TMS320C5515/14/05/04 DSP Real-Time Clock

TMS320C5515/14/05/04 DSP
Real-Time Clock (RTC)
User's Guide
Literature Number: SPRUFX2A
March 2010 – Revised May 2014
Contents
Preface ........................................................................................................................................ 5
1
Real-Time Clock (RTC)
1.1
1.2
1.3
......................................................................................................... 8
Introduction ................................................................................................................... 9
1.1.1 Purpose of the Peripheral.......................................................................................... 9
1.1.2 Features .............................................................................................................. 9
1.1.3 Functional Block Diagram ........................................................................................ 10
Peripheral Architecture .................................................................................................... 10
1.2.1 Clock Control....................................................................................................... 10
1.2.2 Signal Descriptions ................................................................................................ 10
1.2.3 RTC-Only Mode ................................................................................................... 11
1.2.4 Using the Real-Time Clock Time and Calendar Registers .................................................. 11
1.2.5 Using the Real-Time Clock Time and Calendar Alarms ..................................................... 13
1.2.6 Real-Time Clock Interrupt Requests ............................................................................ 14
1.2.7 Reset Considerations ............................................................................................. 17
Registers .................................................................................................................... 18
1.3.1 Overview............................................................................................................ 18
1.3.2 RTC Registers ..................................................................................................... 18
Revision History .......................................................................................................................... 35
2
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List of Figures
1-1.
Block Diagram .............................................................................................................. 10
1-2.
RTC Interrupt and Wakeup Logic ........................................................................................ 16
1-3.
RTCINTEN Register ....................................................................................................... 20
1-4.
RTCUPDATE Register
20
1-5.
RTCMIL Register
21
1-6.
1-7.
1-8.
1-9.
1-10.
1-11.
1-12.
1-13.
1-14.
1-15.
1-16.
1-17.
1-18.
1-19.
1-20.
1-21.
1-22.
1-23.
1-24.
1-25.
1-26.
1-27.
1-28.
....................................................................................................
..........................................................................................................
RTCMILA Register (RTCMILA) ...........................................................................................
RTCSEC Register ..........................................................................................................
RTCSECA Register .......................................................................................................
RTCMIN Register ..........................................................................................................
RTCMINA Register .........................................................................................................
RTCHOUR Register .......................................................................................................
RTCHOURA Register ......................................................................................................
RTCDAY Register ..........................................................................................................
RTCDAYA Register ........................................................................................................
RTCMONTH Register .....................................................................................................
RTCMONTHA Register ....................................................................................................
RTCYEAR Register .......................................................................................................
RTCYEARA Register ......................................................................................................
RTCINTFL Register ........................................................................................................
RTCNOPWR Register .....................................................................................................
RTCINTREG Register .....................................................................................................
RTCDRIFT Register .......................................................................................................
RTCOSC Register..........................................................................................................
RTCPMGT Register........................................................................................................
RTCSCR1 Register ........................................................................................................
RTCSCR2 Register ........................................................................................................
RTCSCR3 Register ........................................................................................................
RTCSCR4 Register ........................................................................................................
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List of Figures
21
22
22
23
23
24
24
25
25
26
26
27
27
28
29
30
31
31
32
33
33
34
34
3
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List of Tables
1-1.
Time/Calendar Registers .................................................................................................. 12
1-2.
Time and Calendar Alarm Data
1-3.
1-4.
1-5.
1-6.
1-7.
1-8.
1-9.
1-10.
1-11.
1-12.
1-13.
1-14.
1-15.
1-16.
1-17.
1-18.
1-19.
1-20.
1-21.
1-22.
1-23.
1-24.
1-25.
1-26.
1-27.
1-28.
1-29.
1-30.
1-31.
4
..........................................................................................
Time/Calendar Alarm Settings ............................................................................................
Periodic Interrupts ..........................................................................................................
RTC Registers ..............................................................................................................
RTCINTEN Register Field Descriptions .................................................................................
RTCUPDATE Register Field Descriptions ..............................................................................
RTCMIL Register Field Descriptions.....................................................................................
RTCMILA Register Field Descriptions ...................................................................................
RTCSEC Register Field Descriptions....................................................................................
RTCSECA Register Field Descriptions ..................................................................................
RTCMIN Register Field Descriptions ....................................................................................
RTCMINA Register Field Descriptions ..................................................................................
RTCHOUR Register Field Descriptions .................................................................................
RTCHOURA Register Field Descriptions ...............................................................................
RTCDAY Register Field Descriptions....................................................................................
RTCDAYA Register Field Descriptions ..................................................................................
RTCMONTH Register Field Descriptions ...............................................................................
RTCMONTHA Register Field Descriptions .............................................................................
RTCYEAR Register Field Descriptions ..................................................................................
RTCYEARA Register Field Descriptions ................................................................................
RTCINTFL Register Field Descriptions..................................................................................
RTCNOPWR Register Field Descriptions ...............................................................................
RTCINTREG Register Field Descriptions ...............................................................................
RTCDRIFT Register Field Descriptions .................................................................................
RTCOSC Register Field Descriptions ...................................................................................
RTCPMGT Register Field Descriptions .................................................................................
RTCSCR1 Register 1 Field Descriptions................................................................................
RTCSCR2 Register Field Descriptions ..................................................................................
RTCSCR3 Register Field Descriptions ..................................................................................
RTCSCR4 Register Field Descriptions ..................................................................................
List of Tables
13
14
17
18
20
20
21
21
22
22
23
23
24
24
25
25
26
26
27
27
28
29
30
31
31
32
33
33
34
34
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Preface
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Read This First
About This Manual
This document describes real-time clock (RTC) on the TMS320C5515/14/05/04 digital signal processor
(DSP).
Notational Conventions
This document uses the following conventions.
• Hexadecimal numbers are shown with the suffix h. For example, the following number is 40
hexadecimal (decimal 64): 40h.
• Registers in this document are shown in figures and described in tables.
– Each register figure shows a rectangle divided into fields that represent the fields of the register.
Each field is labeled with its bit name, its beginning and ending bit numbers above, and its
read/write properties below. A legend explains the notation used for the properties.
– Reserved bits in a register figure designate a bit that is used for future device expansion.
Related Documentation From Texas Instruments
The following documents describe the TMS320C5515/14/05/04 digital signal processor (DSP). Copies of
these documents are available on the internet at http://www.ti.com.
SWPU073 — TMS320C55x 3.0 CPU Reference Guide. This manual describes the architecture,
registers, and operation of the fixed-point TMS320C55x digital signal processor (DSP) CPU.
SPRU652 — TMS320C55x DSP CPU Programmer’s Reference Supplement. This document describes
functional exceptions to the CPU behavior.
SPRUFO1A — TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) Inter-Integrated
Circuit (I2C) Peripheral User's Guide. This document describes the inter-integrated circuit (I2C)
peripheral in the TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The
I2C peripheral provides an interface between the device and other devices compliant with Phillips
Semiconductors Inter-IC bus (I2C-bus) specification version 2.1 and connected by way of an I2Cbus. This document assumes the reader is familiar with the I2C-bus specification.
SPRUFO2 — TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) Timer/Watchdog
Timer User's Guide. This document provides an overview of the three 32-bit timers in the
TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The 32-bit timers of
the device are software programmable timers that can be configured as general-purpose (GP)
timers. Timer 2 can be configured as a GP, a Watchdog (WD), or both simultaneously.
SPRUFO3 — TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) Serial Peripheral
Interface (SPI) User's Guide. This document describes the serial peripheral interface (SPI) in the
TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The SPI is a highspeed synchronous serial input/output port that allows a serial bit stream of programmed length (1
to 32 bits) to be shifted into and out of the device at a programmed bit-transfer rate. The SPI
supports multi-chip operation of up to four SPI slave devices. The SPI can operate as a master
device only.
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Related Documentation From Texas Instruments
www.ti.com
SPRUFO4 — TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) General-Purpose
Input/Output (GPIO) User's Guide. This document describes the general-purpose input/output
(GPIO) on the TMS320C5515/14/05/04/VC05/VC04 digital signal processor (DSP) devices. The
GPIO peripheral provides dedicated general-purpose pins that can be configured as either inputs or
outputs. When configured as an input, you can detect the state of an internal register. When
configured as an output you can write to an internal register to control the state driven on the output
pin.
SPRUFO5 — TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) Universal
Asynchronous Receiver/Transmitter (UART) User's Guide. This document describes the
universal asynchronous receiver/transmitter (UART) peripheral in the
TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The UART performs
serial-to-parallel conversions on data received from a peripheral device and parallel-to-serial
conversion on data received from the CPU.
SPRUFP1 — TMS320C5515/05/VC05 Digital Signal Processor (DSP) Successive Approximation
(SAR) Analog to Digital Converter (ADC) User's Guide. This document provides an overview of
the Successive Approximation (SAR) Analog to Digital Converter (ADC) on the
TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The SAR is a 10-bit
ADC using a switched capacitor architecture which converts an analog input signal to a digital
value.
SPRUFP3 — TMS320C5515/05/VC05 Digital Signal Processor (DSP) Liquid Crystal Display
Controller (LCDC) User's Guide. This document describes the liquid crystal display controller
(LCDC) in the TMS320C5515/14/05/04/VC05/VC04 Digital Signal Processor (DSP) devices. The
LCD controller includes a LCD Interface Display Driver (LIDD) controller.
SPRUFT2— TMS320C5515/14/05/04 DSP Direct Memory Access (DMA) Controller User's Guide This
document describes the features and operation of the DMA controller that is available on the
TMS320C5515/14/05/04 Digital Signal Processor (DSP) devices. The DMA controller is used to
move data among internal memory, external memory, and peripherals without intervention from the
CPU and in the background of CPU operation.
SPRUGU6— TMS320C5515/14/05/04 DSP External Memory Interface (EMIF) User's Guide. This
document describes the operation of the external memory interface (EMIF) in the
TMS320C5515/14/05/04 Digital Signal Processor (DSP) devices. The purpose of the EMIF is to
provide a means to connect to a variety of external devices.
SPRUFO6— TMS320C5515/14/05/04/VC05/VC04 DSP Multimedia Card (MMC)/Secure Digital (SD)
Card Controller This document describes the Multimedia Card (MMC)/Secure Digital (SD) Card
Controller on the TMS320C5515/14/05/04 Digital Signal Processor (DSP) devices. The multimedia
card (MMC)/secure digital (SD) card is used in a number of applications to provide removable data
storage. The MMC/SD card controller provides an interface to external MMC and SD cards.
SPRUFX2— TMS320C5515/14/05/04 Digital Signal Processor (DSP) Real-Time Clock (RTC) User's
Guide.This document describes the operation of the Real-Time Clock (RTC) module in the
TMS320C5515/14/05/04 Digital Signal Processor (DSP) devices. The RTC also has the capability
to wake-up the power management and apply power to the rest of the device through an alarm,
periodic interrupt, or external WAKEUP signal.
SPRUFX4— TMS320C5515/14/05/04 Digital Signal Processor (DSP) Inter-IC Sound (I2S) Bus User's
Guide. This document describes the features and operation of Inter-IC Sound (I2S) Bus in the
TMS320C5515/14/05/04 Digital Signal Processor (DSP) devices. This peripheral allows serial
transfer of full duplex streaming data, usually streaming audio, between DSP and an external I2S
peripheral device such as an audio codec.
SPRUFX5— TMS320C5515 DSP System User's Guide. This document describes various aspects of the
TMS320C5515 digital signal processor (DSP) including: system memory, device clocking options
and operation of the DSP clock generator, power management features, interrupts, and system
control.
6
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Related Documentation From Texas Instruments
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SPRUGH5— TMS320C5505 DSP System User's Guide. This document describes various aspects of
the TMS320C5505 digital signal processor (DSP) including: system memory, device clocking
options and operation of the DSP clock generator, power management features, interrupts, and
system control.
SPRUFX6— TMS320C5514 DSP System User's Guide. This document describes various aspects of the
TMS320C5514 digital signal processor (DSP) including: system memory, device clocking options
and operation of the DSP clock generator, power management features, interrupts, and system
control.
SPRUGH6— TMS320C5504 DSP System User's Guide.This document describes various aspects of the
TMS320C5504 digital signal processor (DSP) including: system memory, device clocking options
and operation of the DSP clock generator, power management features, interrupts, and system
control.
SPRUGH9— TMS320C5515 DSP Universal Serial Bus 2.0 (USB) Controller User's Guide This
document describes the universal serial bus 2.0 (USB) in the TMS320C5515 Digital Signal
Processor (DSP) devices. The USB controller supports data throughput rates up to 480 Mbps. It
provides a mechanism for data transfer between USB devices.
SPRABB6— FFT Implementation on the TMS320VC5505, TMS320C5505, and TMS320C5515 DSPs
This document describes FFT computation on the TMS320VC5505 and TMS320C5505/15 DSPs
devices.
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7
Chapter 1
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Real-Time Clock (RTC)
Topic
1.1
1.2
1.3
8
...........................................................................................................................
Page
Introduction ........................................................................................................ 9
Peripheral Architecture ....................................................................................... 10
Registers........................................................................................................... 18
Real-Time Clock (RTC)
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1.1
Introduction
The following sections describe the features and operation of the real-time clock (RTC) on the digital
signal processor (DSP).
1.1.1 Purpose of the Peripheral
The device includes a real time clock (RTC) that provides a time reference to an application executing on
the DSP.
The RTC has its own crystal input, clock domain, and core and I/O power supplies. The separate clock
domain allows the RTC to run while the rest of the device is clock gated. All RTC registers are preserved
and the counter continues to operate when the host CPU is clock gated. The RTC has the capability to
wake-up the rest of the device through an alarm interrupt, periodic interrupt, or external WAKEUP signal.
NOTE: The RTC Core (CVDDRTC) must be powered using an external power source if the RTC is not
used.
1.1.2
Features
The real-time clock (RTC) provides the following features:
• RTC-only mode
• 100-year calendar up to year 2099
• Counts milliseconds, seconds, minutes, hours, and date (including day, month, and year with leap year
compensation)
• Millisecond time correction
• Binary-coded-decimal (BCD) representation of time, calendar, and alarm
• 24-hour clock mode
• Alarm interrupt for specific millisecond, second, minute, hour, day, month, and year
• Periodic interrupt: every millisecond, second, minute, hour, or day
• Single interrupt to the DSP CPU
• 32.768kHz oscillator with frequency calibration
• Bidirectional I/O pin that can be set up as:
– Input for an external device to wake up the DSP
– Output to wake up an external device
The current date and time is tracked in a set of counter registers that update once per millisecond. The
time is represented in 24-hour mode. For information on how to set the time and date, see Section 1.2.4.
Alarms can be set to interrupt the DSP CPU at a particular time, or at periodic time intervals, such as once
per minute or once per day. For information on how to set and use alarms, see Section 1.2.5.
The clock reference for the RTC is an external 32.768kHz crystal (connected between signals RTC_XI
and RTC_XO). The RTC also has separate core and I/O power supplies that are isolated from the rest of
the DSP.
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1.1.3 Functional Block Diagram
Figure 1-1 shows a block diagram of the RTC.
Figure 1-1. Block Diagram
Real Time Clock
RTC_XI
Oscillator
RTC_XO
Time/ Calendar /Alarm
Counters
Periodic Interrupt
Alarm Interrupt
RTC IRQ
to CPU
Interrupt
Control
WAKEUP
WU_DOUT
Write
Buffer
Read
Buffer
Control and Status
Registers
WU_DIR
Peripheral Bus
1.2
Peripheral Architecture
This section describes the Real-Time Clock (RTC) peripheral.
NOTE:
If the WAKEUP pin is used to wake up the device, DVDDRTC and CVDDRTC must be powered. If
the RTC is not used DVDDRTC can be tied to ground (VSS), but CVDDRTC must be powered by an
external power source. In addition, the RTC_XI pin must be tied to CVDDRTC and the RTC_XO
pin must be tied to VSS. If the RTC_XI and RTC_XO pins are tied off, then the RTC registers
are inaccessible.
1.2.1 Clock Control
The RTC oscillator is driven by an external 32.768 KHz crystal connected between RTC_XI and RTC_XO.
1.2.2 Signal Descriptions
As shown in Figure 1-1, the WAKEUP pin is a bidirectional pin that can be used as an input to wake up
the DSP clock domains or it can be used as an open-drain output to wake up an external device. At
power-up the WAKEUP pin is configured as an input. This signal can be used to trigger the RTC interrupt
to the CPU and to wake-up gated clocks regardless of whether the clocks were gated by the master clock
gate or whether they were gated by the DSP's idle instruction.
A high pulse for a minimum of one RTC clock period (30.5 μs) to the WAKEUP pin will trigger the RTC
interrupt when:
• The WAKEUP pin is configured as an input (RTCPMGT:WU_DIR = 0)
• The RTC interrupt is enabled (RTCINTEN:RTCINTEN = 1)
• The External Event Interrupt in RTCINTREG is enabled (RTCINTREG:EXTINTEN = 1)
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In addition, when WAKEUP is high, the Master Clock Gater for the whole digital core is forced into the ungated state (clocks on). Note that the interrupt generation is edge sensitive while the clocks on condition is
level sensitive. Please see Section 1.2.6 for Interrupt support.
1.2.3 RTC-Only Mode
RTC-only mode allows all supplies except LDOI, DVDDRTC and CVDDRTC to be powered down. In this mode,
the RTC counter continues to operate. The RTC has the capability to wake up the device from idle states,
or completely power down the CPU, via alarms, periodic interrupts, or an external WAKEUP input. The
RTC will reboot after waking up from the CPU powering down.
In addition, the RTC is able to output an alarm or periodic interrupt on the WAKEUP pin to cause external
power management to re-enable power to the DSP core and I/O.
1.2.4 Using the Real-Time Clock Time and Calendar Registers
The current time and date are maintained in the RTC time and calendar registers. Information about how
to use these registers is in the sections that follow.
1.2.4.1
Time/Calendar Data Format
The time and calendar data in the RTC is stored as binary-coded decimal (BCD) format. In BCD format,
the decimal numbers 0 through 9 are encoded with their binary equivalent. Although most of the
time/calendar registers have 4 bits assigned to each BCD digit, some of the register fields are shorter
since the range of valid numbers may be limited. For example, only 3 bits are required to represent the
first digit (most significant digit) of the “seconds” because only 0 through 5 are required.
The summary of the time/calendar registers is shown in Table 1-1. The alarm registers are interleaved
with the time/calendar registers and are not shown in this table. The alarm registers are shown in Table 12. A complete description all RTC registers is available in Section 1.3.
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Table 1-1. Time/Calendar Registers
Address (Hex)
•
•
•
•
•
•
•
1.2.4.2
Name
Function
1904h
RTCMIL
Milliseconds
Decimal Range
BCD Format
0-1023
1908h
RTCSEC
0000-1023
Seconds
0-59
00-59
190Ch
1910h
RTCMIN
Minutes
0-59
00-59
RTCHOUR
Hours (24)
0-23
00-23
1914h
RTCDAY
Days
1-31
01-31
1918h
RTCMONTH
Months (January = 01)
1-12
01-12
191Ch
RTCYEAR
Years
0-99
00-99
The RTC Milliseconds Register (RTCMIL) stores the milliseconds value of the current time. After the
milliseconds count reaches 1023 then the seconds register is updated by one. The reason for the
rollover occurring at 1024, rather than 1000, is due to the crystal's oscillation frequency being a power
of two, 32.768kHz. 32768 / 1024 = 32 clocks per 'millisecond'. Thus, calling this register a
'milliseconds' register is a bit of a misnomer. The milliseconds digit 3 is 1 bit and the milliseconds digits
2:0 are 4 bits; digits 3:0 are encoded BCD values 0000 (0b 0000b 0000b 0000b) through 1023 (1b
0000b 0010b 0011b).
The RTC Seconds Register (RTCSEC) stores the seconds value of the current time. The seconds digit
1 is 3 bits and the seconds digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 00 (000b 0000b)
through 59 (101b 1001b).
The RTC Minutes Register (RTCMIN) stores the minutes value of the current time. The minutes digit 1
is 3 bits and the minutes digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 00 (000b 0000b)
through 59 (101b 1001b).
The RTC Hours Register (RTCHOUR) stores the hours value of the current time. The hours digit 1 is 2
bits and the hours digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 01 (00b 0001b) through 23
(10b 0011b).
The RTC Days Register (RTCDAY) stores the day of the month for the current date. The days digit 1 is
2 bits and the days digit 0 is 4 bits; digits 1 and 0 are encoded BCD 01 (00b 0001b) through 31 (11b
0001b).
The RTC Months Register (RTCMONTH) stores the month for the current date. The months digit 1 is 1
bit and the months digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 01 (0b 0000b) through 12
(1b 0010b).
The RTC Years Register (RTCYEAR) stores the year for the current date. The years digit 1 is 4 bits
and the years digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 00 (0000b 0000b) through 99
(1001b 1001b).
Setting the Time/Calendar Register
The time/calendar registers are set or initialized by writing to the appropriate register bytes. To set date
and time, unlock the RTC registers and write all the time and date registers. When written to, the data is
stored to a buffer. Next, set the TIMEUPDT bit in the RTC Update Register (RTCUPDATE). Setting this bit
causes the time/calendar values in the buffer to be loaded into the RTC simultaneously. All values should
be encoded as BCD values.
1.2.4.3
Reading the Time/Calendar Registers
The time/calendar registers are updated every millisecond as the time changes. To get the most accurate
time reading you should start with reading the Millisecond register (RTCMIL) and then the Second register
(RTCSEC) followed by the remaining time/calendar register values (RTCMIN, RTCHOUR, RTCDAY,
RTCMONTH, and RTCYEAR). Read the RTCMIL again and compare to the previous value. If both values
are the same, an RTC update did not occur while the other registers were being read and all the values
read represent the current time. If the Milliseconds have changed, this indicates that and RTC update
occurred while the registers were being read and the process should be repeated. Results are
unpredictable if values are written out of the register's normal range.
12
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1.2.5 Using the Real-Time Clock Time and Calendar Alarms
Alarms can be configured to interrupt the CPU at a specific time, that is, at specific values for the
following:
• Milliseconds
• Seconds
• Minutes
• Hours
• Days of the month
• Months
• On specific Years
The time/calendar alarm registers control the setting of alarms. Information about how to use these
registers can be found in the following sections. The alarms can be configured to generate an interrupt to
the CPU or to wake-up the clocks. The operation of the alarm interrupt is described in Section 1.2.6.4.
1.2.5.1
Time/Calendar Alarm Data Format
The time and calendar alarm data in the RTC is stored as binary-coded decimal (BCD) format. In BCD
format, the decimal numbers 0 through 9 are encoded with their binary equivalent. Although most of the
time/calendar alarm registers have 4 bits assigned to each BCD digit, some of the register field lengths
may differ to accommodate the desired function.
The summary of the time/calendar alarm registers is shown in Table 1-2. The time/calendar registers are
interleaved with the alarm registers and are not shown in this table. The time/calendar registers are shown
in Table 1-1. A complete description of all RTC registers is available in Section 1.3.
Table 1-2. Time and Calendar Alarm Data
Address (Hex)
Name
Function
1905h
RTCMILA
Milliseconds alarm
Decimal Range
BCD Format
0-1023
1909h
RTCSECA
0000-1023
Seconds alarm
0-59
190Dh
00-59
RTCMINA
Minutes alarm
0-59
00-59
1911h
RTCHOURA
Hours (24) alarm
0-23
00-23
1915h
RTCDAYA
Days alarm
1-31
01-31
1919h
RTCMONTHA
Months (January = 01) alarm
1-12
01-12
191Dh
RTCYEARA
Years alarm
0-99
00-99
The RTC Milliseconds Alarm Register (RTCMILA) stores the milliseconds value of the desired alarm. The
milliseconds alarm digit 3 is 1 bit and the milliseconds alarm digits 2:0 are 4; digits 3:0 are encoded BCD
values 0000 (0b 0000b 0000b 0000b) through 1023 (1b 0000b 0010b 0011b). Values outside of the
decimal range of 0 – 1023 will cause the alarm to never occur.
The RTC Seconds Alarm Register (RTCSECA) stores the seconds value of the desired alarm. The
seconds alarm digit 1 is 3 bits and the seconds alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD
values 00 (000b 0000b) through 59 (101b 1001b). Values outside of the decimal range of 0 - 59 will cause
the alarm to never occur.
The RTC Minutes Alarm Register (RTCMINA) stores the minute value of the desired alarm. The minutes
alarm digit 1 is 3 bits and the minutes alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 00
(000b 0000b) through 59 (101b 1001b). Values outside of the decimal range of 0 - 59 will cause the alarm
to never occur.
The RTC Hours Alarm Register (RTCHOURA) stores the hour value of the desired alarm. The hours
alarm digit 1 is 2 bits and the hours alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 01 (00b
0001b) through 23 (10b 0011b). Values outside of the decimal range of 1 - 23 will cause the alarm to
never occur.
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The RTC Days Alarm Register (RTCDAYA) stores the day of the month value of the desired alarm. The
days alarm digit 1 is 2 bits and the days alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD 01 (00b
0001b) through 31 (11b 0001b). Values outside of the decimal range of 1 - 31 will cause the alarm to
never occur.
The RTC Months Alarm Register (RTCMONTHA) stores the month of the year value of the desired alarm.
The months alarm digit 1 is 1 bit and the months alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD
values 01 (0b 0000b) through 12 (1b 0010b). Values outsides the range 1 - 12 will cause the alarm to
never occur.
The RTC Years Alarm Register (RTCYEARA) stores the year value of the desired alarm. The years alarm
digit 1 is 4 bits and the years alarm digit 0 is 4 bits; digits 1 and 0 are encoded BCD values 00 (0000b
0000b) through 99 (1001b 1001b). Values outsides the range 0 - 99 will cause the alarm to never occur.
1.2.5.2
Setting and Reading the Time/Calendar Alarm Registers
The time/calendar alarm registers are set or initialized by writing to the appropriate register bytes. To set
date and time, write all the time and date registers. Then set the ALARMUPDT bit in the RTC Update
Register (RTCUPDATE). This will simultaneously copy all the alarm register settings in one RTC cycle.
Time/calendar alarm registers can be read at any time and are not updated by the RTC.
1.2.5.3
Examples of Time/Calendar Alarm Settings
Some examples of various alarm settings are shown in Table 1-3. A complete description of the RTC
registers and their functions is provided in Section 1.3.
Table 1-3. Time/Calendar Alarm Settings
RTCYEARA
RTCMONTHA
RTCDAYA
RTCHOURA
RTCMINA
RTCSECA
RTCMILA
May 7, 2010 @ 3:19:46
AM
Alarm Occurs…
10h
5h
7h
3h
19h
46h
0h
Dec 22, 2099 @ 5:50:15
and 300ms PM
99h
12h
22h
17h
50h
15h
300h
1.2.6 Real-Time Clock Interrupt Requests
The RTC provides the ability to interrupt the CPU based on three events: a periodic interrupt, an alarm
interrupt, or an external "Wakeup" interrupt. Although three interrupt sources are available, the RTC
makes a single interrupt request to the CPU. Specific information about using each of the interrupt types is
in the sections that follow.
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1.2.6.1
Interrupt Enable
The RTC has two registers for enabling interrupts. The RTC Interrupt Enable (RTCINTEN) enables the
RTC interrupt to the CPU. This bit allows any interrupt that is triggered in the RTC to be sent to the CPU.
The second register is the RTC Interrupt Register (RTSINTREG) is used to enable the different interrupt
events that can be passed to the CPU. These include the following:
• Alarm Interrupt
• External “wakeup” Interrupt
• Periodic Day Interrupt
• Periodic Hour Interrupt
• Periodic Minute Interrupt
• Periodic Second Interrupt
• Periodic Millisecond Interrupt
NOTE: To use the external wakeup interrupt, you must set the WU_DIR bit in the RTCPMGT
register to 0.
When an RTC interrupt is generated, the RTC’s interrupt is directed to two places (see Figure 1-2).
1. System Clock Wakeup Logic: the interrupt will cause the Master Clock Gater to enable the Master
Clock.
2. The RTC interrupt can be directed to the CPU if RTCINTEN = 1. The CPU's RTC interrupt must be
unmasked for the CPU to respond to the interrupt.
• If the CPU is idled, the interrupt will cause the CPU to exit idle. If interrupts are globally enabled,
the CPU will execute the RTC ISR.
• If the CPU is not idled and interrupts are globally enabled, the CPU will execute the RTC ISR.
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Figure 1-2. RTC Interrupt and Wakeup Logic
Master CLK gate
Wake
Up
WU_DOUT
WU_ DIR
EXTINTEN
DAYINTEN
day_evt
HOURINTEN
RTCINTEN
hour_evt
MININTEN
Time
Registers
Periodic
Event
Detection
RTC
Interrupt
Flags
DSP INT
min_evt
SECINTEN
sec_evt
MSINTEN
ms_evt
ALARMINTEN
Alarm
Registers
1.2.6.2
alarm_evt
Alarm
Event
Detection
Interrupt Flag Bits
When the interrupts are enabled in Section 1.2.6.1 and the event occurs, the equivalent flag is set in the
RTC Interrupt Flag Register (RTCINTFL). See Section 1.3 for complete details of the RTC registers. The
flagged event is cleared when the programmer writes a "1" to the flag bit.
There is also an RTC Lost Power Register (RTCNOPWR). If this flag is set the RTC has lost power and
requires a software reset. NOTE: at least 3 RTC clock cycles must elapse after power-up in order to read
valid data since the synchronization logic between the CPU and RTC consumes 3 RTC clock cycles.
If the RTC Interrupt enable bit is set and any of the active events occur then an RTC interrupt is sent to
the CPU. The RTC interrupt is asserted as long as at least one of the interrupt flag bits are set. When an
interrupt occurs from the RTC, the source of the interrupt can be determined by reading the flag bits in
RTCINTFL.
1.2.6.3
Periodic Interrupt Request
Periodic Interrupts cause the RTC to make an interrupt request to the CPU periodically. The periodicity
can be every millisecond, every second, every minute, hourly, or daily. The periodic interrupt rate is
selected using the RTC Interrupts Register (RTCINTREG), see Table 1-4. Writing a 1 to these bits
enables the periodic interrupt. Writing a 0 disables the interrupt. Once the interrupt occurs it will remain
active until the corresponding flag bit in the RTC Status Register is cleared.
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NOTE: The interrupt occurs whenever that particular time value is incremented.
Table 1-4. Periodic Interrupts
RTCINTREG bits
Periodic Interrupt Rate
Bit 0
Every Millisecond
Bit 1
Every Second
Bit 2
Every Minute
Bit 3
Every Hour
Bit 4
Every Day
To use the RTC Periodic interrupt:
• Select the desired interrupt period by enabling the proper interrupt in the RTCINTREG
• Enable the RTC interrupt to the CPU by setting bit 0 of RTCINTEN
When the periodic interrupt occurs, the corresponding interrupt flag will be set in the RTC Interrupt Flag
(RTCINTFL) register and the interrupt is sent to the CPU.
1.2.6.4
Alarm Interrupt Request
The RTC alarm interrupt can be used to generate an interrupt to the CPU at a specific time. The alarm
interrupt occurs when the alarm time programmed in the RTC alarm registers match the current time. For
information about programming an alarm time, see Section 1.2.5.
To
•
•
•
use the RTC alarm interrupt:
Select the desired alarm time by configuring the RTC alarm registers.
Enable the RTC alarm interrupt by setting bit 15 of the RTCINTREG.
Enable the RTC interrupt to the CPU by setting bit 0 of RTCINTEN
When the alarm interrupt occurs, the Alarm Flag (bit 15) in the RTCINTFL register will be set and the RTC
interrupt is sent to the CPU.
1.2.6.5
WAKEUP Interrupt Request
The external WAKEUP signal or RTC alarm trigger sends a WAKEUP event to the System Clock Wakeup
Logic. This asynchronously clears the clock gate which gates the Master Clock and enables the Master
Clock. When the DSP wakes up due to an RTC alarm, periodic interrupt, or by the external WAKEUP
signal, the DSP latches the RTC interrupt. Because there is only one interrupt line for the RTC, the user
must look at the RTC status register to determine which RTC event caused the wake-up.
1.2.7 Reset Considerations
The RTC can be reset by the RTCRESET bit located in the RTC oscillator register (RTCOSC). The RTC
can also be reset by an internal POR circuit that monitors VDD_RTC. Neither the RESETN pin nor the
DSP's POR can reset the RTC.
1.2.7.1
Software Reset Considerations
The DSP can cause a software reset of the RTC when the RTCRESET bit is set to 1. When this occurs,
all RTC registers are reset to the default settings. The RTC will not be reset when the RESETN pin goes
low. After a RTC software reset, do not access any RTC register for three 32.768kHz clock cycles after
setting the software reset bit.
1.2.7.2
Hardware Reset Considerations
The RTC has a hardware reset that is tied to a POR circuit that monitors the VDD_RTC. The RTC is not
reset with the RESETN pin or the DSP's POR.
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1.3.1 Overview
This section describes the memory-mapped registers for the Real Time Clock (RTC).
Control of the RTC is maintained through a set of I/O memory mapped registers. The first two registers,
RTCINTEN and RTCUPDATE, are located in the DSP core power domain, while the remaining registers in
Table 5 are located in the RTC power domain.
Writes to registers in the RTC power domain are synchronized to the RTC 32.768-kHz clock and can
therefore take many CPU clock cycles to complete. The CPU clock must run at least three-times faster
than the RTC, and writes to registers in the RTC domain will not be evident for up to two 32.768kHz clock
cycles. If the RTC oscillator is disabled (RTC_XI and RTC_XO pins tied off), no RTC register in the RTC
power domain can be written.
1.3.2 RTC Registers
This section describes the memory-mapped registers for the Real Time Clock (RTC).
Control of the RTC is maintained through a set of I/O memory mapped registers. The first two registers,
RTCINTEN and RTCUPDATE, are located in the DSP core power domain, while the remaining registers in
Table 5 are located in the RTC power domain.
Writes to registers in the RTC power domain are synchronized to the RTC 32.768-kHz clock and can
therefore take many CPU clock cycles to complete. The CPU clock must run at least three-times faster
than the RTC, and writes to registers in the RTC domain will not be evident for up to two 32.768kHz clock
cycles. If the RTC oscillator is disabled (RTC_XI and RTC_XO pins tied off), no RTC register in the RTC
power domain can be written.
Table 1-5. RTC Registers
18
Offset
Acronym
Register Name
1900h
RTCINTEN
RTC Interrupt Enable Register
Section 1.3.2.1
1901h
RTCUPDATE
RTC Update Register
Section 1.3.2.2
1904h
RTCMIL
Milliseconds Register
Section 1.3.2.3
1905h
RTCMILA
Milliseconds Alarm Register
Section 1.3.2.4
1908h
RTCSEC
Seconds Register
Section 1.3.2.5
1909h
RTCSECA
Seconds Alarm Register
Section 1.3.2.6
190Ch
RTCMIN
Minutes Register
Section 1.3.2.7
190Dh
RTCMINA
Minutes Alarm Register
Section 1.3.2.8
1910h
RTCHOUR
Hours Register
Section 1.3.2.9
1911h
RTCHOURA
Hours Alarm Register
Section 1.3.2.10
1914h
RTCDAY
Days Register
Section 1.3.2.11
1915h
RTCDAYA
Days Alarm Register
Section 1.3.2.12
1918h
RTCMONTH
Months Register
Section 1.3.2.13
1919h
RTCMONTHA
Months Alarm Register
Section 1.3.2.14
191Ch
RTCYEAR
Years Register
Section 1.3.2.15
191Dh
RTCYEARA
Years Alarm Register
Section 1.3.2.16
1920h
RTCINTFL
RTC Interrupt Flag Register
Section 1.3.2.17
1921h
RTCNOPWR
RTC Lost Power Status Register
Section 1.3.2.18
1924h
RTCINTREG
RTC Interrupt Register
Section 1.3.2.19
1928h
RTCDRIFT
RTC Compensation Register
Section 1.3.2.20
192Ch
RTCOSC
RTC Oscillator Register
Section 1.3.2.21
1930h
RTCPMGT
RTC Power Management Register
Section 1.3.2.22
1960h
RTCSCR1
RTC LSW Scratch Register 1
Section 1.3.2.23
1961h
RTCSCR2
RTC MSW Scratch Register 2
Section 1.3.2.24
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Table 1-5. RTC Registers (continued)
Offset
Acronym
Register Name
1964h
RTCSCR3
RTC LSW Scratch Register 3
Section 1.3.2.25
1965h
RTCSCR4
RTC MSW Scratch Register 4
Section 1.3.2.26
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RTCINTEN Register
The RTC interrupt enable register (RTCINTEN) is shown in Figure 1-3 and described in Table 1-6.
Figure 1-3. RTCINTEN Register
15
1
0
Reserved
RTCINTEN
R-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-6. RTCINTEN Register Field Descriptions
Bit
Field
15-1
Type
Reserved
0
RTCINTEN
1.3.2.2
Reset Description
R
0
Reserved.
R/W
0
RTC interrupt enable.
0 = RTC interrupt is disabled.
1 = RTC interrupt is enabled.
RTCUPDATE Register
The RTC update register (RTCUPDATE) is shown in Figure 1-4 and described in Table 1-7.
Figure 1-4. RTCUPDATE Register
15
14
13
TIMEUPDT
ALARMUPDT
Reserved
0
RW-0
RW-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-7. RTCUPDATE Register Field Descriptions
Bit
Field
15
TIMEUPDT
RW
0
Initiates the Time updates.
0 = RTC time registers updated.
1 = Initiates the transfar of the time registers from the DSP to the RTC
14
ALARMUPDT
RW
0
Initiates the alarm updates.
0 = RTC alarm registers updated.
1 = Initiate update of the alarm registers.
R
0
Reserved.
13-0
20
Reserved
Real-Time Clock (RTC)
Type
Reset Description
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1.3.2.3
RTCMIL Register
The milliseconds register (RTCMIL) is shown in Figure 1-5 and described in Table 1-8.
Figure 1-5. RTCMIL Register
15
13
12
11
8
7
4
3
0
Reserved
MS3
MS2
MS1
MS0
R-0
RW-0
RW-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-8. RTCMIL Register Field Descriptions
Bit
Field
Type
15-13 Reserved
Reset Description
R
0
Reserved.
12
MS3
R/W
0
Digit 3 of Milliseconds in BCD format.
0 = Digit 3 of MS is 0.
1 = Digit 3 of MS is 1.
11-8
MS2
R/W
0
Digit 2 of Milliseconds in BCD format, value 0 to 9.
7-4
MS1
R/W
0
Digit 1 of Milliseconds in BCD format, value 0 to 9
3-0
MS0
R/W
0
Digit 0 of Milliseconds in BCD format, value 0 to 9
1.3.2.4
RTCMILA Register
The milliseconds alarm register (RTCMILA) is shown in Figure 1-6 and described in Table 1-9.
Figure 1-6. RTCMILA Register (RTCMILA)
15
13
12
11
8
7
4
3
0
Reserved
MSA3
MSA2
MSA1
MSA0
R-0
RW-0
RW-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-9. RTCMILA Register Field Descriptions
Bit
Field
15-13 Reserved
Type
Reset Description
R
0
Reserved.
12
MSA3
RW
0
Digit 3 of Millisecond alarm in BCD format.
0 = Digit 3 of MS Alarm is 0.
1 = Digit 3 of MS Alarm is 1.
11-8
MSA2
RW
0
Digit 2 of Millisecond alarm in BCD format, value 0 to 9
7-4
MSA1
RW
0
Digit 1 of Millisecond alarm in BCD format, value 0 to 9
3-0
MSA0
RW
0
Digit 0 of Millisecond alarm in BCD format, value 0 to 9
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RTCSEC Register
The seconds register (RTCSEC) is shown in Figure 1-7 and described in Table 1-10.
Figure 1-7. RTCSEC Register
15
7
6
4
3
0
Reserved
SEC1
SEC0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-10. RTCSEC Register Field Descriptions
Bit
Field
Type
Reset Description
15-7
Reserved
R
0
Reserved.
6-4
SEC1
RW
0
Digit 1 of Seconds in BCD format, value 0 to 5
3-0
SEC0
RW
0
Digit 0 of Seconds in BCD format, value 0 to 9
1.3.2.6
RTCSECA Register
The seconds alarm register (RTCSECA) is shown in Figure 1-8 and described in Table 1-11.
Figure 1-8. RTCSECA Register
15
7
6
4
3
0
Reserved
SECA1
SECA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-11. RTCSECA Register Field Descriptions
Bit
Field
Type
Reset Description
15-7
Reserved
R
0
Reserved.
6-4
SECA1
R/W
0
Digit 1 of Seconds Alarm in BCD format, value 0 to 5
3-0
SECA0
R/W
0
Digit 0 of Seconds Alarm in BCD format, value 0 to 9
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1.3.2.7
RTCMIN Register
The minutes register (RTCMIN) is shown in Figure 1-9 and described in Table 1-12.
Figure 1-9. RTCMIN Register
15
7
6
4
3
0
Reserved
MIN1
MIN0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-12. RTCMIN Register Field Descriptions
Bit
Field
Type
Reset Description
15-7
Reserved
R
0
Reserved.
6-4
MIN1
R/W
0
Digit 1 of Minutes in BCD format, value 0 to 5
3-0
MIN0
R/W
0
Digit 0 of Minutes in BCD format, value 0 to 9
1.3.2.8
RTCMINA Register
The minutes alarm register (RTCMINA) is shown in Figure 1-10 and described in Table 1-13.
Figure 1-10. RTCMINA Register
15
7
6
4
3
0
Reserved
MINA1
MINA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-13. RTCMINA Register Field Descriptions
Bit
Field
Type
Reset Description
15-7
Reserved
R
0
Reserved.
6-4
MINA1
R/W
0
Digit 1 of Minutes Alarm in BCD format, 0 to 5
3-0
MINA0
R/W
0
Digit 0 of Minutes Alarm in BCD format, 0 to 9
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RTCHOUR Register
The hours register (RTCHOUR) is shown in Figure 1-11 and described in Table 1-14.
Figure 1-11. RTCHOUR Register
15
6
5
4
3
0
Reserved
HOUR1
HOUR0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-14. RTCHOUR Register Field Descriptions
Bit
Field
Type
Reset Description
15-6
Reserved
R
0
Reserved.
5-4
HOUR1
R/W
0
Digit 1 of Hours in BCD format, value 0 to 2
3-0
HOUR0
R/W
0
Digit 0 of Hours in BCD format, value 0 to 9
1.3.2.10 RTCHOURA Register
The hours alarm register (RTCHOURA) is shown in Figure 1-12 and described in Table 1-15.
Figure 1-12. RTCHOURA Register
15
6
5
4
3
0
Reserved
HOURA1
HOURA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-15. RTCHOURA Register Field Descriptions
Bit
Field
Type
Reset Description
15-6
Reserved
R
0
Reserved.
5-4
HOURA1
R/W
0
Digit 1 of Hours Alarm in BCD format, value 0 to 2
3-0
HOURA0
R/W
0
Digit 0 of Hours Alarm in BCD format, value 0 to 9
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1.3.2.11 RTCDAY Register
The days register (RTCDAY) is shown in Figure 1-13 and described in Table 1-16.
Figure 1-13. RTCDAY Register
15
6
5
4
3
0
Reserved
DAY1
DAY0
R-0
RW-0
RW-1
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-16. RTCDAY Register Field Descriptions
Bit
Field
Type
Reset Description
15-6
Reserved
R
0
Reserved.
5-4
DAY1
R/W
0
Digit 1 of Days in BCD format, 0 to 3
3-0
DAY0
R/W
1
Digit 0 of Days in BCD format, 0 to 9
1.3.2.12 RTCDAYA Register
The days alarm register (RTCDAYA) is shown in Figure 1-14 and described in Table 1-17.
Figure 1-14. RTCDAYA Register
15
6
5
4
3
0
Reserved
DAYA1
DAYA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-17. RTCDAYA Register Field Descriptions
Bit
Field
Type
Reset Description
15-6
Reserved
R
0
Reserved.
5-4
DAYA1
R/W
0
Digit 1 of Days Alarm in BCD format, 0 to 3
3-0
DAYA0
R/W
0
Digit 0 of Days Alarm in BCD format, value 0 to 9
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1.3.2.13 RTCMONTH Register
The months register (RTCMONTH) is shown in Figure 1-15 and described in Table 1-18.
Figure 1-15. RTCMONTH Register
15
5
4
3
0
Reserved
MONTH1
MONTH0
R-0
RW-0
RW-1
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-18. RTCMONTH Register Field Descriptions
Bit
Field
Type
Reset Description
15-5
Reserved
R
0
Reserved.
4
MONTH1
RW
0
Digit 1 of Months in BCD format, value 0 to 1.
3-0
MONTH0
RW
1
Digit 0 of Months in BCD format, value 0 to 9.
1.3.2.14 RTCMONTHA Register
The months alarm register (RTCMONTHA) is shown in Figure 1-16 and described in Table 1-19.
Figure 1-16. RTCMONTHA Register
15
5
4
3
0
Reserved
MONTHA1
MONTHA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-19. RTCMONTHA Register Field Descriptions
Bit
15-5
26
Field
Reserved
Type
Reset Description
R
0
Reserved.
4
MONTHA1
RW
0
Digit 1 of Months Alarm in BCD format, value 0 to 1.
3-0
MONTHA0
RW
0
Digit 0 of Months Alarm in BCD format, value 0 to 9.
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1.3.2.15 RTCYEAR Register
The years register (RTCYEAR) is shown in Figure 1-17 and described in Table 1-20.
Figure 1-17. RTCYEAR Register
15
8
7
4
3
0
Reserved
YEAR1
YEAR0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-20. RTCYEAR Register Field Descriptions
Bit
Field
Type
Reset Description
15-8
Reserved
R
0
Reserved.
7-4
YEAR1
RW
0
Digit 1 of Year in BCD format (20XX), value 0 to 9.
3-0
YEAR0
RW
0
Digit 0 of Year in BCD format (20XX), value 0 to 9.
1.3.2.16 RTCYEARA Register
The years alarm register (RTCYEARA) is shown in Figure 1-18 and described in Table 1-21.
Figure 1-18. RTCYEARA Register
15
8
7
4
3
0
Reserved
YEARA1
YEARA0
R-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-21. RTCYEARA Register Field Descriptions
Bit
Field
Type
Reset Description
15-8
Reserved
R
0
Reserved.
7-4
YEARA1
RW
0
Digit 1 of Year Alarm in BCD format (20XX), value 0 to 9.
3-0
YEARA0
RW
0
Digit 0 of Year Alarm in BCD format (20XX), value 0 to 9.
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1.3.2.17 RTCINTFL Register
The RTC interrupt flag register (RTCINTFL) is shown in Figure 1-19 and described in Table 1-22.
Figure 1-19. RTCINTFL Register
15
14
8
ALARMFL
Reserved
R/W-0
R-0
7
5
4
3
2
1
0
Reserved
6
EXTFL
DAYFL
HOURFL
MINFL
SECFL
MSFL
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-22. RTCINTFL Register Field Descriptions
Bit
Field
Type
15
ALARMFL
R/W
0
Flag indicating whether an Alarm interrupt has occurred.
0 = Alarm interrupt did not occur.
1 = Alarm interrupt occurred (write 1 to clear)
14-6
Reserved
R
0
Reserved.
28
Reset Description
5
EXTFL
R/W
0
Flag indicating whether an external event interrupt (WAKEUP pin) has occurred.
0 = External event interrupt did not occur
1= External event interrupt occurred (write 1 to clear).
4
DAYFL
R/W
0
Flag indicating whether a periodic Day interrupt has occurred.
0 = Periodic Day interrupt did not occur.
1 = Periodic Day interrupt occurred (write 1 to clear).
3
HOURFL
R/W
0
Flag indicating whether a periodic Hour event interrupt has occurred.
0 = Periodic Hour interrupt did not occur.
1 = Periodic Hour interrupt occurred (write 1 to clear).
2
MINFL
R/W
0
Flag indicating whether a periodic Minute event interrupt has occurred.
0 = Periodic Minute interrupt did not occur.
1 = Periodic Minute interrupt occurred (write 1 to clear).
1
SECFL
R/W
0
Flag indicating whether a periodic Second event interrupt has occurred.
0 = Periodic Second interrupt did not occur.
1 = Periodic Second interrupt occurred (write 1 to clear).
0
MSFL
R/W
0
Flag indicating whether a periodic Millisecond event interrupt has occurred.
0 = Periodic Millisecond interrupt did not occur.
1 = Periodic Millisecond interrupt occurred (write 1 to clear).
Real-Time Clock (RTC)
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1.3.2.18 RTCNOPWR Register
The RTC lost power status register (RTCNOPWR) is shown in Figure 1-20 and described in Table 1-23.
Figure 1-20. RTCNOPWR Register
15
1
0
Reserved
PWRUP
R-0
R-1
LEGEND: R = Read only; -n = value after reset
Table 1-23. RTCNOPWR Register Field Descriptions
Bit
Field
Type
Reset Description
15-1
Reserved
R
0
Reserved.
0
PWRUP
R
1
RTC has lost power Flag.
0 = RTC has not lost power since software reset.
1 = RTC has lost power and requires a software reset and initialization of the time
registers to the current time and date.
PWRUP is cleared by a read of RTCINTFL or RTCNOPWR. Therefore, read
RTCNOPWR before reading RTCINTFL to obtain the correct PWRUP value.
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1.3.2.19 RTCINTREG Register
The RTC interrupt register (RTCINTREG) is shown in Figure 1-21 and described in Table 1-24.
Figure 1-21. RTCINTREG Register
15
14
8
ALARMINTEN
Reserved
R/W-0
R-0
7
5
4
3
2
1
0
Reserved
6
EXTINTEN
DAYINTEN
HOURINTEN
MININTEN
SECINTEN
MSINTEN
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-24. RTCINTREG Register Field Descriptions
Bit
Field
Type
15
ALARMINTEN
R/W
0
Alarm interrupt enable.
0 = Alarm interrupt not enabled.
1 = Alarm interrupt enabled.
R
0
Reserved.
14-6
30
Reserved
Reset Description
5
EXTINTEN
R/W
0
External event (WAKEUP pin) interrupt enable.
0 = External event interrupt not enabled.
1 = External event interrupt enabled.
4
DAYINTEN
R/W
0
Periodic Day interrupt enable.
0 = Periodic Day interrupt not enabled.
1 = Periodic Day interrupt enabled.
3
HOURINTEN
R/W
0
Periodic Hour interrupt enable.
0 = Periodic Hour interrupt not enabled.
1 = Periodic Hour interrupt enabled.
2
MININTEN
R/W
0
Periodic Minute interrupt enable.
0 = Periodic Minute interrupt not enabled.
1 = Periodic Minute interrupt enabled.
1
SECINTEN
R/W
0
Periodic Second interrupt enable.
0 = Periodic Second interrupt not enabled.
1 = Periodic Second interrupt enabled.
0
MSINTEN
R/W
0
Periodic Millisecond interrupt enable.
0 = Periodic Millisecond interrupt not enabled.
1 = Periodic Millisecond interrupt enabled.
Real-Time Clock (RTC)
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1.3.2.20 RTCDRIFT Register
Every hour on the hour, a positive or negative number of milliseconds is added to the milliseconds register
to compensate for inaccuracy in the 32.768kHz crystal based on the value of COMP[3:0]. If this value is 0
then no compensation will be applied.
Any positive compensation value must not be a multiple of 10.
The RTC compensation register (RTCDRIFT) is shown in Figure 1-22 and described in Table 1-25.
Figure 1-22. RTCDRIFT Register
15
14
13
12
11
8
7
4
3
0
DRIFT
Reserved
COMP3
COMP2
COMP1
COMP0
RW-0
R-0
RW-0
RW-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-25. RTCDRIFT Register Field Descriptions
Bit
Field
Type
15
DRIFT
R/W
0
Positive or Negative Compensation.
0 = Negative compensation.
1 = Positive compensation
14-13 Reserved
Reset Description
R
0
Reserved.
12
COMP3
R/W
0
Digit 3 of Compensation in BCD format.
0 = Digit 3 of Compensation is 0.
1 = Digit 3 of Compensation is 1.
11-8
COMP2
R/W
0
Digit 2 of Compensation register in BCD format, value 0 to 9
7-4
COMP1
R/W
0
Digit 1 of Compensation register in BCD format, value 0 to 9
3-0
COMP0
R/W
0
Digit 0 of Compensation register in BCD format. Value = 0-9, value 0 to 9
1.3.2.21 RTCOSC Register
The RTC oscillator register (RTCOSC) is shown in Figure 1-23 and described in Table 1-26.
Figure 1-23. RTCOSC Register
15
14
4
3
0
RTCRESET
Reserved
OSCRES
W-0
R-0
RW-1011b
LEGEND: R/W = Read/Write; R = Read only; W = Write only; n = value after reset
Table 1-26. RTCOSC Register Field Descriptions
Bit
Field
15
RTCRESET
Type
Reset Description
W
14-4
Reserved
R
3-0
OSCRES
R/W
0
RTC software reset. The RTC only resets when this bit is set. The RTC is not reset
when RESTN goes low. Once set, this bit is cleared by the RTC. Do not access any
RTC register for three 32.768kHz clock cycles after setting this bit.
0 = RTC not reset.
1 = RTC reset.
0
Reserved.
1011b Value of the oscillator cell's internal resistor. The default (reset state) is 1011b and this
gives faster startup but higher power. Once the oscillator is running it can be changed
to 1000b for lower power consumption, value 0 to Fh.
1.3.2.22 RTCPMGT Register
The RTC power management register (RTCPMGT) is shown in Figure 1-24 and described in Table 1-27.
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Figure 1-24. RTCPMGT Register
15
5
4
3
2
1
0
Reserved
WU_DOUT
WU_DIR
BG_PD
LDO_PD
RTCCLKOUTEN
R-0
RW-1
RW-0
RW-0
RW-0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-27. RTCPMGT Register Field Descriptions
Bit
15-5
Field
Reserved
Type
R
Reset Description
0
Reserved.
4
WU_DOUT
R/W
0
Wake-up output, active low/open-drain.
0 = WAKEUP pin driven low.
1 = WAKEUP pin is in high impedance.
3
WU_DIR
R/W
0
Wake-up pin direction control.
0 = WAKEUP pin is configured as input.
1 = WAKEUP pin is configured as output
Note: The WAKEUP pin, when configured as an input, is active high. When it is
configured as an output, it is open-drain and thus it should have an external pullup
and it is active low.
32
2
BG_PD
R/W
0
Bandgap, on-chip LDOs, and the analog POR power down bit.
This bit shuts down the on-chip LDOs (ANA_LDO, DSP_LDO, and USB_LDO), the
Analog POR, and Bandgap reference. BG_PD and LDO_PD are only intended to be
used when the internal LDOs supply power to the chip. If the internal LDOs are
bypassed and not used then the BG_PD and LDO_PD power down mechanisms
should not be used since POR gets powered down and the POWERGOOD signal is
not generated properly.
After this bit is asserted, the on-chip LDOs, Analog POR, and the Bandgap reference
can be re-enabled by the WAKEUP pin (high) or the RTC alarm interrupt. The
Bandgap circuit will take about 100 msec to charge the external 0.1 uF capacitor via
the internal 326-kΩ resistor.
0 = On-chip LDOs, Analog POR, and Bandgap reference are enabled.
1 = On-chip LDOs, Analog POR, and Bandgap reference are disabled (shutdown).
1
LDO_PD
R/W
0
On-chip LDOs and Analog POR power down bit.
This bit shuts down the on-chip LDOs (ANA_LDO, DSP_LDO, and USB_LDO) and the
Analog POR. BG_PD and LDO_PD are only intended to be used when the internal
LDOs supply power to the chip. If the internal LDOs are bypassed and not used then
the BG_PD and LDO_PD power down mechanisms should not be used since POR
gets powered down and the POWERGOOD signal is not generated properly.
After this bit is asserted, the on-chip LDOs and Analog POR can be re-enabled by the
WAKEUP pin (high) or the RTC alarm interrupt. This bit keeps the Bandgap reference
turned on to allow a faster wake-up time with the expense power consumption of the
Bandgap reference.
0 = On-chip LDOs and Analog POR are enabled.
1 = On-chip LDOs and Analog POR are disabled (shutdown).
0
RTCCLKOUTE
N
R/W
0
Clockout output enable.
0 = RTC clock output disabled
1 = RTC clock output enabled
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1.3.2.23 RTCSCR1 Register
The RTC Scratch Registers are general purpose memory that can be used to store a value that will be
preserved even when the DSP power is off.
The RTC LSW scratch register 1 (RTCSCR1) is shown in Figure 1-25 and described in Table 1-28.
Figure 1-25. RTCSCR1 Register
15
0
SCRATCH0
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-28. RTCSCR1 Register 1 Field Descriptions
Bit
15-0
Field
Type
Reset
SCRATCH0
R/W
0
Description
Scratch registers, available to program, value 0 to FFFFh
1.3.2.24 RTCSCR2 Register
The RTC MSW scratch register 2 (RTCSCR2) is shown in Figure 1-26 and described in Table 1-29.
Figure 1-26. RTCSCR2 Register
15
0
SCRATCH2
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-29. RTCSCR2 Register Field Descriptions
Bit
15-0
Field
Type
Reset
SCRATCH2
R/W
0
Description
Scratch registers, available to program, value 0 to FFFFh
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1.3.2.25 RTCSCR3 Register
The RTC LSW scratch register 3 (RTCSCR3) is shown in Figure 1-27 and described in Table 1-30.
Figure 1-27. RTCSCR3 Register
15
0
SCRATCH3
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-30. RTCSCR3 Register Field Descriptions
Bit
15-0
Field
Type
Reset
SCRATCH3
R/W
0
Description
Scratch registers, available to program, value 0 to FFFFh
1.3.2.26 RTCSCR4 Register
The RTC MSW scratch register 4 (RTCSCR4) is shown in Figure 1-28 and described in Table 1-31.
Figure 1-28. RTCSCR4 Register
15
0
SCRATCH4
RW-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 1-31. RTCSCR4 Register Field Descriptions
Bit
15-0
34
Field
Type
Reset
SCRATCH4
R/W
0
Real-Time Clock (RTC)
Description
Scratch registers, available to program, value 0 to FFFFh.
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Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
This revision history highlights the changes made to this document from its previous version.
Revision History
See
Revision
Section 1.2.2,
Device Configuration
Updated description of when the RTC interrupt will trigger in Section 1.2.2, Signal
Descriptions.
Section 1.2.3,
RTC-Only Mode
Updated description of RTC during wake up and power down for RTC-only mode.
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