
CEXT = 0 pF
C = CINT + CEXT+ CS
VDDIOx = 3.3 V
CEXT = 10 pF
C = CINT + CEXT+ CS
ISW
I/O current
consumption
VDDIOx = 3.3 V
CEXT = 22 pF
C = CINT + CEXT+ CS
VDDIOx = 3.3 V
CEXT = 33 pF
C = CINT + CEXT+ CS
VDDIOx = 3.3 V
CEXT = 47 pF
C = CINT + CEXT+ CS
C = Cint
VDDIOx = 2.4 V
CEXT = 47 pF
C = CINT + CEXT+ CS
C = Cint
I/O toggling
frequency (fSW)
Typ
4 MHz
0.07
8 MHz
0.15
16 MHz
0.31
24 MHz
0.53
48 MHz
0.92
4 MHz
0.18
8 MHz
0.37
16 MHz
0.76
24 MHz
1.39
48 MHz
2.188
4 MHz
0.32
8 MHz
0.64
16 MHz
1.25
24 MHz
2.23
48 MHz
4.442
4 MHz
0.49
8 MHz
0.94
16 MHz
2.38
24 MHz
3.99
4 MHz
0.64
8 MHz
1.25
16 MHz
3.24
24 MHz
5.02
4 MHz
0.81
8 MHz
1.7
16 MHz
3.67
4 MHz
0.66
8 MHz
1.43
16 MHz
2.45
24 MHz
4.97
Unit
mA
1. CS = 7 pF (estimated value).
DocID022265 Rev 4
57/115
94
Electrical characteristics
STM32F051xx
On-chip peripheral current consumption
The current consumption of the on-chip peripherals is given in Table 32. The MCU is placed
under the following conditions:

All I/O pins are in input mode with a static value at VDD or VSS (no load)

All peripherals are disabled unless otherwise mentioned

The given value is calculated by measuring the current consumption
–
with all peripherals clocked off
–
with only one peripheral clocked on

Ambient operating temperature and supply voltage conditions summarized in Table 17:
Voltage characteristics

The peripheral clock used is 48 MHz.
58/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 32. Peripheral current consumption
Peripheral
Typical consumption at 25 °C
Unit
IDD
IDDA
ADC(1)
0.53
0.964
CEC
0.24
-
0.10
-
0.27
0.408
DBGMCU
0.18
-
DMA
0.35
-
GPIOA
0.48
-
GPIOB
0.58
-
GPIOC
0.12
-
GPIOD
0.04
-
GPIOF
0.06
-
I2C1
0.43
-
I2C2
0.42
-
PWR
0.22
-
SPI1/I2S1
0.63
-
SPI2
0.53
-
SYSCFG & COMP
0.28
See note (3)
TIM1
1.01
-
TIM2
1.00
-
TIM3
0.78
-
TIM6
0.32
-
TIM14
0.45
-
TIM15
0.66
-
TIM16
0.57
-
TIM17
0.59
-
TSC
0.28
-
USART1
1.07
-
USART2
0.48
-
WWDG
0.22
-
CRC
DAC
(2)
mA
1. ADC is in ready state after setting the ADEN bit in the ADC_CR register (ADRDY bit in ADC_ISR is high).
2. DAC channel 1 enabled by setting EN1 bit in DAC_CR.
3. COMP IDDA is specified as IDD(COMP) in Table 57: Comparator characteristics.
DocID022265 Rev 4
59/115
94
Electrical characteristics
6.3.6
STM32F051xx
Wakeup time from low-power mode
The wakeup times given in Table 33 are the latency between the event and the execution of
the first user instruction. The device goes in low-power mode after the WFE (Wait For
Event) instruction, in the case of a WFI (Wait For Interruption) instruction, 16 CPU cycles
must be added to the following timings due to the interrupt latency in the Cortex M0
architecture.
The SYSCLK clock source setting is kept unchanged after wakeup from Sleep mode. After
wakeup from Stop or Standby mode, SYSCLK takes the default setting: HSI 8 MHz.
The wakeup source from Sleep and Stop mode is an EXTI Line configured in event mode.
The wakeup source from Standby mode is the WKUP1 pin (PA0).
All timings are derived from tests performed under the ambient temperature and supply
voltage conditions summarized in Table 20: General operating conditions except when
explicitly mentioned
Table 33. Low-power mode wakeup timings
Typ @VDD
Symbol
Parameter
Conditions
Max Unit
= 2.0 V = 2.4 V = 2.7 V
tWUSTOP
Wakeup from Stop
mode
Wakeup from
tWUSTANDBY
Standby mode
tWUSLEEP
60/115
=3V
= 3.3 V
Regulator in run
mode
4.20
4.20
4.20
4.20
4.20
5
Regulator in low
power mode
8.05
7.05
6.60
6.27
6.05
9
μs
60.35
55.60
Wakeup from Sleep
mode
53.50
52.02
4 SYSCLK cycles
DocID022265 Rev 4
50.96
-
STM32F051xx
6.3.7
Electrical characteristics
External clock source characteristics
High-speed external user clock generated from an external source
In bypass mode the HSE oscillator is switched off and the input pin is a standard GPIO.
The external clock signal has to respect the I/O characteristics in Section 6.3.14. However,
the recommended clock input waveform is shown in Figure 14: High-speed external clock
source AC timing diagram.
Table 34. High-speed external user clock characteristics
Symbol
Parameter(1)
fHSE_ext
User external clock source frequency
VHSEH
VHSEL
Conditions
Min
Typ
Max
Unit
1
8
32
MHz
OSC_IN input pin high level voltage
0.7 VDD
-
VDD
OSC_IN input pin low level voltage
VSS
-
0.3 VDD
15
-
-
tw(HSEH)
OSC_IN high or low time
tw(HSEL)
tr(HSE)
tf(HSE)
V
ns
OSC_IN rise or fall time
-
-
20
1. Guaranteed by design, not tested in production.
Figure 14. High-speed external clock source AC timing diagram
T7(3%(
6(3%(
6(3%,
TR(3%
TF(3%
T7(3%,
T
4(3%
-36
DocID022265 Rev 4
61/115
94
Electrical characteristics
STM32F051xx
Low-speed external user clock generated from an external source
In bypass mode the LSE oscillator is switched off and the input pin is a standard GPIO.
The external clock signal has to respect the I/O characteristics in Section 6.3.14. However,
the recommended clock input waveform is shown in Figure 15.
Table 35. Low-speed external user clock characteristics
Parameter(1)
Symbol
Conditions
fLSE_ext User external clock source frequency
Min
Typ
Max
Unit
-
32.768
1000
kHz
VLSEH
OSC32_IN input pin high level voltage
0.7 VDD
-
VDD
VLSEL
OSC32_IN input pin low level voltage
VSS
-
0.3 VDD
450
-
-
tw(LSEH)
OSC32_IN high or low time
tw(LSEL)
tr(LSE)
tf(LSE)
V
ns
OSC32_IN rise or fall time
-
-
50
1. Guaranteed by design, not tested in production.
Figure 15. Low-speed external clock source AC timing diagram
T7,3%(
6,3%(
6,3%,
TR,3%
TF,3%
T7,3%,
T
4,3%
-36
62/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
High-speed external clock generated from a crystal/ceramic resonator
The high-speed external (HSE) clock can be supplied with a 4 to 32 MHz crystal/ceramic
resonator oscillator. All the information given in this paragraph are based on design
simulation results obtained with typical external components specified in Table 36. In the
application, the resonator and the load capacitors have to be placed as close as possible to
the oscillator pins in order to minimize output distortion and startup stabilization time. Refer
to the crystal resonator manufacturer for more details on the resonator characteristics
(frequency, package, accuracy).
Table 36. HSE oscillator characteristics
Symbol
fOSC_IN
Parameter
Conditions(1)
Min(2)
Typ
Max(2)
Unit
4
8
32
MHz
-
200
-
k
Oscillator frequency
Feedback resistor
RF
(3)
During startup
IDD
HSE current consumption
gm
tSU(HSE)
Oscillator transconductance
(4)
Startup time
-
8.5
VDD = 3.3 V,
Rm = 30 ,
CL = 10 [email protected] MHz
-
0.4
-
VDD = 3.3 V,
Rm = 45 ,
CL = 10 [email protected] MHz
-
0.5
-
VDD = 3.3 V,
Rm = 30 ,
CL = 5 [email protected] MHz
-
0.8
-
VDD = 3.3 V,
Rm = 30 ,
CL = 10 [email protected] MHz
-
1
-
VDD = 3.3 V,
Rm = 30 ,
CL = 20 [email protected] MHz
-
1.5
-
Startup
10
-
-
mA/V
VDD is stabilized
-
2
-
ms
mA
1. Resonator characteristics given by the crystal/ceramic resonator manufacturer.
2. Guaranteed by design, not tested in production.
3. This consumption level occurs during the first 2/3 of the tSU(HSE) startup time
4. tSU(HSE) is the startup time measured from the moment it is enabled (by software) to a stabilized 8 MHz
oscillation is reached. This value is measured for a standard crystal resonator and it can vary significantly
with the crystal manufacturer
For CL1 and CL2, it is recommended to use high-quality external ceramic capacitors in the
5 pF to 20 pF range (typ.), designed for high-frequency applications, and selected to match
the requirements of the crystal or resonator (see Figure 16). CL1 and CL2 are usually the
same size. The crystal manufacturer typically specifies a load capacitance which is the
series combination of CL1 and CL2. PCB and MCU pin capacitance must be included (10 pF
can be used as a rough estimate of the combined pin and board capacitance) when sizing
CL1 and CL2.
Note:
For information on selecting the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available from the ST website www.st.com.
DocID022265 Rev 4
63/115
94
Electrical characteristics
STM32F051xx
Figure 16. Typical application with an 8 MHz crystal
2ESONATORWITH
INTEGRATEDCAPACITORS
#,
F(3%
/3#?).
-( Z
RESONATOR
#,
2%84
2&
"IAS
CONTROLLED
GAIN
/3#?/5 4
-36
1. REXT value depends on the crystal characteristics.
64/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Low-speed external clock generated from a crystal resonator
The low-speed external (LSE) clock can be supplied with a 32.768 kHz crystal resonator
oscillator. All the information given in this paragraph are based on design simulation results
obtained with typical external components specified in Table 37. In the application, the
resonator and the load capacitors have to be placed as close as possible to the oscillator
pins in order to minimize output distortion and startup stabilization time. Refer to the crystal
resonator manufacturer for more details on the resonator characteristics (frequency,
package, accuracy).
Table 37. LSE oscillator characteristics (fLSE = 32.768 kHz)
Symbol
IDD
gm
Parameter
LSE current consumption
Oscillator
transconductance
tSU(LSE)(3) Startup time
Conditions(1)
Min(2)
Typ
Max(2) Unit
LSEDRV[1:0]=00
lower driving capability
-
0.5
0.9
LSEDRV[1:0]= 01
medium low driving capability
-
-
1
LSEDRV[1:0] = 10
medium high driving capability
-
-
1.3
LSEDRV[1:0]=11
higher driving capability
-
-
1.6
LSEDRV[1:0]=00
lower driving capability
5
-
-
LSEDRV[1:0]= 01
medium low driving capability
8
-
-
LSEDRV[1:0] = 10
medium high driving capability
15
-
-
LSEDRV[1:0]=11
higher driving capability
25
-
-
VDD is stabilized
-
2
-
μA
μA/V
s
1. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator design guide for
ST microcontrollers”.
2. Guaranteed by design, not tested in production.
3.
tSU(LSE) is the startup time measured from the moment it is enabled (by software) to a stabilized 32.768 kHz oscillation is
reached. This value is measured for a standard crystal and it can vary significantly with the crystal manufacturer
Note:
For information on selecting the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available from the ST website www.st.com.
DocID022265 Rev 4
65/115
94
Electrical characteristics
STM32F051xx
Figure 17. Typical application with a 32.768 kHz crystal
2ESONATORWITH
INTEGRATEDCAPACITORS
#,
F,3%
/3#?).
$RIVE
PROGRAMMABLE
AMPLIFIER
K( Z
RESONATOR
#,
/3#?/5 4
-36
Note:
66/115
An external resistor is not required between OSC32_IN and OSC32_OUT and it is forbidden
to add one.
DocID022265 Rev 4
STM32F051xx
6.3.8
Electrical characteristics
Internal clock source characteristics
The parameters given in Table 38 are derived from tests performed under ambient
temperature and supply voltage conditions summarized in Table 20: General operating
conditions. The provided curves are characterization results, not tested in production.
High-speed internal (HSI) RC oscillator
Table 38. HSI oscillator characteristics(1)
Symbol
fHSI
TRIM
DuCy(HSI)
ACCHSI
Parameter
Conditions
Min
Typ
Max
Unit
Frequency
-
8
-
MHz
HSI user trimming step
-
-
1(2)
%
Duty cycle
(2)
45
Accuracy of the HSI
oscillator (factory
calibrated)
-
55
(2)
%
%
TA = –40 to 105 °C
–3.8(3)
-
4.6(3)
TA = –10 to 85 °C
–2.9(3)
-
2.9(3)
%
TA = 0 to 70 °C
–1.3(3)
-
2.2(3)
%
–1
-
1
%
TA = 25 °C
tsu(HSI)
HSI oscillator startup
time
1(2)
-
2(2)
μs
IDDA(HSI)
HSI oscillator power
consumption
-
80
100(2)
μA
1. VDDA = 3.3 V, TA = –40 to 105 °C unless otherwise specified.
2. Guaranteed by design, not tested in production.
3. Data based on characterization results, not tested in production.
Figure 18. HSI oscillator accuracy characterization results
-!8
-).
4; #=
!
-36
DocID022265 Rev 4
67/115
94
Electrical characteristics
STM32F051xx
High-speed internal 14 MHz (HSI14) RC oscillator (dedicated to ADC)
Table 39. HSI14 oscillator characteristics(1)
Symbol
fHSI14
TRIM
Parameter
Conditions
Min
Typ
-
14
Frequency
HSI14 user-trimming step
-
DuCy(HSI14) Duty cycle
45
Accuracy of the HSI14
oscillator (factory calibrated)
TA = –10 to 85 °C
TA = 25 °C
tsu(HSI14)
IDDA(HSI14)
HSI14 oscillator startup time
MHz
-
1
55
%
(2)
%
(3)
-
5.1
%
–3.2(3)
-
3.1(3)
%
–1.3
-
(3)
2.2
%
–1
-
1
%
-
(2)
μs
1
HSI14 oscillator power
consumption
(2)
(3)
(3)
TA = 0 to 70 °C
Unit
-
(2)
TA = –40 to 105 °C –4.2
ACCHSI14
Max
(2)
-
100
2
150(2)
μA
1. VDDA = 3.3 V, TA = –40 to 105 °C unless otherwise specified.
2. Guaranteed by design, not tested in production.
3. Data based on characterization results, not tested in production.
Figure 19. HSI14 oscillator accuracy characterization results
-!8
-).
4; #=
!
-36
68/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Low-speed internal (LSI) RC oscillator
Table 40. LSI oscillator characteristics(1)
Symbol
fLSI
tsu(LSI)
Parameter
Min
Typ
Max
Unit
30
40
50
kHz
LSI oscillator startup time
-
-
85
μs
LSI oscillator power consumption
-
0.75
1.2
μA
Frequency
(2)
IDDA(LSI)(2)
1. VDDA = 3.3 V, TA = –40 to 105 °C unless otherwise specified.
2. Guaranteed by design, not tested in production.
6.3.9
PLL characteristics
The parameters given in Table 41 are derived from tests performed under ambient
temperature and supply voltage conditions summarized in Table 20: General operating
conditions.
Table 41. PLL characteristics
Value
Symbol
fPLL_IN
fPLL_OUT
tLOCK
JitterPLL
Parameter
Unit
Min
Typ
Max
1(2)
8.0
24(2)
MHz
PLL input clock duty cycle
40
(2)
-
60(2)
%
PLL multiplier output clock
16(2)
-
48
MHz
PLL lock time
-
-
200(2)
μs
Cycle-to-cycle jitter
-
-
300(2)
ps
PLL input clock(1)
1. Take care to use the appropriate multiplier factors to obtain PLL input clock values compatible with the
range defined by fPLL_OUT.
2. Guaranteed by design, not tested in production.
DocID022265 Rev 4
69/115
94
Electrical characteristics
6.3.10
STM32F051xx
Memory characteristics
Flash memory
The characteristics are given at TA = –40 to 105 °C unless otherwise specified.
Table 42. Flash memory characteristics
Min
Typ
Max(1)
Unit
16-bit programming time TA–40 to +105 °C
40
53.5
60
μs
Page (1 KB) erase time
TA –40 to +105 °C
20
-
40
ms
tME
Mass erase time
TA –40 to +105 °C
20
-
40
ms
IDD
Supply current
Write mode
-
-
10
mA
Erase mode
-
-
12
mA
2
-
3.6
V
Symbol
tprog
tERASE
Vprog
Parameter
Conditions
Programming voltage
1. Guaranteed by design, not tested in production.
Table 43. Flash memory endurance and data retention
Symbol
NEND
tRET
Min(1)
Unit
TA = –40 to +105 °C
10
kcycles
1 kcycle(2) at TA = 85 °C
30
Parameter
Endurance
Data retention
Conditions
1 kcycle
(2)
at TA = 105 °C
10
(2)
20
10 kcycles
at TA = 55 °C
Years
1. Data based on characterization results, not tested in production.
2. Cycling performed over the whole temperature range.
6.3.11
EMC characteristics
Susceptibility tests are performed on a sample basis during device characterization.
Functional EMS (electromagnetic susceptibility)
While a simple application is executed on the device (toggling 2 LEDs through I/O ports).
the device is stressed by two electromagnetic events until a failure occurs. The failure is
indicated by the LEDs:

Electrostatic discharge (ESD) (positive and negative) is applied to all device pins until
a functional disturbance occurs. This test is compliant with the IEC 61000-4-2 standard.

FTB: A Burst of Fast Transient voltage (positive and negative) is applied to VDD and
VSS through a 100 pF capacitor, until a functional disturbance occurs. This test is
compliant with the IEC 61000-4-4 standard.
A device reset allows normal operations to be resumed.
The test results are given in Table 44. They are based on the EMS levels and classes
defined in application note AN1709.
70/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 44. EMS characteristics
Symbol
Parameter
Level/
Class
Conditions
VFESD
VDD 3.3 V, LQFP64, TA +25 °C,
Voltage limits to be applied on any I/O pin to
fHCLK 48 MHz,
induce a functional disturbance
conforming to IEC 61000-4-2
2B
VEFTB
Fast transient voltage burst limits to be
applied through 100 pF on VDD and VSS
pins to induce a functional disturbance
VDD3.3 V, LQFP64, TA +25 °C,
fHCLK 48 MHz,
conforming to IEC 61000-4-4
3B
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software. It should be noted that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for his application.
Software recommendations
The software flowchart must include the management of runaway conditions such as:

Corrupted program counter

Unexpected reset

Critical Data corruption (control registers...)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the NRST pin or the Oscillator pins for 1
second.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behavior is detected, the software can be hardened
to prevent unrecoverable errors occurring (see application note AN1015).
Electromagnetic Interference (EMI)
The electromagnetic field emitted by the device are monitored while a simple application is
executed (toggling 2 LEDs through the I/O ports). This emission test is compliant with
IEC 61967-2 standard which specifies the test board and the pin loading.
Table 45. EMI characteristics
Symbol Parameter
SEMI
Conditions
Monitored
frequency band
0.1 to 30 MHz
VDD 3.6 V, TA 25 °C,
30 to 130 MHz
LQFP64 package
Peak level
compliant with IEC
130 MHz to 1GHz
61967-2
SAE EMI Level
DocID022265 Rev 4
Max vs. [fHSE/fHCLK]
Unit
8/48 MHz
-3
28
dBμV
23
4
-
71/115
94
Electrical characteristics
6.3.12
STM32F051xx
Electrical sensitivity characteristics
Based on three different tests (ESD, LU) using specific measurement methods, the device is
stressed in order to determine its performance in terms of electrical sensitivity.
Electrostatic discharge (ESD)
Electrostatic discharges (a positive then a negative pulse separated by 1 second) are
applied to the pins of each sample according to each pin combination. The sample size
depends on the number of supply pins in the device (3 parts × (n+1) supply pins). This test
conforms to the JESD22-A114/C101 standard.
Table 46. ESD absolute maximum ratings
Symbol
VESD(HBM)
Ratings
Conditions
Electrostatic discharge
TA +25 °C, conforming
voltage (human body model) to JESD22-A114
Electrostatic discharge
VESD(CDM) voltage (charge device
model)
TA +25 °C, conforming
to ANSI/ESD STM5.3.1
Class
Maximum
value(1)
2
2000
Unit
V
II
500
1. Data based on characterization results, not tested in production.
Static latch-up
Two complementary static tests are required on six parts to assess the latch-up
performance:

A supply overvoltage is applied to each power supply pin.

A current injection is applied to each input, output and configurable I/O pin.
These tests are compliant with EIA/JESD 78A IC latch-up standard.
Table 47. Electrical sensitivities
Symbol
LU
6.3.13
Parameter
Static latch-up class
Conditions
TA +105 °C conforming to JESD78A
Class
II level A
I/O current injection characteristics
As a general rule, current injection to the I/O pins, due to external voltage below VSS or
above VDDIOx (for standard, 3.3 V-capable I/O pins) should be avoided during normal
product operation. However, in order to give an indication of the robustness of the
microcontroller in cases when abnormal injection accidentally happens, susceptibility tests
are performed on a sample basis during device characterization.
72/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Functional susceptibility to I/O current injection
While a simple application is executed on the device, the device is stressed by injecting
current into the I/O pins programmed in floating input mode. While current is injected into
the I/O pin, one at a time, the device is checked for functional failures.
The failure is indicated by an out of range parameter: ADC error above a certain limit (higher
than 5 LSB TUE), out of conventional limits of induced leakage current on adjacent pins (out
of the -5 μA/+0 μA range) or other functional failure (for example reset occurrence or
oscillator frequency deviation).
The characterization results are given in Table 48.
Negative induced leakage current is caused by negative injection and positive induced
leakage current is caused by positive injection.
Table 48. I/O current injection susceptibility
Functional
susceptibility
Symbol
IINJ
6.3.14
Description
Unit
Negative
injection
Positive
injection
Injected current on BOOT0
–0
NA
Injected current on PA10, PA12, PB4, PB5, PB10, PB15
and PD2 pins with induced leakage current on adjacent
pins less than –10 μA
–5
NA
Injected current on all other FT and FTf pins
–5
NA
Injected current on PA6 and PC0
–0
+5
Injected current on all other TTa, TC and RST pins
–5
+5
mA
I/O port characteristics
General input/output characteristics
Unless otherwise specified, the parameters given in Table 49 are derived from tests
performed under the conditions summarized in Table 20: General operating conditions. All
I/Os are designed as CMOS- and TTL-compliant (except BOOT0).
Table 49. I/O static characteristics
Symbol
VIL
Parameter
Low level input
voltage
Conditions
Min
Typ
Max
TC and TTa I/O
-
-
0.3 VDDIOx+0.07(1)
FT and FTf I/O
-
-
0.475 VDDIOx–0.2(1)
BOOT0
-
-
0.3 VDDIOx–0.3(1)
All I/Os except
BOOT0 pin
-
-
0.3 VDDIOx
DocID022265 Rev 4
Unit
V
73/115
94
Electrical characteristics
STM32F051xx
Table 49. I/O static characteristics (continued)
Symbol
VIH
Vhys
Ilkg
RPU
Parameter
High level input
voltage
Schmitt trigger
hysteresis
Input leakage
current(2)
Weak pull-up
equivalent resistor
(4)
RPD
Weak pull-down
equivalent
resistor(4)
CIO
I/O pin capacitance
Conditions
Min
TC and TTa I/O
0.445 VDDIOx+0.398
FT and FTf I/O
0.5 VDDIOx+0.2(1)
(1)
(1)
0.2 VDDIOx+0.95
BOOT0
Typ
Max
-
-
-
-
-
-
V
All I/Os except
BOOT0 pin
0.7 VDDIOx
-
TC and TTa I/O
-
200(1)
-
FT and FTf I/O
-
(1)
100
-
BOOT0
-
300(1)
-
TC, FT and FTf I/O
TTa in digital mode
VSS  VIN VDDIOx
-
-
0.1
TTa in digital mode
VDDIOx  VIN VDDA
-
-
1
TTa in analog mode
VSS  VIN VDDA
-
-
0.2
FT and FTf I/O (3)
VDDIOx VIN 5 V
-
-
10
VIN VSS
25
40
55
k
VIN VDDIOx
25
40
55
k
-
5
-
pF
1. Data based on design simulation only. Not tested in production.
2. The leakage could be higher than the maximum value, if negative current is injected on adjacent pins. Refer to Table 48:
I/O current injection susceptibility.
3. To sustain a voltage higher than VDDIOx +0.3 V, the internal pull-up/pull-down resistors must be disabled.
4. Pull-up and pull-down resistors are designed with a true resistance in series with a switchable PMOS/NMOS. This
PMOS/NMOS contribution to the series resistance is minimal (~10% order).
74/115
Unit
DocID022265 Rev 4
mV
μA
STM32F051xx
Electrical characteristics
All I/Os are CMOS- and TTL-compliant (no software configuration required). Their
characteristics cover more than the strict CMOS-technology or TTL parameters. The
coverage of these requirements is shown in Figure 20 for standard I/Os, and in Figure 21 for
5 V tolerant I/Os.
Figure 20. TC and TTa I/O input characteristics
99
,1
,2[
9 '
'
9 ,+PLQ
7HVWHGUDQJH
QWV
77/VWDQGDUGUHTXLUHPHQW
LUHPH
UHTX
GDUG
VWDQ
6
&02
9 ,+PLQ
[
9 '',2
8QGHILQHGLQSXWUDQJH
9 ,2[
9,/PD[ ''
9 ,2[
9,/PD[ ''
LUHPHQWV
QGDUGUHTX
&026VWD
77/VWDQGDUGUHTXLUHPHQW
7HVWHGUDQJH
99
'',2[
069
Figure 21. Five volt tolerant (FT and FTf) I/O input characteristics
99
,1
[
9 ',2
'
9 ,+PLQ
7HVWHGUDQJH
77/VWDQGDUGUHTXLUHPHQW
WV
HPHQ
UHTXLU
DUG
VWDQG
6
&02
8QGHILQHGLQSXWUDQJH
9 '',2[
9 ,+PLQ
[
9 '',2
[
9 ,/PD
9 ,2[
9,/PD[ ''
77/VWDQGDUGUHTXLUHPHQW
HQWV
UGUHTXLUHP
QGD
&026VWD
7HVWHGUDQJH
99
'',2[
069
DocID022265 Rev 4
75/115
94
Electrical characteristics
STM32F051xx
Output driving current
The GPIOs (general purpose input/outputs) can sink or source up to +/-8 mA, and sink or
source up to +/- 20 mA (with a relaxed VOL/VOH).
In the user application, the number of I/O pins which can drive current must be limited to
respect the absolute maximum rating specified in Section 6.2:

The sum of the currents sourced by all the I/Os on VDDIOx, plus the maximum
consumption of the MCU sourced on VDD, cannot exceed the absolute maximum rating
IVDD (see Table 18: Current characteristics).

The sum of the currents sunk by all the I/Os on VSS, plus the maximum consumption of
the MCU sunk on VSS, cannot exceed the absolute maximum rating IVSS (see
Table 18: Current characteristics).
Output voltage levels
Unless otherwise specified, the parameters given in the table below are derived from tests
performed under the ambient temperature and supply voltage conditions summarized in
Table 20: General operating conditions. All I/Os are CMOS- and TTL-compliant (FT, TTa or
TC unless otherwise specified).
Table 50. Output voltage characteristics(1)
Symbol
Parameter
VOL
Output low level voltage for an I/O pin
VOH
Output high level voltage for an I/O pin
VOL
Output low level voltage for an I/O pin
VOH
Output high level voltage for an I/O pin
VOL(3)
Output low level voltage for an I/O pin
VOH(3)
Output high level voltage for an I/O pin
VOL(3)
Output low level voltage for an I/O pin
VOH(3)
Output high level voltage for an I/O pin
VOLFM+
(4)
Output low level voltage for an FTf I/O pin in
FM+ mode
Conditions
Min
Max
CMOS port(2)
|IIO| = 8 mA
VDDIOx  2.7 V
-
0.4
VDDIOx–0.4
-
-
0.4
2.4
-
-
1.3
VDDIOx–1.3
-
-
0.4
VDDIOx–0.4
-
|IIO| = 20 mA
VDDIOx  2.7 V
-
0.4
V
|IIO| = 10 mA
-
0.4
V
TTL port(2)
|IIO| = 8 mA
VDDIOx  2.7 V
|IIO| = 20 mA
VDDIOx  2.7 V
|IIO| = 6 mA
Unit
V
V
V
V
1. The IIO current sourced or sunk by the device must always respect the absolute maximum rating specified in Table 18:
Current characteristics, and the sum of the currents sourced or sunk by all the I/Os (I/O ports and control pins) must always
respect the absolute maximum ratings IIO.
2. TTL and CMOS outputs are compatible with JEDEC standards JESD36 and JESD52.
3. Data based on characterization results. Not tested in production.
4. Data based on design simulation only. Not tested in production.
76/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Input/output AC characteristics
The definition and values of input/output AC characteristics are given in Figure 22 and
Table 51, respectively.
Unless otherwise specified, the parameters given are derived from tests performed under
the ambient temperature and supply voltage conditions summarized in Table 20: General
operating conditions.
Table 51. I/O AC characteristics(1)(2)
OSPEEDRy
[1:0]
value(1)
Symbol
Parameter
Conditions
Min
Max
Unit
-
2
MHz
-
125
-
125
-
10
-
25
-
25
CL = 30 pF, VDDIOx  2.7 V
-
50
CL = 50 pF, VDDIOx  2.7 V
-
30
CL = 50 pF, VDDIOx  2.7 V
-
20
CL = 30 pF, VDDIOx  2.7 V
-
5
CL = 50 pF, VDDIOx  2.7 V
-
8
CL = 50 pF, VDDIOx  2.7 V
-
12
CL = 30 pF, VDDIOx  2.7 V
-
5
CL = 50 pF, VDDIOx  2.7 V
-
8
CL = 50 pF, VDDIOx  2.7 V
-
12
-
2
-
12
-
34
10
-
fmax(IO)out Maximum frequency(3)
x0
tf(IO)out
Output fall time
tr(IO)out
Output rise time
CL = 50 pF
fmax(IO)out Maximum frequency(3)
01
tf(IO)out
Output fall time
tr(IO)out
Output rise time
fmax(IO)out Maximum
11
tf(IO)out
tr(IO)out
FM+
configuration
(4)
frequency(3)
Output fall time
Output rise time
fmax(IO)out Maximum
CL = 50 pF
frequency(3)
tf(IO)out
Output fall time
tr(IO)out
Output rise time
tEXTIpw
Pulse width of external
signals detected by
the EXTI controller
CL = 50 pF
ns
MHz
ns
MHz
ns
MHz
ns
ns
1. The I/O speed is configured using the OSPEEDRx[1:0] bits. Refer to the STM32F0xxxx RM0091 reference
manual for a description of GPIO Port configuration register.
2. Guaranteed by design, not tested in production.
3. The maximum frequency is defined in Figure 22.
4. When FM+ configuration is set, the I/O speed control is bypassed. Refer to the STM32F0xxxx reference
manual RM0091 for a detailed description of FM+ I/O configuration.
DocID022265 Rev 4
77/115
94
Electrical characteristics
STM32F051xx
Figure 22. I/O AC characteristics definition
W I,2RXW
W U,2RXW
7
0D[LPXPIUHTXHQF\LVDFKLHYHGLIWW”7DQGLIWKHGXW\F\FOHLV
U I
ZKHQORDGHGE\WKHVSHFLILHGFDSDFLWDQFH
069
6.3.15
NRST pin characteristics
The NRST pin input driver uses the CMOS technology. It is connected to a permanent pullup resistor, RPU.
Unless otherwise specified, the parameters given in the table below are derived from tests
performed under the ambient temperature and supply voltage conditions summarized in
Table 20: General operating conditions.
Table 52. NRST pin characteristics
Symbol
Parameter
VIL(NRST)
Min
Typ
Max
NRST input low level voltage
-
-
0.3 VDD+0.07(1)
VIH(NRST)
NRST input high level voltage
0.445 VDD+0.398(1)
-
-
Vhys(NRST)
NRST Schmitt trigger voltage
hysteresis
-
200
-
mV
25
40
55
k
-
-
100(1)
ns
2.7 < VDD < 3.6
300(1)
-
-
2.0 < VDD < 3.6
500(1)
-
-
RPU
Weak pull-up equivalent
resistor(2)
VF(NRST)
NRST input filtered pulse
VNF(NRST) NRST input not filtered pulse
Conditions
VIN VSS
1. Data based on design simulation only. Not tested in production.
2. The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution to the series
resistance is minimal (~10% order).
78/115
DocID022265 Rev 4
Unit
V
ns
STM32F051xx
Electrical characteristics
Figure 23. Recommended NRST pin protection
([WHUQDO
UHVHWFLUFXLW 9 ''
5 38
1567 ,QWHUQDOUHVHW
)LOWHU
—)
069
1. The external capacitor protects the device against parasitic resets.
2. The user must ensure that the level on the NRST pin can go below the VIL(NRST) max level specified in
Table 52: NRST pin characteristics. Otherwise the reset will not be taken into account by the device.
6.3.16
12-bit ADC characteristics
Unless otherwise specified, the parameters given in Table 53 are preliminary values derived
from tests performed under ambient temperature, fPCLK frequency and VDDA supply voltage
conditions summarized in Table 20: General operating conditions.
Note:
It is recommended to perform a calibration after each power-up.
Table 53. ADC characteristics
Symbol
Parameter
VDDA
Analog supply voltage for
ADC ON
IDDA (ADC)
Current consumption of
the ADC(1)
Conditions
VDD = VDDA = 3.3 V
Min
Typ
Max
Unit
2.4
-
3.6
V
-
0.9
-
mA
fADC
ADC clock frequency
0.6
-
14
MHz
fS(2)
Sampling rate
0.05
-
1
MHz
-
-
823
kHz
-
-
17
1/fADC
0
-
VDDA
V
-
-
50
k
fADC = 14 MHz
fTRIG(2)
External trigger frequency
VAIN
Conversion voltage range
RAIN(2)
External input impedance
RADC(2)
Sampling switch
resistance
-
-
1
k
CADC(2)
Internal sample and hold
capacitor
-
-
8
pF
tCAL(2)
Calibration time
See Equation 1 and
Table 54 for details
fADC = 14 MHz
DocID022265 Rev 4
5.9
μs
83
1/fADC
79/115
94
Electrical characteristics
STM32F051xx
Table 53. ADC characteristics (continued)
Symbol
Parameter
Conditions
Min
Typ
Max
1.5 ADC
cycles + 2
fPCLK cycles
-
1.5 ADC
cycles + 3
fPCLK cycles
ADC clock = PCLK/2
-
4.5
-
fPCLK
cycle
ADC clock = PCLK/4
-
8.5
-
fPCLK
cycle
ADC clock = HSI14
WLATENCY(2)
tlatr(2)
ADC_DR register write
latency
fADC = fPCLK/2 = 14 MHz
0.196
μs
fADC = fPCLK/2
5.5
1/fPCLK
0.219
μs
10.5
1/fPCLK
Trigger conversion latency fADC = fPCLK/4 = 12 MHz
fADC = fPCLK/4
JitterADC
fADC = fHSI14 = 14 MHz
0.188
-
0.259
μs
fADC = fHSI14
-
1
-
1/fHSI14
fADC = 14 MHz
0.107
-
17.1
μs
1.5
-
239.5
1/fADC
0
0
1
μs
1
-
18
μs
ADC jitter on trigger
conversion
tS(2)
Sampling time
tSTAB(2)
Power-up time
tCONV(2)
Total conversion time
(including sampling time)
Unit
fADC = 14 MHz
14 to 252 (tS for sampling +12.5 for
successive approximation)
1/fADC
1. During conversion of the sampled value (12.5 x ADC clock period), an additional consumption of 100 μA on IDDA and 60 μA
on IDD should be taken into account.
2. Guaranteed by design, not tested in production.
Equation 1: RAIN max formula
TS
R AIN  ------------------------------------------------------------- – R ADC
N+2
f ADC  C ADC  ln  2

The formula above (Equation 1) is used to determine the maximum external impedance
allowed for an error below 1/4 of LSB. Here N = 12 (from 12-bit resolution).
Table 54. RAIN max for fADC = 14 MHz
80/115
Ts (cycles)
tS (μs)
RAIN max (k)(1)
1.5
0.11
0.4
7.5
0.54
5.9
13.5
0.96
11.4
28.5
2.04
25.2
41.5
2.96
37.2
55.5
3.96
50
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 54. RAIN max for fADC = 14 MHz (continued)
Ts (cycles)
tS (μs)
RAIN max (k)(1)
71.5
5.11
NA
239.5
17.1
NA
1. Guaranteed by design, not tested in production.
Table 55. ADC accuracy(1)(2)(3)
Symbol
Parameter
Test conditions
Typ
Max(4)
±1.3
±2
±1
±1.5
±0.5
±1.5
±0.7
±1
ET
Total unadjusted error
EO
Offset error
EG
Gain error
ED
Differential linearity error
EL
Integral linearity error
±0.8
±1.5
ET
Total unadjusted error
±3.3
±4
EO
Offset error
±1.9
±2.8
EG
Gain error
±2.8
±3
ED
Differential linearity error
±0.7
±1.3
EL
Integral linearity error
±1.2
±1.7
ET
Total unadjusted error
±3.3
±4
EO
Offset error
±1.9
±2.8
EG
Gain error
±2.8
±3
ED
Differential linearity error
±0.7
±1.3
EL
Integral linearity error
±1.2
±1.7
fPCLK = 48 MHz,
fADC = 14 MHz, RAIN < 10 k
VDDA = 3 V to 3.6 V
TA = 25 °C
fPCLK = 48 MHz,
fADC = 14 MHz, RAIN < 10 k
VDDA = 2.7 V to 3.6 V
TA = 40 to 105 °C
fPCLK = 48 MHz,
fADC = 14 MHz, RAIN < 10 k
VDDA = 2.4 V to 3.6 V
TA = 25 °C
Unit
LSB
LSB
LSB
1. ADC DC accuracy values are measured after internal calibration.
2. ADC Accuracy vs. Negative Injection Current: Injecting negative current on any of the standard (nonrobust) analog input pins should be avoided as this significantly reduces the accuracy of the conversion
being performed on another analog input. It is recommended to add a Schottky diode (pin to ground) to
standard analog pins which may potentially inject negative current.
Any positive injection current within the limits specified for IINJ(PIN) and IINJ(PIN) in Section 6.3.14 does not
affect the ADC accuracy.
3. Better performance may be achieved in restricted VDDA, frequency and temperature ranges.
4. Data based on characterization results, not tested in production.
DocID022265 Rev 4
81/115
94
Electrical characteristics
STM32F051xx
Figure 24. ADC accuracy characteristics
%'
%XAMPLEOFANACTUALTRANSFERCURVE
4HEIDEALTRANSFERCURVE
%NDPOINTCORRELATIONLINE
%4
%44OTAL 5NADJUSTED %RROR MAXIMUM DEVIATION
BETWEENTHEACTUALANDTHEIDEALTRANSFERCURVES
%//FFSET%RRORDEVIATIONBETWEENTHEFIRSTACTUAL
TRANSITIONANDTHEFIRSTIDEALONE
%''AIN %RROR DEVIATION BETWEEN THE LAST IDEAL
TRANSITIONANDTHELASTACTUALONE
%$$IFFERENTIAL,INEARITY%RRORMAXIMUMDEVIATION
BETWEENACTUALSTEPSANDTHEIDEALONE
%,)NTEGRAL ,INEARITY %RROR MAXIMUM DEVIATION
BETWEEN ANY ACTUAL TRANSITION AND THE END POINT
CORRELATIONLINE
%/
%,
%$
,3")$%!,
633!
6$$!
-36
Figure 25. Typical connection diagram using the ADC
9 ''$
6DPSOHDQGKROG$'&
FRQ YHU WHU
97
5 $,1 9$,1
5 $'&
$,1[
& SDU DVLWLF
97
,/ “ —$
ELW
FRQ YHU WHU
&$'&
069
1. Refer to Table 53: ADC characteristics for the values of RAIN, RADC and CADC.
2. Cparasitic represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
pad capacitance (roughly 7 pF). A high Cparasitic value will downgrade conversion accuracy. To remedy
this, fADC should be reduced.
General PCB design guidelines
Power supply decoupling should be performed as shown in Figure 12: Power supply
scheme. The 10 nF capacitor should be ceramic (good quality) and it should be placed as
close as possible to the chip.
82/115
DocID022265 Rev 4
STM32F051xx
6.3.17
Electrical characteristics
DAC electrical specifications
Table 56. DAC characteristics
Symbol
Parameter
Min
Typ
Max
Unit
Comments
VDDA
Analog supply voltage for
DAC ON
2.4
-
3.6
V
RLOAD(1)
Resistive load with buffer
ON
5
-
-
k
Load is referred to ground
RO(1)
CLOAD(1)
Impedance output with
buffer OFF
-
-
15
k
When the buffer is OFF, the
Minimum resistive load between
DAC_OUT and VSS to have a
1% accuracy is 1.5 M
Capacitive load
-
-
50
pF
Maximum capacitive load at
DAC_OUT pin (when the buffer
is ON).
It gives the maximum output
excursion of the DAC.
It corresponds to 12-bit input
code (0x0E0) to (0xF1C) at
VDDA = 3.6 V and (0x155) and
(0xEAB) at VDDA = 2.4 V
DAC_OUT
min(1)
Lower DAC_OUT voltage
with buffer ON
0.2
-
-
V
DAC_OUT
max(1)
Higher DAC_OUT voltage
with buffer ON
-
-
VDDA – 0.2
V
DAC_OUT
min(1)
Lower DAC_OUT voltage
with buffer OFF
-
0.5
-
mV
DAC_OUT
max(1)
Higher DAC_OUT voltage
with buffer OFF
-
-
VDDA – 1LSB
V
-
-
380
μA
IDDA(1)
DAC DC current
consumption in quiescent
mode(2)
With no load, middle code
(0x800) on the input
-
-
480
μA
With no load, worst code
(0xF1C) on the input
Differential non linearity
Difference between two
consecutive code-1LSB)
-
-
±0.5
LSB
Given for the DAC in 10-bit
configuration
-
-
±2
LSB
Given for the DAC in 12-bit
configuration
-
-
±1
LSB
Given for the DAC in 10-bit
configuration
-
-
±4
LSB
Given for the DAC in 12-bit
configuration
-
-
±10
mV
-
-
±3
LSB
Given for the DAC in 10-bit at
VDDA = 3.6 V
-
-
±12
LSB
Given for the DAC in 12-bit at
VDDA = 3.6 V
-
-
±0.5
%
DNL(3)
INL(3)
Offset(3)
Integral non linearity
(difference between
measured value at Code i
and the value at Code i on a
line drawn between Code 0
and last Code 1023)
Offset error
(difference between
measured value at Code
(0x800) and the ideal value
= VDDA/2)
Gain error(3) Gain error
DocID022265 Rev 4
It gives the maximum output
excursion of the DAC.
Given for the DAC in 12-bit
configuration
83/115
94
Electrical characteristics
STM32F051xx
Table 56. DAC characteristics (continued)
Symbol
Min
Typ
Max
Unit
Settling time (full scale: for a
10-bit input code transition
(3) between the lowest and the
tSETTLING
highest input codes when
DAC_OUT reaches final
value ±1LSB
-
3
4
μs
Max frequency for a correct
DAC_OUT change when
small variation in the input
code (from code i to i+1LSB)
-
-
1
tWAKEUP(3)
Wakeup time from off state
(Setting the ENx bit in the
DAC Control register)
-
6.5
10
μs
CLOAD  50 pF, RLOAD  5 k
input code between lowest and
highest possible ones.
PSRR+ (1)
Power supply rejection ratio
(to VDDA) (static DC
measurement
-
–67
–40
dB
No RLOAD, CLOAD = 50 pF
Update
rate(3)
Parameter
Comments
CLOAD  50 pF, RLOAD  5 k
MS/s CLOAD  50 pF, RLOAD  5 k
1. Guaranteed by design, not tested in production.
2. The DAC is in “quiescent mode” when it keeps the value steady on the output so no dynamic consumption is involved.
3. Data based on characterization results, not tested in production.
Figure 26. 12-bit buffered / non-buffered DAC
Buffered/Non-buffered DAC
Buffer(1)
R LOAD
12-bit
digital to
analog
converter
DACx_OUT
C LOAD
ai17157
1. The DAC integrates an output buffer that can be used to reduce the output impedance and to drive external loads directly
without the use of an external operational amplifier. The buffer can be bypassed by configuring the BOFFx bit in the
DAC_CR register.
84/115
DocID022265 Rev 4
STM32F051xx
6.3.18
Electrical characteristics
Comparator characteristics
Table 57. Comparator characteristics
Symbol
VDDA
Parameter
Conditions
Min(1) Typ Max(1)
Unit
Analog supply voltage
2
-
3.6
VIN
Comparator input
voltage range
0
-
VDDA
VBG
Scaler input voltage
-
1.2
-
VSC
Scaler offset voltage
-
±5
±10
mV
tS_SC
Scaler startup time
from power down
-
-
0.1
ms
tSTART
Comparator startup
time
Startup time to reach propagation delay
specification
-
-
60
μs
Ultra-low power mode
-
2
4.5
Low power mode
-
0.7
1.5
Medium power mode
-
0.3
0.6
VDDA  2.7 V
-
50
100
VDDA  2.7 V
-
100
240
Ultra-low power mode
-
2
7
Low power mode
-
0.7
2.1
Medium power mode
-
0.3
1.2
VDDA  2.7 V
-
90
180
VDDA  2.7 V
-
110
300
Propagation delay for
200 mV step with
100 mV overdrive
High speed mode
tD
Propagation delay for
full range step with
100 mV overdrive
High speed mode
V
μs
ns
μs
ns
Voffset
Comparator offset error
-
4
10
mV
dVoffset/dT
Offset error
temperature coefficient
-
18
-
μV/°C
Ultra-low power mode
-
1.2
1.5
Low power mode
-
3
5
Medium power mode
-
10
15
High speed mode
-
75
100
IDD(COMP)
COMP current
consumption
DocID022265 Rev 4
μA
85/115
94
Electrical characteristics
STM32F051xx
Table 57. Comparator characteristics (continued)
Symbol
Parameter
Min(1) Typ Max(1)
Conditions
No hysteresis
(COMPxHYST[1:0]=00)
Vhys
Comparator hysteresis
-
0
High speed mode
Low hysteresis
(COMPxHYST[1:0]=01) All other power
modes
3
High speed mode
Medium hysteresis
(COMPxHYST[1:0]=10) All other power
modes
7
High speed mode
High hysteresis
(COMPxHYST[1:0]=11) All other power
modes
18
Unit
13
8
5
10
26
15
9
mV
19
49
31
19
40
1. Data based on characterization results, not tested in production.
6.3.19
Temperature sensor characteristics
Table 58. TS characteristics
Symbol
Parameter
TL(1)
Typ
Max
Unit
-
1
2
°C
Average slope
4.0
4.3
4.6
mV/°C
Voltage at 30 °C (5 °C)(2)
1.34
1.43
1.52
V
4
-
10
μs
17.1
-
-
μs
VSENSE linearity with temperature
(1)
Avg_Slope
V30
tSTART
Min
(1)
TS_temp(1)(3)
Startup time
ADC sampling time when reading the
temperature
1. Guaranteed by design, not tested in production.
2. Measured at VDDA = 3.3 V 10 mV. The V30 ADC conversion result is stored in the TS_CAL1 byteRefer to
Table 3: Temperature sensor calibration values.
3. The shortest sampling time can be determined in the application by multiple iterations.
6.3.20
VBAT monitoring characteristics
Table 59. VBAT monitoring characteristics
Symbol
Parameter
Min
Typ
Max
Unit
k
R
Resistor bridge for VBAT
-
50
-
Q
Ratio on VBAT measurement
-
2
-
Error on Q
–1
-
+1
%
ADC sampling time when reading the VBAT
(for 1 mV accuracy)
5
-
-
μs
Er(1)
TS_vbat(1)(2)
1. Guaranteed by design, not tested in production.
2. The shortest sampling time can be determined in the application by multiple iterations.
86/115
DocID022265 Rev 4
STM32F051xx
6.3.21
Electrical characteristics
Timer characteristics
The parameters given in the following tables are guaranteed by design.
Refer to Section 6.3.14: I/O port characteristics for details on the input/output alternate
function characteristics (output compare, input capture, external clock, PWM output).
Table 60. TIMx(1) characteristics
Symbol
tres(TIM)
Parameter
Conditions
Timer resolution time
Min
Max
Unit
1
-
tTIMxCLK
20.8
-
ns
0
fTIMxCLK/2
MHz
0
24
MHz
TIMx (except
TIM2)
-
16
TIM2
-
32
1
65536
tTIMxCLK
0.0208
1365
μs
-
65536 × 65536
tTIMxCLK
-
89.48
s
fTIMxCLK = 48 MHz
Timer external clock
frequency on CH1 to CH4 f
TIMxCLK = 48 MHz
fEXT
ResTIM
tCOUNTER
tMAX_COUNT
Timer resolution
16-bit counter clock
period
fTIMxCLK = 48 MHz
Maximum possible count
with 32-bit counter
fTIMxCLK = 48 MHz
bit
1. TIMx is used as a general term to refer to the TIM1, TIM2, TIM3, TIM6, TIM14, TIM15, TIM16 and TIM17
timers.
Table 61. IWDG min/max timeout period at 40 kHz (LSI)(1)
Prescaler divider
PR[2:0] bits
Min timeout RL[11:0]=
0x000
Max timeout RL[11:0]=
0xFFF
/4
0
0.1
409.6
/8
1
0.2
819.2
/16
2
0.4
1638.4
/32
3
0.8
3276.8
/64
4
1.6
6553.6
/128
5
3.2
13107.2
/256
6 or 7
6.4
26214.4
Unit
ms
1. These timings are given for a 40 kHz clock but the microcontroller’s internal RC frequency can vary from
30 to 60 kHz. Moreover, given an exact RC oscillator frequency, the exact timings still depend on the
phasing of the APB interface clock versus the LSI clock so that there is always a full RC period of
uncertainty.
DocID022265 Rev 4
87/115
94
Electrical characteristics
STM32F051xx
Table 62. WWDG min/max timeout value at 48 MHz (PCLK)
6.3.22
Prescaler
WDGTB
Min timeout value
Max timeout value
1
0
0.0853
5.4613
2
1
0.1706
10.9226
4
2
0.3413
21.8453
8
3
0.6826
43.6906
Unit
ms
Communication interfaces
I2C interface characteristics
The I2C interface meets the requirements of the standard I2C communication protocol with
the following restrictions: the I/O pins SDA and SCL are mapped to are not “true” opendrain. When configured as open-drain, the PMOS connected between the I/O pin and
VDDIOx is disabled, but is still present.
The I2C characteristics are described in Table 63. Refer also to Section 6.3.14: I/O port
characteristics for more details on the input/output alternate function characteristics (SDA
and SCL).
Table 63. I2C characteristics(1)
Standard
Symbol
Fast mode
Fast mode +
Parameter
Unit
Min
Max
Min
Max
Min
Max
0
100
0
400
0
1000
KHz
-
1.3
-
0.5
-
μs
0.6
-
0.26
-
μs
fSCL
SCL clock frequency
tLOW
Low period of the SCL clock
4.7
tHIGH
High Period of the SCL clock
4
tr
Rise time of both SDA and SCL
signals
-
1000
-
300
-
120
ns
tf
Fall time of both SDA and SCL
signals
-
300
-
300
-
120
ns
tHD;DAT
Data hold time
0
-
0
-
0
-
μs
tVD;DAT
Data valid time
-
3.45(2)
-
0.9(2)
-
0.45(2)
μs
-
3.45(2)
-
0.9(2)
-
0.45(2)
μs
tVD;ACK
Data valid acknowledge time
tSU;DAT
Data setup time
250
-
100
-
50
-
ns
tHD;STA
Hold time (repeated) START
condition
4.0
-
0.6
-
0.26
-
μs
tSU;STA
Set-up time for a repeated
START
condition
4.7
-
0.6
-
0.26
-
μs
tSU;STO
Set-up time for STOP condition
4.0
-
0.6
-
0.26
-
μs
Bus free time between a
STOP and START condition
4.7
-
1.3
-
0.5
-
μs
tBUF
88/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 63. I2C characteristics(1) (continued)
Standard
Symbol
Fast mode
Fast mode +
Parameter
Unit
Min
Max
Min
Max
Min
Max
Cb
Capacitive load for each bus line
-
400
-
400
-
550
pF
tSP
Pulse width of spikes that are
suppressed by the analog filter
0
50(3)
0
50(3)
0
50(3)
ns
1. The I2C characteristics are the requirements from the I2C bus specification rev03. They are guaranteed by design when
the I2Cx_TIMING register is correctly programmed (refer to reference manual). These characteristics are not tested in
production.
2. The maximum tHD;DAT could be 3.45 μs, 0.9 μs and 0.45 μs for standard mode, fast mode and fast mode plus, but must be
less than the maximum of tVD;DAT or tVD;ACK by a transition time.
3. The minimum width of the spikes filtered by the analog filter is above tSP(max).
Table 64. I2C analog filter characteristics(1)
Symbol
Parameter
Min
Max
Unit
tAF
Maximum pulse width of spikes
that are suppressed by the analog
filter
50(2)
260(3)
ns
1. Guaranteed by design, not tested in production.
2. Spikes with widths below tAF(min) are filtered.
3. Spikes with widths above tAF(max) are not filtered
DocID022265 Rev 4
89/115
94
Electrical characteristics
STM32F051xx
Figure 27. I2C bus AC waveforms and measurement circuit
9''B,&
9''B,&
5S
5S
0&8
5V
6'$
,&EXV
5V
6&/
UG
4%"
U 46%"5
US
UG
U )%45"
US
DPOUJOVFE
U -08
G4$-
4
U 7%%"5
U )*()
4$-
DPOUJOVFE
U )%%"5
UIDMPDL
U #6'
TUDMPDLDZDMF
4%"
U 4645"
U )%45"
U 7%"$,
U 41
U 46450
4$4S
UIDMPDL
1
4
069
Legend: Rs: Series protection resistors. Rp: Pull-up resistors. VDD_I2C: I2C bus supply.
SPI/I2S characteristics
Unless otherwise specified, the parameters given in Table 65 for SPI or in Table 66 for I2S
are derived from tests performed under the ambient temperature, fPCLKx frequency and
supply voltage conditions summarized in Table 20: General operating conditions.
Refer to Section 6.3.14: I/O port characteristics for more details on the input/output alternate
function characteristics (NSS, SCK, MOSI, MISO for SPI and WS, CK, SD for I2S).
Table 65. SPI characteristics(1)
Symbol
fSCK
1/tc(SCK)
tr(SCK)
tf(SCK)
90/115
Parameter
SPI clock frequency
SPI clock rise and fall
time
Conditions
Min
Max
Master mode
-
18
Slave mode
-
18
Capacitive load: C = 15 pF
-
6
DocID022265 Rev 4
Unit
MHz
ns
STM32F051xx
Electrical characteristics
Table 65. SPI characteristics(1) (continued)
Symbol
Parameter
Conditions
Min
Max
tsu(NSS)
NSS setup time
Slave mode
4Tpclk
-
th(NSS)
NSS hold time
Slave mode
2Tpclk + 10
-
SCK high and low time
Master mode, fPCLK = 36 MHz,
presc = 4
Tpclk/2 -2
Tpclk/2 + 1
Master mode
4
-
Slave mode
5
-
Master mode
4
-
Slave mode
5
-
tw(SCKH)
tw(SCKL)
tsu(MI)
tsu(SI)
Data input setup time
th(MI)
Data input hold time
th(SI)
ta(SO)(2)
Data output access time
Slave mode, fPCLK = 20 MHz
0
3Tpclk
tdis(SO)(3)
Data output disable time
Slave mode
0
18
tv(SO)
Data output valid time
Slave mode (after enable edge)
-
22.5
tv(MO)
Data output valid time
Master mode (after enable edge)
-
6
Slave mode (after enable edge)
11.5
-
Master mode (after enable edge)
2
-
Slave mode
25
75
th(SO)
Data output hold time
th(MO)
DuCy(SCK)
SPI slave input clock
duty cycle
Unit
ns
%
1. Data based on characterization results, not tested in production.
2. Min time is for the minimum time to drive the output and the max time is for the maximum time to validate the data.
3. Min time is for the minimum time to invalidate the output and the max time is for the maximum time to put the data in Hi-Z
Figure 28. SPI timing diagram - slave mode and CPHA = 0
.33INPUT
TC3#+
TH.33
3#+)NPUT
T35.33
#0(! #0/,
#0(! #0/,
TW3#+(
TW3#+,
TV3/
TA3/
-)3/
/54 0 54
-3 " / 54
TH3/
") 4 /54
TR3#+
TF3#+
TDIS3/
,3" /54
TSU3)
-/3)
) .054
- 3" ).
" ) 4 ).
,3" ).
TH3)
AIC
DocID022265 Rev 4
91/115
94
Electrical characteristics
STM32F051xx
Figure 29. SPI timing diagram - slave mode and CPHA = 1
.33INPUT
3#+)NPUT
T35.33
#0(!
#0/,
TC3#+
TH.33
TW3#,(
TW3#,,
#0(!
#0/,
TV3/
TA3/
-)3/
/54 0 54
TH3/
-3 " / 54
TSU3)
-/3)
) .054
TR3#,
TF3#,
") 4 /54
TDIS3/
,3" /54
TH3)
" ) 4 ).
- 3" ).
,3" ).
AI
1. Measurement points are done at CMOS levels: 0.3 VDD and 0.7 VDD.
Figure 30. SPI timing diagram - master mode
(IGH
.33INPUT
3#+/UTPUT
#0(! #0/,
3#+/UTPUT
TC3#+
#0(!
#0/,
#0(! #0/,
#0(!
#0/,
TSU-)
-)3/
).0 54
TW3#+(
TW3#+,
TR3#+
TF3#+
-3 ").
") 4).
,3").
TH-)
-/3)
/54054
- 3"/54
TV-/
" ) 4/54
,3"/54
TH-/
AI6
1. Measurement points are done at CMOS levels: 0.3 VDD and 0.7 VDD.
92/115
DocID022265 Rev 4
STM32F051xx
Electrical characteristics
Table 66. I2S characteristics(1)
Symbol
fCK
1/tc(CK)
Parameter
2
I S clock frequency
I2S clock rise time
tr(CK)
Conditions
Min
Max
1.597
1.601
Slave mode
0
6.5
Capacitive load CL = 15 pF
-
10
-
12
306
-
312
-
Master mode (data: 16 bits, Audio
frequency = 48 kHz)
2
I S clock fall time
tf(CK)
Master fPCLK= 16 MHz, audio
frequency = 48 kHz
tw(CKH)
I2S clock high time
tw(CKL)
I2S clock low time
tv(WS)
WS valid time
Master mode
2
-
th(WS)
WS hold time
Master mode
2
-
tsu(WS)
WS setup time
Slave mode
7
-
th(WS)
WS hold time
Slave mode
0
-
I2S slave input clock duty
cycle
Slave mode
25
75
tsu(SD_MR)
Data input setup time
Master receiver
6
-
tsu(SD_SR)
Data input setup time
Slave receiver
2
-
Master receiver
4
-
Slave receiver
0.5
-
-
20
13
-
-
4
0
-
DuCy(SCK)
th(SD_MR)
(2)
th(SD_SR)(2)
Data input hold time
tv(SD_ST)(2)
Data output valid time
th(SD_ST)
Data output hold time
tv(SD_MT)
(2)
th(SD_MT)
Data output valid time
Data output hold time
Slave transmitter (after enable edge)
Slave transmitter (after enable edge)
Master transmitter (after enable edge)
Master transmitter (after enable edge)
Unit
MHz
ns
%
ns
1. Data based on design simulation and/or characterization results, not tested in production.
2. Depends on fPCLK. For example, if fPCLK = 8 MHz, then TPCLK = 1/fPLCLK = 125 ns.
DocID022265 Rev 4
93/115
94
Electrical characteristics
STM32F051xx
Figure 31. I2S slave timing diagram (Philips protocol)
#+)NPUT
TC#+
#0/,
#0/,
TW#+(
TH73
TW#+,
73INPUT
TV3$?34
TSU73
3$TRANSMIT
,3"TRANSMIT
-3"TRANSMIT
"ITNTRANSMIT
TSU3$?32
,3"RECEIVE
3$RECEIVE
TH3$?34
,3"TRANSMIT
TH3$?32
-3"RECEIVE
"ITNRECEIVE
,3"RECEIVE
AIB
1. Measurement points are done at CMOS levels: 0.3 × VDDIOx and 0.7 × VDDIOx.
2. LSB transmit/receive of the previously transmitted byte. No LSB transmit/receive is sent before the first
byte.
Figure 32. I2S master timing diagram (Philips protocol)
TF#+
TR#+
#+OUTPUT
TC#+
#0/,
TW#+(
#0/,
TV73
TH73
TW#+,
73OUTPUT
TV3$?-4
3$TRANSMIT
,3"TRANSMIT
-3"TRANSMIT
,3"RECEIVE
,3"TRANSMIT
TH3$?-2
TSU3$?-2
3$RECEIVE
"ITNTRANSMIT
TH3$?-4
-3"RECEIVE
"ITNRECEIVE
,3"RECEIVE
AIB
1. Data based on characterization results, not tested in production.
2. LSB transmit/receive of the previously transmitted byte. No LSB transmit/receive is sent before the first
byte.
94/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
7
Package characteristics
7.1
Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
DocID022265 Rev 4
95/115
110
Package characteristics
STM32F051xx
Figure 33. LQFP64 – 10 x 10 mm 64 pin low-profile quad flat package outline
!
C
!
!
3%!4).'
0,!.%
#
MM
'!5'%0,!.%
!
CCC #
+
,
$
,
$
$
0).
)$%.4)&)#!4)/.
%
%
%
B
E
7?-%?6
1. Drawing is not to scale.
Table 67. LQFP64 – 10 x 10 mm 64 pin low-profile quad flat package mechanical data
inches(1)
millimeters
Symbol
Min
Typ
Max
Min
Typ
Max
A
-
-
1.600
-
-
0.0630
A1
0.050
-
0.150
0.0020
-
0.0059
A2
1.350
1.400
1.450
0.0531
0.0551
0.0571
b
0.170
0.220
0.270
0.0067
0.0087
0.0106
c
0.090
-
0.200
0.0035
-
0.0079
D
11.800
12.000
12.200
0.4646
0.4724
0.4803
D1
9.800
10.000
10.200
0.3858
0.3937
0.4016
D.
-
7.500
-
-
-
-
96/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
Table 67. LQFP64 – 10 x 10 mm 64 pin low-profile quad flat package mechanical data (continued)
inches(1)
millimeters
Symbol
Min
Typ
Max
Min
Typ
Max
E
11.800
12.000
12.200
0.4646
0.4724
0.4803
E1
9.800
10.000
10.200
0.3858
0.3937
0.4016
e
-
0.500
-
-
0.0197
-
k
0°
3.5°
7°
0°
3.5°
7°
L
0.450
0.600
0.750
0.0177
0.0236
0.0295
L1
-
1.000
-
-
0.0394
-
ccc
0.080
0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Figure 34. LQFP64 recommended footprint
AIC
1. Drawing is not to scale.
2. Dimensions are in millimeters.
DocID022265 Rev 4
97/115
110
Package characteristics
STM32F051xx
Figure 35. LQFP48 – 7 x 7 mm, 48 pin low-profile quad flat package outline
C
!
!
!
3%!4).'
0,!.%
#
MM
'!5'%0,!.%
CCC #
+
!
$
$
,
,
$
0).
)$%.4)&)#!4)/.
%
%
%
B
E
"?-%?6
1. Drawing is not to scale.
Table 68. LQFP48 – 7 x 7 mm, 48-pin low-profile quad flat package mechanical data
Symbol
inches(1)
millimeters
Min
Typ
Max
Min
Typ
Max
A
-
-
1.600
-
-
0.0630
A1
0.050
-
0.150
0.0020
-
0.0059
A2
1.350
1.400
1.450
0.0531
0.0551
0.0571
b
0.170
0.220
0.270
0.0067
0.0087
0.0106
c
0.090
-
0.200
0.0035
-
0.0079
D
8.800
9.000
9.200
0.3465
0.3543
0.3622
D1
6.800
7.000
7.200
0.2677
0.2756
0.2835
D3
-
5.500
-
-
0.2165
-
E
8.800
9.000
9.200
0.3465
0.3543
0.3622
E1
6.800
7.000
7.200
0.2677
0.2756
0.2835
E3
-
5.500
-
-
0.2165
-
e
-
0.500
-
-
0.0197
-
L
0.450
0.600
0.750
0.0177
0.0236
0.0295
98/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
Table 68. LQFP48 – 7 x 7 mm, 48-pin low-profile quad flat package mechanical data (continued)
Symbol
inches(1)
millimeters
Min
Typ
Max
Min
Typ
Max
L1
-
1.000
-
-
0.0394
-
k
0°
3.5°
7°
0°
3.5°
7°
ccc
0.080
0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Figure 36. LQFP48 recommended footprint
AID
1. Drawing is not to scale.
2. Dimensions are in millimeters.
DocID022265 Rev 4
99/115
110
Package characteristics
STM32F051xx
Figure 37. LQFP32 – 7 x 7mm 32-pin low-profile quad flat package outline
C
!
!
!
3%!4).'
0,!.%
#
MM
CCC
'!5'%0,!.%
#
+
$
!
,
$
,
$
0).
)$%.4)&)#!4)/.
%
%
%
B
E
[email protected]&@7
1. Drawing is not to scale.
Table 69. LQFP32 – 7 x 7mm 32-pin low-profile quad flat package mechanical data
inches(1)
millimeters
Symbol
100/115
Min
Typ
Max
Min
Typ
Max
A
-
-
1.600
-
-
0.0630
A1
0.050
-
0.150
0.0020
-
0.0059
A2
1.350
1.400
1.450
0.0531
0.0551
0.0571
b
0.300
0.370
0.450
0.0118
0.0146
0.0177
c
0.090
-
0.200
0.0035
-
0.0079
D
8.800
9.000
9.200
0.3465
0.3543
0.3622
DocID022265 Rev 4
STM32F051xx
Package characteristics
Table 69. LQFP32 – 7 x 7mm 32-pin low-profile quad flat package mechanical data (continued)
inches(1)
millimeters
Symbol
Min
Typ
Max
Min
Typ
Max
D1
6.800
7.000
7.200
0.2677
0.2756
0.2835
D3
-
5.600
-
-
0.2205
-
E
8.800
9.000
9.200
0.3465
0.3543
0.3622
E1
6.800
7.000
7.200
0.2677
0.2756
0.2835
E3
-
5.600
-
-
0.2205
-
e
-
0.800
-
-
0.0315
-
L
0.450
0.600
0.750
0.0177
0.0236
0.0295
L1
-
1.000
-
-
0.0394
-
k
0.0°
3.5°
7.0°
0.0°
3.5°
7.0°
ccc
-
-
0.100
-
-
0.0039
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Figure 38. LQFP32 recommended footprint
6?&0?6
1. Drawing is not to scale.
2. Dimensions are in millimeters.
DocID022265 Rev 4
101/115
110
Package characteristics
STM32F051xx
Figure 39. UFBGA64 - 5 x 5 mm, 0.5 mm pitch, package outline
= 6HDWLQJSODQH
GGG =
$
$ $
$ $
(
H
$EDOO
$EDOO
LGHQWLILHU LQGH[DUHD
)
;
(
$
)
'
'
H
<
+
%277209,(:
‘EEDOOV
‘ HHH 0 = < ;
‘ III 0 =
1. Drawing is not to scale.
102/115
DocID022265 Rev 4
7239,(:
5EB0(B9
STM32F051xx
Package characteristics
Table 70. UFBGA64 – 5 x 5 mm, 0.5 mm pitch, package mechanical data(1)
inches(2)
millimeters
Symbol
Min
Typ
Max
Min
Typ
Max
A
0.460
0.530
0.600
0.0181
0.0209
0.0236
A1
0.050
0.080
0.110
0.0020
0.0031
0.0043
A2
0.400
0.450
0.500
0.0157
0.0177
0.0197
A3
0.080
0.130
0.180
0.0031
0.0051
0.0071
A4
0.270
0.320
0.370
0.0106
0.0126
0.0146
b
0.170
0.280
0.330
0.0067
0.0110
0.0130
D
4.850
5.000
5.150
0.1909
0.1969
0.2028
D1
3.450
3.500
3.550
0.1358
0.1378
0.1398
E
4.850
5.000
5.150
0.1909
0.1969
0.2028
E1
3.450
3.500
3.550
0.1358
0.1378
0.1398
e
-
0.500
-
-
0.0197
-
F
0.700
0.750
0.800
0.0276
0.0295
0.0315
ddd
-
-
0.080
-
-
0.0031
eee
-
-
0.150
-
-
0.0059
fff
-
-
0.050
-
-
0.0020
1. Preliminary data.
2. Values in inches are converted from mm and rounded to 4 decimal digits.
DocID022265 Rev 4
103/115
110
Package characteristics
STM32F051xx
Figure 40. UFQFPN48 – 7 x 7 mm, 0.5 mm pitch, package outline
3LQLGHQWLILHU
ODVHUPDUNLQJDUHD
'
$
(
(
7
GGG
$
6HDWLQJ
SODQH
E
H
'HWDLO<
'
([SRVHGSDG
DUHD
<
'
/
&[ƒ
SLQFRUQHU
(
5W\S
'HWDLO=
=
$%B0(B9
1. Drawing is not to scale.
2. All leads/pads should also be soldered to the PCB to improve the lead/pad solder joint life.
3. There is an exposed die pad on the underside of the UFQFPN package. It is recommended to connect and
solder this back-side pad to PCB ground.
104/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
Table 71. UFQFPN48 – 7 x 7 mm, 0.5 mm pitch, package mechanical data
inches(1)
millimeters
Symbol
Min
Typ
Max
Min
Typ
Max
A
0.500
0.550
0.600
0.0197
0.0217
0.0236
A1
0.000
0.020
0.050
0.0000
0.0008
0.0020
D
6.900
7.000
7.100
0.2717
0.2756
0.2795
E
6.900
7.000
7.100
0.2717
0.2756
0.2795
D2
5.500
5.600
5.700
0.2165
0.2205
0.2244
E2
5.500
5.600
5.700
0.2165
0.2205
0.2244
L
0.300
0.400
0.500
0.0118
0.0157
0.0197
T
-
0.152
-
-
0.0060
-
b
0.200
0.250
0.300
0.0079
0.0098
0.0118
e
-
0.500
-
-
0.0197
-
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Figure 41. UFQFPN48 recommended footprint
!"?&0?6
1. Dimensions are in millimeters.
DocID022265 Rev 4
105/115
110
Package characteristics
STM32F051xx
Figure 42. UFQFPN32 – 32-lead ultra thin fine pitch quad flat no-lead package outline
(5 x 5)
!"?-%?6
1. Drawing is not to scale.
2. All leads/pads should also be soldered to the PCB to improve the lead/pad solder joint life.
3. There is an exposed die pad on the underside of the UFQFPN package. This pad is used for the device
ground and must be connected. It is referred to as Pin 0 in Table 13: Pin definitions.
106/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
Table 72. UFQFPN32 – 32-lead ultra thin fine pitch quad flat no-lead package (5 x 5),
package mechanical data
inches(1)
mm
Dim.
Min
Typ
Max
Min
Typ
Max
A
0.500
0.550
0.600
0.0197
0.0217
0.0236
A1
0
0.020
0.050
0
0.0008
0.0020
A3
-
0.152
-
-
0.006
-
b
0.180
0.230
0.280
0.0071
0.0091
0.0110
D
4.900
5.000
5.100
0.1929
0.1969
0.2008
D2
-
3.500
-
-
0.1378
-
E
4.900
5.000
5.100
0.1929
0.1969
0.2008
E2
3.400
3.500
3.600
0.1339
0.1378
0.1417
e
-
0.500
-
-
0.0197
-
L
0.300
0.400
0.500
0.0118
0.0157
0.0197
ddd
0.0800
0.0031
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Figure 43. UFQFPN32 recommended footprint
$%B)3B9
1. Drawing is not to scale.
2. Dimensions are in millimeters.
DocID022265 Rev 4
107/115
110
Package characteristics
7.2
STM32F051xx
Thermal characteristics
The maximum chip junction temperature (TJmax) must never exceed the values given in
Table 20: General operating conditions.
The maximum chip-junction temperature, TJ max, in degrees Celsius, may be calculated
using the following equation:
TJ max = TA max + (PD max x JA)
Where:

TA max is the maximum ambient temperature in °C,

JA is the package junction-to-ambient thermal resistance, in C/W,

PD max is the sum of PINT max and PI/O max (PD max = PINT max + PI/Omax),

PINT max is the product of IDD and VDD, expressed in Watts. This is the maximum chip
internal power.
PI/O max represents the maximum power dissipation on output pins where:
PI/O max = (VOL × IOL) + ((VDDIOx – VOH) × IOH),
taking into account the actual VOL / IOL and VOH / IOH of the I/Os at low and high level in the
application.
Table 73. Package thermal characteristics
Symbol
JA
7.2.1
Parameter
Value
Thermal resistance junction-ambient
LQFP64 - 10 × 10 mm / 0.5 mm pitch
45
Thermal resistance junction-ambient
LQFP48 - 7 × 7 mm
55
Thermal resistance junction-ambient
LQFP32 - 7 × 7 mm
56
Thermal resistance junction-ambient
UFBGA64 - 5 × 5 mm
65
Thermal resistance junction-ambient
UFQFPN48 - 7 × 7 mm
32
Thermal resistance junction-ambient
UFQFPN32 - 5 × 5 mm
38
Unit
°C/W
Reference document
JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural
Convection (Still Air). Available from www.jedec.org
7.2.2
Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the ordering
information scheme shown in Section 8: Part numbering.
Each temperature range suffix corresponds to a specific guaranteed ambient temperature at
maximum dissipation and, to a specific maximum junction temperature.
108/115
DocID022265 Rev 4
STM32F051xx
Package characteristics
As applications do not commonly use the STM32F0xx at maximum dissipation, it is useful to
calculate the exact power consumption and junction temperature to determine which
temperature range will be best suited to the application.
The following examples show how to calculate the temperature range needed for a given
application.
Example 1: High-performance application
Assuming the following application conditions:
Maximum ambient temperature TAmax = 82 °C (measured according to JESD51-2),
IDDmax = 50 mA, VDD = 3.5 V, maximum 20 I/Os used at the same time in output at low
level with IOL = 8 mA, VOL= 0.4 V and maximum 8 I/Os used at the same time in output
at low level with IOL = 20 mA, VOL= 1.3 V
PINTmax = 50 mA × 3.5 V= 175 mW
PIOmax = 20 × 8 mA × 0.4 V + 8 × 20 mA × 1.3 V = 272 mW
This gives: PINTmax = 175 mW and PIOmax = 272 mW:
PDmax = 175 + 272 = 447 mW
Using the values obtained in Table 73 TJmax is calculated as follows:
–
For LQFP64, 45 °C/W
TJmax = 82 °C + (45 °C/W × 447 mW) = 82 °C + 20.115 °C = 102.115 °C
This is within the range of the suffix 6 version parts (–40 < TJ < 105 °C) see Table 20:
General operating conditions.
In this case, parts must be ordered at least with the temperature range suffix 6 (see
Section 8: Part numbering).
Note:
With this given PDmax we can find the TAmax allowed for a given device temperature range
(order code suffix 6 or 7).
Suffix 6: TAmax = TJmax - (45°C/W × 447 mW) = 105-20.115 = 84.885 °C
Suffix 7: TAmax = TJmax - (45°C/W × 447 mW) = 125-20.115 = 104.885 °C
Example 2: High-temperature application
Using the same rules, it is possible to address applications that run at high ambient
temperatures with a low dissipation, as long as junction temperature TJ remains within the
specified range.
Assuming the following application conditions:
Maximum ambient temperature TAmax = 100 °C (measured according to JESD51-2),
IDDmax = 20 mA, VDD = 3.5 V, maximum 20 I/Os used at the same time in output at low
level with IOL = 8 mA, VOL= 0.4 V
PINTmax = 20 mA × 3.5 V= 70 mW
PIOmax = 20 × 8 mA × 0.4 V = 64 mW
This gives: PINTmax = 70 mW and PIOmax = 64 mW:
PDmax = 70 + 64 = 134 mW
Thus: PDmax = 134 mW
DocID022265 Rev 4
109/115
110
Package characteristics
STM32F051xx
Using the values obtained in Table 73 TJmax is calculated as follows:
–
For LQFP64, 45 °C/W
TJmax = 100 °C + (45 °C/W × 134 mW) = 100 °C + 6.03 °C = 106.03 °C
This is above the range of the suffix 6 version parts (–40 < TJ < 105 °C).
In this case, parts must be ordered at least with the temperature range suffix 7 (see
Section 8: Part numbering) unless we reduce the power dissipation in order to be able to
use suffix 6 parts.
Refer to Figure 44 to select the required temperature range (suffix 6 or 7) according to your
ambient temperature or power requirements.
Figure 44. LQFP64 PD max vs. TA
3'P:
6XIIL[
6XIIL[
7$ƒ&
110/115
DocID022265 Rev 4
06Y9
STM32F051xx
8
Part numbering
Part numbering
For a list of available options (memory, package, and so on) or for further information on any
aspect of this device, please contact your nearest ST sales office.
Table 74. Ordering information scheme
Example:
STM32
F
051 R
8
T
6
x
Device family
STM32 = ARM-based 32-bit microcontroller
Product type
F = General-purpose
Sub-family
051 = STM32F051xx
Pin count
K = 32 pins
C = 48 pins
R = 64 pins
Code size
4 = 16 Kbytes of Flash memory
6 = 32 Kbytes of Flash memory
8 = 64 Kbytes of Flash memory
Package
H = UFBGA
T = LQFP
U = UFQFPN
Temperature range
6 = –40 °C to +85 °C
7 = –40 °C to +105 °C
Options
xxx = programmed parts
TR = tape and reel
DocID022265 Rev 4
111/115
111
Revision history
9
STM32F051xx
Revision history
Table 75. Document revision history
Date
Revision
05-Apr-2012
1
Initial release
2
Updated Table 2: STM32F051xx family device features and
peripheral counts for 1 SPI and 1 I2C in 32-pin package
Corrected Group 3 pin order in Table 5: Capacitive sensing
GPIOs available on STM32F051xx devices.
Updated current consumptionTable 25 to Table 28.
Updated Table 39: HSI14 oscillator characteristics
3
Features reorganized and Section Figure 1.: Block diagram
structure changed.
Added LQFP32 package.
Updated Section 3.4: Cyclic redundancy check calculation
unit (CRC).
Modified number of priority levels in Section 3.9.1: Nested
vectored interrupt controller (NVIC).
Added note 3. for PB2 and PB8, changed TIM2_CH_ETR into
TIM2_CH1_ETR in Table 13: Pin definitions and Table 14:
Alternate functions selected through GPIOA_AFR registers
for port A. Added Table 15: Alternate functions selected
through GPIOB_AFR registers for port B.
Updated IVDD, IVSS, and IINJ(PIN) in Table 18: Current
characteristics.
Updated ACCHSI in Table 38: HSI oscillator characteristics
and Table 39: HSI14 oscillator characteristics.
Updated Table 48: I/O current injection susceptibility.
Added BOOT0 input low and high level voltage in Table 49:
I/O static characteristics.
Modified number of pins in VOL and VOH description, and
changed condition for VOLFM+ in Table 50: Output voltage
characteristics.
Changed VDD to VDDA in Figure 37: Typical connection
diagram using the ADC.
Updated Ts_temp in Table 58: TS characteristics.
Updated Figure 27: I2C bus AC waveforms and measurement
circuit.
25-Apr-2012
23-Jul-2012
112/115
Changes
DocID022265 Rev 4
STM32F051xx
Revision history
Table 75. Document revision history (continued)
Date
13-Jan-2014
Revision
4
Changes
Modified datasheet title.
Added packages UFQFPN48 and UFBGA64.
Replaced “backup domain with “RTC domain” throughout the
document.
Changed SRAM value from “4 to 8 Kbytes” to “8 Kbytes”
Replaced IWWDG with IWDG in Figure 1: Block diagram.
Added inputs LSI and LSE to the multiplexer in Figure 2:
Clock tree.
Added feature “Reference clock detection” in Section 3.15:
Real-time clock (RTC) and backup registers.
Modified junction temperature in Table 2: STM32F051xx
family device features and peripheral counts.
Renamed Table 4: Internal voltage reference calibration
values.
Replaced VDD with VDDA and VRERINT with VREFINT in
Table 24: Embedded internal reference voltage.
Rephrased introduction of Section 3.13: Touch sensing
controller (TSC).
Rephrased Section 3.5.3: Voltage regulator.
Added sentence “If this is used when the voltage regulator is
put in low power mode...” under “Stop mode” in Section 3.5.4:
Low-power modes.
Removed sentence “The internal voltage reference is also
connected to ADC_IN17 input channel of the ADC.” in
Section 3.12: Comparators (COMP).
Removed feature “Periodic wakeup from Stop/Standby” in
Section 3.15: Real-time clock (RTC) and backup registers.
Replaced IDD with IDDA in Table 38: HSI oscillator
characteristics, Table 39: HSI14 oscillator characteristics and
Table 40: LSI oscillator characteristics.
Moved section “Wakeup time from low-power mode” to
Section 6.3.6 and rephrased the section.
Added lines D2 and E2 in Table 71: UFQFPN48 – 7 x 7 mm,
0.5 mm pitch, package mechanical data.
Added “The peripheral clock used is 48 MHz.” in Section Onchip peripheral current consumption.
DocID022265 Rev 4
113/115
114
Revision history
STM32F051xx
Table 75. Document revision history (continued)
Date
13-Jan-2014
114/115
Revision
Changes
4
(continued)
Added “Negative induced leakage current is caused by
negative injection and positive induced leakage current is
caused by positive injection” in Section Functional
susceptibility to I/O current injection.
Replaced reference "JESD22-C101" with "ANSI/ESD
STM5.3.1" in Table 46: ESD absolute maximum ratings.
Merged Table 27: Typical and maximum VDD consumption in
Stop and Standby modes and Table 28: Typical and maximum
VDDA consumption in Stop and Standby modes into Table 27:
Typical and maximum current consumption in Stop and
Standby modes.
Updated:
– Table 3: Temperature sensor calibration values
– Table 4: Internal voltage reference calibration values
– Table 18: Current characteristics
– Table 20: General operating conditions
– Table 26: Typical and maximum current consumption from
the VDDA supply
– Table 33: Low-power mode wakeup timings
– Table 48: I/O current injection susceptibility
– Table 49: I/O static characteristics
– Table 50: Output voltage characteristics
– Table 52: NRST pin characteristics
– Table 63: I2C characteristics
– Figure 12: Power supply scheme
– Figure 20: TC and TTa I/O input characteristics
– Figure 21: Five volt tolerant (FT and FTf) I/O input
characteristics
– Figure 22: I/O AC characteristics definition
– Figure 27: I2C bus AC waveforms and measurement circuit
– Figure 25: Typical connection diagram using the ADC
– Figure 33: LQFP64 – 10 x 10 mm 64 pin low-profile quad
flat package outline
– Figure 34: LQFP64 recommended footprint
– Figure 35: LQFP48 – 7 x 7 mm, 48 pin low-profile quad flat
package outline
– Figure 36: LQFP48 recommended footprint
– Figure 37: LQFP32 – 7 x 7mm 32-pin low-profile quad flat
package outline
– Figure 38: LQFP32 recommended footprint
– Figure 40: UFQFPN48 – 7 x 7 mm, 0.5 mm pitch, package
outline
DocID022265 Rev 4
STM32F051xx
Please Read Carefully:
Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.
All ST products are sold pursuant to ST’s terms and conditions of sale.
Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no
liability whatsoever relating to the choice, selection or use of the ST products and services described herein.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this
document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products
or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such
third party products or services or any intellectual property contained therein.
UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED
WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS
OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.
ST PRODUCTS ARE NOT DESIGNED OR AUTHORIZED FOR USE IN: (A) SAFETY CRITICAL APPLICATIONS SUCH AS LIFE
SUPPORTING, ACTIVE IMPLANTED DEVICES OR SYSTEMS WITH PRODUCT FUNCTIONAL SAFETY REQUIREMENTS; (B)
AERONAUTIC APPLICATIONS; (C) AUTOMOTIVE APPLICATIONS OR ENVIRONMENTS, AND/OR (D) AEROSPACE APPLICATIONS
OR ENVIRONMENTS. WHERE ST PRODUCTS ARE NOT DESIGNED FOR SUCH USE, THE PURCHASER SHALL USE PRODUCTS AT
PURCHASER’S SOLE RISK, EVEN IF ST HAS BEEN INFORMED IN WRITING OF SUCH USAGE, UNLESS A PRODUCT IS
EXPRESSLY DESIGNATED BY ST AS BEING INTENDED FOR “AUTOMOTIVE, AUTOMOTIVE SAFETY OR MEDICAL” INDUSTRY
DOMAINS ACCORDING TO ST PRODUCT DESIGN SPECIFICATIONS. PRODUCTS FORMALLY ESCC, QML OR JAN QUALIFIED ARE
DEEMED SUITABLE FOR USE IN AEROSPACE BY THE CORRESPONDING GOVERNMENTAL AGENCY.
Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void
any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any
liability of ST.
ST and the ST logo are trademarks or registered trademarks of ST in various countries.
Information in this document supersedes and replaces all information previously supplied.
The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners.
© 2014 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
www.st.com
DocID022265 Rev 4
115/115
115
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement