AT90S1200

AT90S1200
Features
• Utilizes the AVR® RISC Architecture
• AVR – High-performance and Low-power RISC Architecture
•
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•
•
•
•
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– 89 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General-purpose Working Registers
– Up to 12 MIPS Throughput at 12 MHz
Data and Nonvolatile Program Memory
– 1K Byte of In-System Programmable Flash
Endurance: 1,000 Write/Erase Cycles
– 64 Bytes of In-System Programmable EEPROM
Endurance: 100,000 Write/Erase Cycles
– Programming Lock for Flash Program and EEPROM Data Security
Peripheral Features
– One 8-bit Timer/Counter with Separate Prescaler
– On-chip Analog Comparator
– Programmable Watchdog Timer with On-chip Oscillator
– SPI Serial Interface for In-System Programming
Special Microcontroller Features
– Low-power Idle and Power-down Modes
– External and Internal Interrupt Sources
– Selectable On-chip RC Oscillator for Zero External Components
Specifications
– Low-power, High-speed CMOS Process Technology
– Fully Static Operation
Power Consumption at 4 MHz, 3V, 25°C
– Active: 2.0 mA
– Idle Mode: 0.4 mA
– Power-down Mode: <1 µA
I/O and Packages
– 15 Programmable I/O Lines
– 20-pin PDIP, SOIC and SSOP
Operating Voltages
– 2.7 - 6.0V (AT90S1200-4)
– 4.0 - 6.0V (AT90S1200-12)
Speed Grades
– 0 - 4 MHz, (AT90S1200-4)
– 0 - 12 MHz, (AT90S1200-12)
8-bit
Microcontroller
with 1K Byte
of In-System
Programmable
Flash
AT90S1200
Description
The AT90S1200 is a low-power CMOS 8-bit microcontroller based on the AVR RISC
architecture. By executing powerful instructions in a single clock cycle, the
(continued)
Pin Configuration
Rev. 0838F–10/00
1
AT90S1200 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
The AVR core combines a rich instruction set with the 32 general-purpose working registers. All the 32 registers are directly
connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction
executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times
faster than conventional CISC microcontrollers.
Block Diagram
Figure 1. The AT90S1200 Block Diagram
2
AT90S1200
AT90S1200
The architecture supports high-level languages efficiently as well as extremely dense assembler code programs. The
AT90S1200 provides the following features: 1K byte of In-System Programmable Flash, 64 bytes EEPROM, 15 generalpurpose I/O lines, 32 general-purpose working registers, internal and external interrupts, programmable watchdog timer
with internal oscillator, an SPI serial port for program downloading and two software selectable power-saving modes. The
Idle Mode stops the CPU while allowing the registers, timer/counter, watchdog and interrupt system to continue functioning.
The Power-down Mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next
external interrupt or hardware reset.
The device is manufactured using Atmel’s high-density nonvolatile memory technology. The on-chip In-System Programmable Flash allows the program memory to be reprogrammed in-system through an SPI serial interface or by a
conventional nonvolatile memory programmer. By combining an enhanced RISC 8-bit CPU with In-System Programmable
Flash on a monolithic chip, the Atmel AT90S1200 is a powerful microcontroller that provides a highly flexible and costeffective solution to many embedded control applications.
The AT90S1200 AVR is supported with a full suite of program and system development tools including: macro assemblers,
program debugger/simulators, in-circuit emulators, and evaluation kits.
Pin Descriptions
VCC
Supply voltage pin.
GND
Ground pin.
Port B (PB7..PB0)
Port B is an 8-bit bi-directional I/O port. Port pins can provide internal pull-up resistors (selected for each bit). PB0 and PB1
also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip analog comparator. The
Port B output buffers can sink 20 mA and thus drive LED displays directly. When pins PB0 to PB7 are used as inputs and
are externally pulled low, they will source current if the internal pull-up resistors are activated. The Port B pins are tri-stated
when a reset condition becomes active, even if the clock is not active.
Port B also serves the functions of various special features of the AT90S1200 as listed on page 26.
Port D (PD6..PD0)
Port D has seven bi-directional I/O pins with internal pull-up resistors, PD6..PD0. The Port D output buffers can sink 20 mA.
As inputs, Port D pins that are externally pulled low will source current if the pull-up resistors are activated. The Port D pins
are tri-stated when a reset condition becomes active, even if the clock is not active.
Port D also serves the functions of various special features of the AT90S1200 as listed on page 30.
RESET
Reset input. A low level on this pin for more than 50 ns will generate a reset, even if the clock is not running. Shorter pulses
are not guaranteed to generate a reset.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2
Output from the inverting oscillator amplifier.
3
Crystal Oscillator
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be configured for use as an onchip oscillator, as shown in Figure 2. Either a quartz crystal or a ceramic resonator may be used. To drive the device from
an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 3.
Figure 2. Oscillator Connections
MAX 1 HC BUFFER
HC
C2
C1
XTAL2
XTAL1
GND
Note:
When using the MCU Oscillator as a clock for an external device, an HC buffer should be connected as indicated in the figure.
Figure 3. External Clock Drive Configuration
On-chip RC Oscillator
An on-chip RC oscillator running at a fixed frequency of 1 MHz can be selected as the MCU clock source. If enabled, the
AT90S1200 can operate with no external components. A control bit (RCEN) in the Flash Memory selects the on-chip RC
oscillator as the clock source when programmed (“0”). The AT90S1200 is normally shipped with this bit unprogrammed
(“1”). Parts with this bit programmed can be ordered as AT90S1200A. The RCEN-bit can be changed by parallel programming only. When using the on-chip RC oscillator for serial program downloading, the RCEN bit must be programmed in
Parallel Programming Mode first.
Architectural Overview
The fast-access register file concept contains 32 x 8-bit general-purpose working registers with a single clock cycle access
time. This means that during one single clock cycle, one ALU (Arithmetic Logic Unit) operation is executed. Two operands
are output from the register file, the operation is executed, and the result is stored back in the register file – in one clock
cycle.
4
AT90S1200
AT90S1200
Figure 4. The AT90S1200 AVR RISC Architecture
The ALU supports arithmetic and logic functions between registers or between a constant and a register. Single register
operations are also executed in the ALU. Figure 4 shows the AT90S1200 AVR RISC microcontroller architecture. The AVR
uses a Harvard architecture concept – with separate memories and buses for program and data memories. The program
memory is accessed with a 2-stage pipeline. While one instruction is being executed, the next instruction is pre-fetched
from the program memory. This concept enables instructions to be executed in every clock cycle. The program memory is
In-System Programmable Flash memory.
With the relative jump and relative call instructions, the whole 512 address space is directly accessed. All AVR instructions
have a single 16-bit word format, meaning that every program memory address contains a single 16-bit instruction.
During interrupts and subroutine calls, the return address program counter (PC) is stored on the stack. The stack is a
3-level-deep hardware stack dedicated for subroutines and interrupts.
The I/O memory space contains 64 addresses for CPU peripheral functions such as control registers, timer/counters, A/D
converters and other I/O functions. The memory spaces in the AVR architecture are all linear and regular memory maps.
A flexible interrupt module has its control registers in the I/O space with an additional global interrupt enable bit in the status
register. All the different interrupts have a separate interrupt vector in the interrupt vector table at the beginning of the
program memory. The different interrupts have priority in accordance with their interrupt vector position. The lower the
interrupt vector address, the higher the priority.
5
General-purpose Register File
Figure 5 shows the structure of the 32 general-purpose registers in the CPU.
Figure 5. AVR CPU General-purpose Working Registers
7
0
R0
R1
R2
General
…
Purpose
…
Working
R28
Registers
R29
R30 (Z-Register)
R31
All the register operating instructions in the instruction set have direct and single cycle access to all registers. The only
exception is the five constant arithmetic and logic instructions SBCI, SUBI, CPI, ANDI, ORI between a constant and a
register and the LDI instruction for load immediate constant data. These instructions apply to the second half of the
registers in the register file (R16..R31). The general SBC, SUB, CP, AND, OR and all other operations between two registers or on a single register apply to the entire register file.
Register 30 also serves as an 8-bit pointer for indirect address of the register file.
ALU – Arithmetic Logic Unit
The high-performance AVR ALU operates in direct connection with all the 32 general-purpose working registers. Within a
single clock cycle, ALU operations between registers in the register file are executed. The ALU operations are divided into
three main categories – arithmetic, logic and bit-functions.
In-System Programmable Flash Program Memory
The AT90S1200 contains 1K bytes on-chip In-System Programmable Flash memory for program storage. Since all instructions are single 16-bit words, the Flash is organized as 512 x 16. The Flash memory has an endurance of at least 1000
write/erase cycles.
The AT90S1200 Program Counter is 9 bits wide, thus addressing the 512 words Flash program memory.
See page 33 for a detailed description on Flash data downloading.
Program and Data Addressing Modes
The AT90S1200 AVR RISC Microcontroller supports powerful and efficient addressing modes. This section describes the
different addressing modes supported in the AT90S1200. In the figures, OP means the operation code part of the instruction word. To simplify, not all figures show the exact location of the addressing bits.
6
AT90S1200
AT90S1200
Register Direct, Single Register Rd
Figure 6. Direct Single Register Addressing
The operand is contained in register d (Rd).
Register Indirect
Figure 7. Indirect Register Addressing
The register accessed is the one pointed to by the Z-register (R30).
7
Register Direct, Two Registers Rd and Rr
Figure 8. Direct Register Addressing, Two Registers
Operands are contained in register r (Rr) and d (Rd). The result is stored in register d (Rd).
I/O Direct
Figure 9. I/O Direct Addressing
Operand address is contained in 6 bits of the instruction word. n is the destination or source register address.
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AT90S1200
AT90S1200
Relative Program Addressing, RJMP and RCALL
Figure 10. Relative Program Memory Addressing
Program execution continues at address PC + k + 1. The relative address k is -2048 to 2047.
Subroutine and Interrupt Hardware Stack
The AT90S1200 uses a 3 level deep hardware stack for subroutines and interrupts. The hardware stack is 9 bits wide and
stores the Program Counter (PC) return address while subroutines and interrupts are executed.
RCALL instructions and interrupts push the PC return address onto stack level 0, and the data in the other stack levels 1 - 2
are pushed one level deeper in the stack. When a RET or RETI instruction is executed the returning PC is fetched from
stack level 0, and the data in the other stack levels 1 - 2 are popped one level in the stack.
If more than three subsequent subroutine calls or interrupts are executed, the first values written to the stack are
overwritten.
EEPROM Data Memory
The AT90S1200 contains 64 bytes of data EEPROM memory. It is organized as a separate data space, in which single
bytes can be read and written. The EEPROM has an endurance of at least 100,000 write/erase cycles. The access
between the EEPROM and the CPU is described on page 22 specifying the EEPROM address register, the EEPROM data
register, and the EEPROM control register. For the SPI data downloading, see page 40 for a detailed description.
Instruction Execution Timing
This section describes the general access timing concepts for instruction execution and internal memory access.
The AVR CPU is driven by the System Clock Ø, directly generated from the external clock crystal for the chip. No internal
clock division is used.
Figure 11 shows the parallel instruction fetches and instruction executions enabled by the Harvard architecture and the
fast-access register file concept. This is the basic pipelining concept to obtain up to 1 MIPS per MHz with the corresponding
unique results for functions per cost, functions per clocks, and functions per power-unit.
9
Figure 11. The Parallel Instruction Fetches and Instruction Executions
T1
T2
T3
T4
System Clock Ø
1st Instruction Fetch
1st Instruction Execute
2nd Instruction Fetch
2nd Instruction Execute
3rd Instruction Fetch
3rd Instruction Execute
4th Instruction Fetch
Figure 12 shows the internal timing concept for the register file. In a single clock cycle an ALU operation using two register
operands is executed, and the result is stored back to the destination register.
Figure 12. Single-cycle ALU Operation
T1
T2
System Clock Ø
Total Execution Time
Register Operands Fetch
ALU Operation Execute
Result Write Back
I/O Memory
The I/O space definition of the AT90S1200 is shown in the following table.
Table 1. The AT90S1200 I/O Space
10
Address Hex
Name
Function
$3F
SREG
Status REGister
$3B
GIMSK
General Interrupt MaSK register
$39
TIMSK
Timer/Counter Interrupt MaSK register
$38
TIFR
$35
MCUCR
MCU general Control Register
$33
TCCR0
Timer/Counter 0 Control Register
$32
TCNT0
Timer/Counter 0 (8-bit)
$21
WDTCR
Watchdog Timer Control Register
$1E
EEAR
EEPROM Address Register
$1D
EEDR
EEPROM Data Register
$1C
EECR
EEPROM Control Register
Timer/Counter Interrupt Flag register
AT90S1200
T3
T4
AT90S1200
Table 1. The AT90S1200 I/O Space (Continued)
Address Hex
Name
$18
PORTB
Data Register, Port B
$17
DDRB
Data Direction Register, Port B
$16
PINB
Input Pins, Port B
$12
PORTD
Data Register, Port D
$11
DDRD
Data Direction Register, Port D
$10
PIND
Input Pins, Port D
$08
ACSR
Analog Comparator Control and Status Register
Note:
Function
Reserved and unused locations are not shown in the table.
All AT90S1200 I/Os and peripherals are placed in the I/O space. The different I/O locations are accessed by the IN and
OUT instructions transferring data between the 32 general-purpose working registers and the I/O space. I/O registers
within the address range $00 - $1F are directly bit-accessible using the SBI and CBI instructions. In these registers, the
value of single bits can be checked by using the SBIS and SBIC instructions. Refer to the instruction set chapter for more
details.
For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses
should never be written.
Some of the status flags are cleared by writing a logical one to them. Note that the CBI and SBI instructions will operate on
all bits in the I/O register, writing a one back into any flag read as set, thus clearing the flag. The CBI and SBI instructions
work with registers $00 to $1F only.
The different I/O and peripherals control registers are explained in the following sections.
Status Register – SREG
The AVR status register (SREG) at I/O space location $3F is defined as:
Bit
7
6
5
4
3
2
1
0
$3F
I
T
H
S
V
N
Z
C
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
SREG
• Bit 7 – I: Global Interrupt Enable
The global interrupt enable bit must be set (one) for the interrupts to be enabled. The individual interrupt enable control is
then performed in separate control registers. If the global interrupt enable bit is cleared (zero), none of the interrupts are
enabled independent of the individual interrupt enable settings. The I-bit is cleared by hardware after an interrupt has
occurred, and is set by the RETI instruction to enable subsequent interrupts.
• Bit 6 – T: Bit Copy Storage
The bit copy instructions BLD (Bit LoaD) and BST (Bit STore) use the T-bit as source and destination for the operated bit. A
bit from a register in the register file can be copied into T by the BST instruction, and a bit in T can be copied into a bit in a
register in the register file by the BLD instruction.
• Bit 5 – H: Half-carry Flag
The half-carry flag H indicates a half carry in some arithmetic operations. See the Instruction Set description for detailed
information.
• Bit 4 – S: Sign Bit, S = N⊕V
The S-bit is always an exclusive or between the negative flag N and the two’s complement overflow flag V. See the Instruction Set description for detailed information.
• Bit 3 – V: Two’s Complement Overflow Flag
The two’s complement overflow flag V supports two’s complement arithmetics. See the Instruction Set description for
detailed information.
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• Bit 2 – N: Negative Flag
The negative flag N indicates a negative result after the different arithmetic and logic operations. See the Instruction Set
description for detailed information.
• Bit 1 – Z: Zero Flag
The zero flag Z indicates a zero result after the different arithmetic and logic operations. See the Instruction Set description
for detailed information.
• Bit 0 – C: Carry Flag
The carry flag C indicates a carry in an arithmetic or logic operation. See the Instruction Set description for detailed
information.
Note that the status register is not automatically stored when entering an interrupt routine and restored when returning from
an interrupt routine. This must be handled by software.
Reset and Interrupt Handling
The AT90S1200 provides three different interrupt sources. These interrupts and the separate reset vector, each have a
separate program vector in the program memory space. All the interrupts are assigned individual enable bits that must be
set (one) together with the I-bit in the Status Register in order to enable the interrupt.
The lowest addresses in the program memory space are automatically defined as the Reset and Interrupt vectors. The
complete list of vectors is shown in Table 2. The list also determines the priority levels of the different interrupts. The lower
the address the higher is the priority level. RESET has the highest priority, and next is INT0 (the External Interrupt Request
0), etc.
Table 2. Reset and Interrupt Vectors
Vector No.
Program Address
Source
Interrupt Definition
1
$000
RESET
Hardware Pin, Power-on Reset and Watchdog Reset
2
$001
INT0
4
$002
TIMER0, OVF0
5
$003
ANA_COMP
External Interrupt Request 0
Timer/Counter0 Overflow
Analog Comparator
The most typical and general program setup for the Reset and Interrupt Vector Addresses are:
Address
Labels
Code
Comments
$000
rjmp
RESET
; Reset Handler
$001
rjmp
EXT_INT0
; IRQ0 Handler
$002
rjmp
TIM0_OVF
; Timer0 Overflow Handler
$003
rjmp
ANA_COMP
; Analog Comparator Handler
MAIN:
<instr>
xxx
; Main program start
…
…
;
$004
…
…
Reset Sources
The AT90S1200 has three sources of reset:
• Power-on Reset. The MCU is reset when the supply voltage is below the power-on reset threshold (VPOT).
• External Reset. The MCU is reset when a low level is present on the RESET pin for more than 50 ns.
• Watchdog Reset. The MCU is reset when the Watchdog timer period expires and the Watchdog is enabled.
During reset, all I/O registers are then set to their initial values, and the program starts execution from address $000. The
instruction placed in address $000 must be an RJMP (relative jump) instruction to the reset handling routine. If the
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AT90S1200
AT90S1200
program never enables an interrupt source, the interrupt vectors are not used, and regular program code can be placed at
these locations. The circuit diagram in Figure 13 shows the reset logic. Table 3 defines the timing and electrical parameters
of the reset circuitry. Note that Power-on Reset timing is clocked by the internal RC oscillator. Refer to characterization
data for RC oscillator frequency at other VCC voltages.
Figure 13. Reset Logic
Table 3. Reset Characteristics (VCC = 5.0V)
Symbol
VPOT(1)
Parameter
Min
Typ
Max
Units
Power-on Reset Threshold Voltage (rising)
0.8
1.2
1.6
V
Power-on Reset Threshold Voltage (falling)
0.2
0.4
0.6
V
VRST
Pin Threshold Voltage
–
–
0.85 VCC
V
tPOR
Power-on Reset Period
2.0
3.0
4.0
ms
tTOUT
Reset Delay Time-out Period (The Time-out
period equals 16K WDT cycles. See “Typical
Characteristics” on page 47 for typical WDT
frequency at different voltages).
11.0
16.0
21.0
ms
Notes:
1. The Power-on Reset will not work unless the supply voltage has been below VPOT (falling).
Power-on Reset
A Power-on Reset (POR) circuit ensures that the device is reset from power-on. As shown in Figure 13, an internal timer
clocked from the Watchdog timer oscillator prevents the MCU from starting until after a certain period after V CC has
reached the Power-on Threshold voltage (VPOT), regardless of the VCC rise time (see Figure 14).
13
Figure 14. MCU Start-up, RESET Tied to VCC.
VCC
RESET
VPOT
VRST
tTOUT
TIME-OUT
INTERNAL
RESET
If the built-in start-up delay is sufficient, RESET can be connected to VCC directly or via an external pull-up resistor. By holding the RESET pin low for a period after VCC has been applied, the Power-on Reset period can be extended. Refer to
Figure 15 for a timing example on this.
Figure 15. MCU Start-up, RESET Controlled Externally
VCC
VPOT
RESET
TIME-OUT
VRST
tTOUT
INTERNAL
RESET
External Reset
An external reset is generated by a low level on the RESET pin. Reset pulses longer than 50 ns will generate a reset, even
if the clock is not running. Shorter pulses are not guaranteed to generate a reset. When the applied signal reaches the
Reset Threshold Voltage (VRST) on its positive edge, the delay timer starts the MCU after the Time-out period tTOUT has
expired.
14
AT90S1200
AT90S1200
Figure 16. External Reset during Operation
VCC
RESET
TIME-OUT
INTERNAL
RESET
Watchdog Reset
When the Watchdog times out, it will generate a short reset pulse of 1 XTAL cycle duration. On the falling edge of this
pulse, the delay timer starts counting the Time-out period tTOUT. Refer to page 21 for details on operation of the Watchdog.
Figure 17. Watchdog Reset during Operation
Interrupt Handling
The AT90S1200 has two Interrupt Mask control registers: the GIMSK (General Interrupt Mask register) at I/O space
address $3B and the TIMSK (Timer/Counter Interrupt Mask register) at I/O address $39.
When an interrupt occurs, the Global Interrupt Enable I-bit is cleared (zero) and all interrupts are disabled. The user
software can set (one) the I-bit to enable interrupts. The I-bit is set (one) when a Return from Interrupt instruction (RETI) is
executed.
When the Program Counter is vectored to the actual interrupt vector in order to execute the interrupt handling routine, hardware clears the corresponding flag that generated the interrupt. Some of the interrupt flags can also be cleared by writing a
logic one to the flag bit position(s) to be cleared.
If an interrupt condition occurs when the corresponding interrupt enable bit is cleared (zero), the interrupt flag will be set
and remembered until the interrupt is enabled, or the flag is cleared by software.
If one or more interrupt conditions occur when the global interrupt enable bit is cleared (zero), the corresponding interrupt
flag(s) will be set and remembered until the global interrupt enable bit is set (one), and will be executed by order of priority.
Note that external level interrupt does not have a flag, and will only be remembered for as long as the interrupt condition is
active.
15
Note that the Status Register is not automatically stored when entering an interrupt routine and restored when returning
from an interrupt routine. This must be handled by software.
General Interrupt Mask Register – GIMSK
Bit
7
6
5
4
3
2
1
$3B
-
INT0
-
-
-
-
-
0
-
Read/Write
R
R/W
R
R
R
R
R
R
Initial value
0
0
0
0
0
0
0
0
GIMSK
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the AT90S1200 and always reads as zero.
• Bit 6 – INT0: External Interrupt Request 0 Enable
When the INT0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the external pin interrupt is enabled.
The Interrupt Sense Control0 bit 1/0 (ISC01 and ISC00) in the MCU general Control Register (MCUCR) defines whether
the external interrupt is activated on rising or falling edge of the INT0 pin or low level sensed. INT0 can be activated even if
the pin is configured as an output. See also page 17.
• Bits 5..0 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
Timer/Counter Interrupt Mask Register – TIMSK
Bit
7
6
5
4
3
2
1
$39
-
-
-
-
-
-
TOIE0
0
-
Read/Write
R
R
R
R
R
R
R/W
R
Initial value
0
0
0
0
0
0
0
0
TIMSK
• Bits 7..2 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
• Bit 1 – TOIE0: Timer/Counter0 Overflow Interrupt Enable
When the TOIE0 bit is set (one) and the I-bit in the Status Register is set (one), the Timer/Counter0 Overflow interrupt is
enabled. The corresponding interrupt (at vector $002) is executed if an overflow in Timer/Counter0 occurs, i.e., when the
TOV0 bit is set in the Timer/Counter Interrupt Flag Register (TIFR).
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the AT90S1200 and always reads as zero.
Timer/Counter Interrupt FLAG Register – TIFR
Bit
7
6
5
4
3
2
1
$38
-
-
-
-
-
-
TOV0
0
-
Read/Write
R
R
R
R
R
R
R/W
R
Initial value
0
0
0
0
0
0
0
0
TIFR
• Bits 7..2 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
• Bit 1 – TOV0: Timer/Counter0 Overflow Flag
The bit TOV0 is set (one) when an overflow occurs in Timer/Counter0. TOV0 is cleared by hardware when executing the
corresponding interrupt handling vector. Alternatively, TOV0 is cleared by writing a logic one to the flag. When the SREG Ibit, and TOIE0 (Timer/Counter0 Overflow Interrupt Enable), and TOV0 are set (one), the Timer/Counter0 Overflow interrupt
is executed.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the AT90S1200 and always reads as zero.
16
AT90S1200
AT90S1200
External Interrupts
The external interrupt is triggered by the INT0 pin. The interrupt can trigger on rising edge, falling edge or low level. This is
set up as described in the specification for the MCU Control Register (MCUCR). When INT0 is level triggered, the interrupt
is pending as long as INT0 is held low.
The interrupt is triggered even if INT0 is configured as an output. This provides a way to generate a software interrupt.
The interrupt flag can not be directly accessed by the user. If an external edge-triggered interrupt is suspected to be
pending, the flag can be cleared as follows.
1. Disable the external interrupt by clearing the INT0 flag in GIMSK.
2. Select level triggered interrupt.
3. Select desired interrupt edge.
4. Re-enable the external interrupt by setting INT0 in GIMSK.
Interrupt Response Time
The interrupt execution response for all the enabled AVR interrupts is four clock cycles minimum. Four clock cycles after
the interrupt flag has been set, the program vector address for the actual interrupt handling routine is executed. During this
4-clock-cycle period, the Program Counter (9 bits) is pushed onto the Stack. The vector is normally a relative jump to the
interrupt routine, and this jump takes 2 clock cycles. If an interrupt occurs during execution of a multi-cycle instruction, this
instruction is completed before the interrupt is served.
A return from an interrupt handling routine takes four clock cycles. During these four clock cycles, the Program Counter (9
bits) is popped back from the Stack and the I-flag in SREG is set. When the AVR exits from an interrupt, it will always return
to the main program and execute one more instruction before any pending interrupt is served.
Note that the Subroutine and Interrupt Stack is a 3-level true hardware stack, and if more than three nested subroutines
and interrupts are executed, only the most recent three return addresses are stored.
MCU Control Register – MCUCR
The MCU Control Register contains general microcontroller control bits for general MCU control functions.
Bit
7
6
5
4
3
2
1
0
$35
–
–
SE
SM
–
–
ISC01
ISC00
Read/Write
R
R
R/W
R/W
R
R
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
MCUCR
• Bits 7, 6 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
• Bit 5 – SE: Sleep Enable
The SE bit must be set (one) to make the MCU enter the Sleep Mode when the SLEEP instruction is executed. To avoid
the MCU entering the Sleep Mode unless it is the programmers purpose, it is recommended to set the Sleep Enable SE bit
just before the execution of the SLEEP instruction.
• Bit 4 – SM: Sleep Mode
This bit selects between the two available sleep modes. When SM is cleared (zero), Idle Mode is selected as Sleep Mode.
When SM is set (one), Power-down Mode is selected as Sleep Mode. For details, refer to the paragraph “Sleep Modes” on
the following page.
• Bits 3, 2 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
• Bits 1, 0 – ISC01, ISC00: Interrupt Sense Control 0 Bit 1 and Bit 0
The External Interrupt 0 is activated by the external pin INT0 if the SREG I-flag and the corresponding interrupt mask in the
GIMSK register is set. The level and edges on the external INT0 pin that activate the interrupt are defined in Table 4.
17
Table 4. Interrupt 0 Sense Control
ISC01
ISC00
Description
0
0
The low level of INT0 generates an interrupt request.
0
1
Reserved
1
0
The falling edge of INT0 generates an interrupt request.
1
1
The rising edge of INT0 generates an interrupt request.
The value on the INT0 pin is sampled before detecting edges. If edge interrupt is selected, pulses with a duration longer
than one CPU clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low
level interrupt is selected, the low level must be held until the completion of the currently executing instruction to generate
an interrupt. If enabled, a level triggered interrupt will generate an interrupt request as long as the pin is held low.
Sleep Modes
To enter the sleep modes, the SE bit in MCUCR must be set (one) and a SLEEP instruction must be executed. If an
enabled interrupt occurs while the MCU is in a sleep mode, the MCU awakes, executes the interrupt routine, and resumes
execution from the instruction following SLEEP. The contents of the register file and the I/O memory are unaltered. If a
reset occurs during Sleep Mode, the MCU wakes up and executes from the Reset vector.
Idle Mode
When the SM bit is cleared (zero), the SLEEP instruction makes the MCU enter the Idle Mode, stopping the CPU but allowing Timer/Counters, Watchdog and the interrupt system to continue operating. This enables the MCU to wake up from
external triggered interrupts as well as internal ones like Timer Overflow interrupt and Watchdog reset. If wakeup from the
Analog Comparator interrupt is not required, the analog comparator can be powered down by setting the ACD-bit in the
Analog Comparator Control and Status Register (ACSR). This will reduce power consumption in Idle Mode. When the MCU
wakes up from Idle Mode, the CPU starts program execution immediately.
Power-down Mode
When the SM bit is set (one), the SLEEP instruction makes the MCU enter Power-down Mode. In this mode, the external
oscillator is stopped while the external interrupts and the Watchdog (if enabled) continue operating. Only an external reset,
a Watchdog reset (if enabled), an external level interrupt on INT0 can wake up the MCU.
Note that when a level triggered interrupt is used for wake-up from power-down, the low level must be held for a time longer
than the reset delay time-out period tTOUT. Otherwise, the device will not wake up.
Timer/Counter0
The AT90S1200 provides one general-purpose 8-bit Timer/Counter. The Timer/Counter0 gets the prescaled clock from the
10-bit prescaling timer. The Timer/Counter0 can either be used as a timer with an internal clock time base or as a counter
with an external pin connection, which triggers the counting.
18
AT90S1200
AT90S1200
Timer/Counter0 Prescaler
Figure 18 shows the general Timer/Counter0 prescaler.
Figure 18. Timer/Counter0 Prescaler
T0
TCK0
The four different prescaled selections are: CK/8, CK/64, CK/256 and CK/1024 where CK is the oscillator clock. For the
Timer/Counter0, added selections as CK, external clock source and stop, can be selected as clock sources. Figure 19
shows the block diagram for Timer/Counter0.
Figure 19. Timer/Counter 0 Block Diagram
T0
19
The 8-bit Timer/Counter0 can select clock source from CK, prescaled CK or an external pin. In addition it can be stopped
as described in the specification for the Timer/Counter0 Control Register (TCCR0). The overflow status flag is found in the
Timer/Counter Interrupt Flag Register (TIFR). Control signals are found in the Timer/Counter0 Control Register (TCCR0).
The interrupt enable/disable settings for Timer/Counter0 are found in the Timer/Counter Interrupt Mask Register (TIMSK).
When Timer/Counter0 is externally clocked, the external signal is synchronized with the oscillator frequency of the CPU. To
assure proper sampling of the external clock, the minimum time between two external clock transitions must be at least one
internal CPU clock period. The external clock signal is sampled on the rising edge of the internal CPU clock.
The 8-bit Timer/Counter0 features both a high-resolution and a high-accuracy usage with the lower prescaling opportunities. Similarly, the high prescaling opportunities make the Timer/Counter0 useful for lower speed functions or exact timing
functions with infrequent actions.
Timer/Counter0 Control Register – TCCR0
Bit
7
6
5
4
3
2
1
0
$33
-
-
-
-
-
CS02
CS01
CS00
Read/Write
R
R
R
R
R
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
TCCR0
• Bits 7..3 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and always read as zero.
• Bits 2,1,0 – CS02, CS01, CS00: Clock Select0, Bits 2, 1 and 0
The Clock Select0 bits 2,1 and 0 define the prescaling source of Timer/Counter0.
Table 5. Clock 0 Prescale Select
CS02
CS01
CS00
Description
0
0
0
Stop, the Timer/Counter0 is stopped.
0
0
1
CK
0
1
0
CK/8
0
1
1
CK/64
1
0
0
CK/256
1
0
1
CK/1024
1
1
0
External Pin T0, falling edge
1
1
1
External Pin T0, rising edge
The Stop condition provides a Timer Enable/Disable function. The CK down divided modes are scaled directly from the CK
oscillator clock. If the external pin modes are used for Timer/Counter0, transitions on PD4/(T0) will clock the counter even if
the pin is configured as an output. This feature can give the user SW control of the counting.
Timer/Counter0 – TCNT0
Bit
7
$32
MSB
6
5
4
3
2
1
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
LSB
TCNT0
The Timer/Counter0 is realized as an up-counter with read and write access. If the Timer/Counter0 is written and a clock
source is present, the Timer/Counter0 continues counting in the timer clock cycle following the write operation.
20
AT90S1200
AT90S1200
Watchdog Timer
The Watchdog Timer is clocked from a separate on-chip oscillator that runs at 1 MHz. This is the typical value at VCC = 5V.
See characterization data for typical values at other VCC levels. By controlling the Watchdog Timer prescaler, the Watchdog
reset interval can be adjusted, see Table 6 for a detailed description. The WDR (Watchdog Reset) instruction resets the
Watchdog Timer. Eight different clock cycle periods can be selected to determine the maximum period between two WDR
instructions to prevent the Watchdog Timer from resetting the MCU. If the reset period expires without another WDR
instruction, the AT90S1200 resets and executes from the reset vector. For timing details on the Watchdog reset, refer to
page 15.
Figure 20. Watchdog Timer
Watchdog Timer Control Register – WDTCR
Bit
7
6
5
4
3
2
1
0
$21
–
–
–
–
WDE
WDP2
WDP1
WDP0
Read/Write
R
R
R
R
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
WDTCR
• Bits 7..4 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and will always read as zero.
• Bit 3 – WDE: Watchdog Enable
When the WDE is set (one) the Watchdog Timer is enabled, and if the WDE is cleared (zero) the Watchdog Timer function
is disabled.
Bits 2..0 – WDP2..0: Watchdog Timer Prescaler 2, 1 and 0
The WDP2..0 determine the Watchdog Timer prescaling when the Watchdog Timer is enabled. The different prescaling
values and their corresponding timeout periods are shown in Table 6.
21
Table 6. Watchdog Timer Prescale Select
Number of WDT
Oscillator Cycles
Typical Time-out
at VCC = 3.0V
Typical Time-out
at VCC = 5.0V
0
16K cycles
47 ms
15 ms
0
1
32K cycles
94 ms
30 ms
0
1
0
64K cycles
0.19 s
60 ms
0
1
1
128K cycles
0.38 s
0.12 s
1
0
0
256K cycles
0.75 s
0,24 s
1
0
1
512K cycles
1.5 s
0.49 s
1
1
0
1,024K cycles
3.0 s
0.97 s
1
1
1
2,048K cycles
6.0 s
1.9 s
WDP2
WDP1
WDP0
0
0
0
Note:
The frequency of the Watchdog Oscillator is voltage dependent as shown in “Typical Characteristics” on page 47.
The WDR (Watchdog Reset) instruction should always be executed before the Watchdog Timer is enabled. This ensures that
the reset period will be in accordance with the Watchdog Timer prescale settings. If the Watchdog Timer is enabled without
reset, the Watchdog Timer may not start to count from zero.
To avoid unintentional MCU resets, the Watchdog Timer should be disabled or reset before changing the Watchdog Timer
Prescale Select.
EEPROM Read/Write Access
The EEPROM access registers are accessible in the I/O space.
The write access time is in the range of 2.5 - 4 ms, depending on the VCC voltages. A self-timing function, however, lets the
user software detect when the next byte can be written. If the user code contains code that writes the EEPROM, some precaution must be taken. In heavily filtered power supplies, VCC is likely to rise or fall slowly on power-up/down. This causes
the device for some period of time to run at a voltage lower than specified as minimum for the clock frequency used. CPU
operation under these conditions is likely cause the program counter to perform unintentional jumps and eventually execute
the EEPROM write code. To secure EEPROM integrity, the user is advised to use an external under-voltage reset circuit in
this case.
In order to prevent unintentional EEPROM writes, a specific write procedure must be followed. Refer to “EEPROM Control
Register – EECR” on page 23 for details on this.
When the EEPROM is written, the CPU is halted for two clock cycles before the next instruction is executed. When the
EEPROM is read, the CPU is halted for four clock cycles before the next instruction is executed.
EEPROM Address Register – EEAR
Bit
7
6
5
4
3
2
1
0
$1E
–
–
EEAR5
EEAR4
EEAR3
EEAR2
EEAR1
EEAR0
Read/Write
R
R
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
EEAR
• Bit 7,6 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and will always read as zero.
• Bits 5..0 – EEAR5..0: EEPROM Address
The EEPROM Address Register (EEAR5..0) specifies the EEPROM address in the 64-byte EEPROM space. The
EEPROM data bytes are addressed linearly between 0 and 63.
22
AT90S1200
AT90S1200
EEPROM Data Register – EEDR
Bit
7
$1D
MSB
6
5
4
3
2
1
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
LSB
EEDR
• Bits 7..0 – EEDR7..0: EEPROM Data
For the EEPROM write operation, the EEDR register contains the data to be written to the EEPROM in the address given
by the EEAR register. For the EEPROM read operation, the EEDR contains the data read out from the EEPROM at the
address given by EEAR.
EEPROM Control Register – EECR
Bit
7
6
5
4
3
2
1
0
$1C
–
–
–
–
–
–
EEWE
EERE
Read/Write
R
R
R
R
R
R
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
EECR
• Bits 7..2 – Res: Reserved Bits
These bits are reserved bits in the AT90S1200 and will always be read as zero.
• Bit 1 – EEWE: EEPROM Write Enable
The EEPROM Write Enable Signal (EEWE) is the write strobe to the EEPROM. When address and data are correctly set
up, the EEWE bit must be set to write the value into the EEPROM. When the write access time (typically 2.5 ms at VCC =
5V and 4 ms at VCC = 2.7V) has elapsed, the EEWE bit is cleared (zero) by hardware. The user software can poll this bit
and wait for a zero before writing the next byte. When EEWE has been set, the CPU is halted for two cycles before the next
instruction is executed.
• Bit 0 – EERE: EEPROM Read Enable
The EEPROM Read Enable Signal (EERE) is the read strobe to the EEPROM. When the correct address is set up in the
EEAR register, the EERE bit must be set. When the EERE bit is cleared (zero) by hardware, requested data is found in the
EEDR register. The EEPROM read access takes one instruction and there is no need to poll the EERE bit. When EERE
has been set, the CPU is halted for four cycles before the next instruction is executed.
Caution: If an interrupt routine accessing the EEPROM is interrupting another EEPROM access, the EEAR or EEDR register will be modified, causing the interrupted EEPROM access to fail. It is recommended to have the global interrupt flag
cleared during EEPROM write operation to avoid these problems.
Prevent EEPROM Corruption
During periods of low VCC, the EEPROM data can be corrupted because the supply voltage is too low for the CPU and the
EEPROM to operate properly. These issues are the same as for board-level systems using the EEPROM, and the same
design solutions should be applied.
An EEPROM data corruption can be caused by two situations when the voltage is too low. First, a regular write sequence
to the EEPROM requires a minimum voltage to operate correctly. Secondly, the CPU itself can execute instructions incorrectly, if the supply voltage for executing instructions is too low.
EEPROM data corruption can easily be avoided by following these design recommendations (one is sufficient):
1. Keep the AVR RESET active (low) during periods of insufficient power supply voltage. This is best done by an external low VCC Reset Protection circuit, often referred to as a Brown-out Detector (BOD). Please refer to application
note AVR 180 for design considerations regarding power-on reset and low-voltage detection.
2. Keep the AVR core in Power-down Sleep Mode during periods of low VCC. This will prevent the CPU from attempting
to decode and execute instructions, effectively protecting the EEPROM registers from unintentional writes.
3. Store constants in Flash memory if the ability to change memory contents from software is not required. Flash
memory cannot be updated by the CPU, and will not be subject to corruption.
23
Analog Comparator
The Analog Comparator compares the input values on the positive input PB0 (AIN0) and the negative input PB1 (AIN1).
When the voltage on the positive input PB0 (AIN0) is higher than the voltage on the negative input PB1 (AIN1), the Analog
Comparator Output (ACO) is set (one). The comparator’s output can be set to trigger the Analog Comparator interrupt. The
user can select interrupt triggering on comparator output rise, fall or toggle. A block diagram of the comparator and its surrounding logic is shown in Figure 21.
Figure 21. Analog Comparator Block Diagram
Analog Comparator Control and Status Register – ACSR
Bit
7
6
5
4
3
2
1
0
$08
ACD
–
ACO
ACI
ACIE
–
ACIS1
ACIS0
Read/Write
R/W
R
R
R/W
R/W
R
R/W
R/W
Initial value
0
0
N/A
0
0
0
0
0
ACSR
• Bit 7 – ACD: Analog Comparator Disable
When this bit is set (one), the power to the Analog Comparator is switched off. This bit can be set at any time to turn off the
analog comparator. This will reduce power consumption in Active and Idle modes. When changing the ACD bit, the Analog
Comparator Interrupt must be disabled by clearing the ACIE bit in ACSR. Otherwise, an interrupt can occur when the bit is
changed.
• Bit 6 – Res: Reserved Bit
This bit is a reserved bit in the AT90S1200 and will always read as zero.
• Bit 5 – ACO: Analog Comparator Output
ACO is directly connected to the comparator output.
• Bit 4 – ACI: Analog Comparator Interrupt Flag
This bit is set (one) when a comparator output event triggers the interrupt mode defined by ACIS1 and ACIS0. The Analog
Comparator Interrupt routine is executed if the ACIE bit is set (one) and the I-bit in SREG is set (one). ACI is cleared by
hardware when executing the corresponding interrupt handling vector. Alternatively, ACI is cleared by writing a logic one to
the flag. Observe however, that if another bit in this register is modified using the SBI or CBI instruction, ACI will be cleared
if it has become set before the operation.
• Bit 3 – ACIE: Analog Comparator Interrupt Enable
When the ACIE bit is set (one) and the I-bit in the Status Register is set (one), the analog comparator interrupt is activated.
When cleared (zero), the interrupt is disabled.
• Bit 2 – Res: Reserved Bit
This bit is a reserved bit in the AT90S1200 and will always read as zero.
24
AT90S1200
AT90S1200
• Bits 1,0 – ACIS1, ACIS0: Analog Comparator Interrupt Mode Select
These bits determine which comparator events trigger the Analog Comparator Interrupt. The different settings are shown in
Table 7.
Table 7. ACIS1/ACIS0 Settings
ACIS1
ACIS0
0
0
Comparator Interrupt on Output Toggle
0
1
Reserved
1
0
Comparator Interrupt on Falling Output Edge
1
1
Comparator Interrupt on Rising Output Edge
Note:
Interrupt Mode
When changing the ACIS1/ACIS0 bits, the Analog Comparator Interrupt must be disabled by clearing its Interrupt Enable bit in
the ACSR register. Otherwise, an interrupt can occur when the bits are changed.
I/O Ports
All AVR ports have true read-modify-write functionality when used as general digital I/O ports. This means that the direction
of one port pin can be changed without unintentionally changing the direction of any other pin with the SBI and CBI instructions. The same applies for changing drive value (if configured as output) or enabling/disabling of pull-up resistors (if
configured as input).
Port B
Port B is an 8-bit bi-directional I/O port.
Three I/O memory address locations are allocated for the Port B, one each for the Data Register – PORTB ($18), Data
Direction Register – DDRB ($17) and the Port B Input Pins – PINB ($16). The Port B Input Pins address is read-only, while
the Data Register and the Data Direction Register are read/write.
All port pins have individually selectable pull-up resistors. The Port B output buffers can sink 20 mA and thus drive LED displays directly. When pins PB0 to PB7 are used as inputs and are externally pulled low, they will source current if the
internal pull-up resistors are activated.
The Port B pins with alternate functions are shown in Table 8.
Table 8. Port B Pin Alternate Functions
Port Pin
Alternate Functions
PB0
AIN0 (Analog comparator positive input)
PB1
AIN1 (Analog comparator negative input)
PB5
MOSI (Data input line for memory downloading)
PB6
MISO (Data output line for memory uploading)
PB7
SCK (Serial clock input)
When the pins are used for the alternate function, the DDRB and PORTB register has to be set according to the alternate
function description.
25
Port B Data Register – PORTB
Bit
7
6
5
4
3
2
1
0
$18
PORTB7
PORTB6
PORTB5
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
PORTB
Port B Data Direction Register – DDRB
Bit
7
6
5
4
3
2
1
0
$17
DDB7
DDB6
DDB5
DDB4
DDB3
DDB2
DDB1
DDB0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
DDRB
Port B Input Pin Address – PINB
Bit
7
6
5
4
3
2
1
0
$16
PINB7
PINB6
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
Read/Write
R
R
R
R
R
R
R
R
Initial value
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
PINB
The Port B Input Pins address (PINB) is not a register, and this address enables access to the physical value on each
Port B pin. When reading PORTB, the Port B Data Latch is read, and when reading PINB, the logical values present on the
pins are read.
Port B as General Digital I/O
All eight pins in Port B have equal functionality when used as digital I/O pins.
PBn, General I/O pin: The DDBn bit in the DDRB register selects the direction of this pin, if DDBn is set (one), PBn is configured as an output pin. If DDBn is cleared (zero), PBn is configured as an input pin. If PORTBn is set (one) and the pin is
configured as an input pin, the MOS pull-up resistor is activated. To switch the pull-up resistor off, PORTBn has to be
cleared (zero) or the pin has to be configured as an output pin. The Port B pins are tri-stated when a reset condition
becomes active, even if the clock is not active.
Table 9. DDBn Effect on Port B Pins
DDBn
PORTBn
I/O
Pull-up
0
0
Input
No
Tri-state (High-Z)
0
1
Input
Yes
PBn will source current if ext. pulled low.
1
0
Output
No
Push-pull Zero Output
1
Output
No
Push-pull One Output
1
Note:
n: 7,6...0, pin number.
Alternate Functions of Port B
The alternate pin functions of Port B are:
• SCK – Port B, Bit 7
SCK, Clock input pin for memory up/downloading.
• MISO – Port B, Bit 6
MISO, Data output pin for memory uploading.
• MOSI – Port B, Bit 5
MOSI, Data input pin for memory downloading.
26
AT90S1200
Comment
AT90S1200
• AIN1 – Port B, Bit 1
AIN1, Analog Comparator Negative Input. When configured as an input (DDB1 is cleared [zero]) and with the internal MOS
pull-up resistor switched off (PB1 is cleared [zero]), this pin also serves as the negative input of the on-chip Analog
Comparator.
• AIN0 – Port B, Bit 0
AIN0, Analog Comparator Positive Input. When configured as an input (DDB0 is cleared [zero]) and with the internal MOS
pull-up resistor switched off (PB0 is cleared [zero]), this pin also serves as the positive input of the on-chip Analog
Comparator.
Port B Schematics
Note that all port pins are synchronized. The synchronization latches are, however, not shown in the figures.
Figure 22. Port B Schematic Diagram (Pins PB0 and PB1)
27
Figure 23. Port B Schematic Diagram (Pins PB2, PB3 and PB4)
2,
Figure 24. Port B Schematic Diagram (Pin PB5)
28
AT90S1200
AT90S1200
Figure 25. Port B Schematic Diagram (Pin PB6)
Figure 26. Port B Schematic Diagram (Pin PB7)
29
Port D
Three I/O memory address locations are allocated for Port D, one each for the Data Register – PORTD ($12), Data Direction Register – DDRD ($11) and the Port D Input Pins – PIND ($10). The Port D Input Pins address is read-only, while the
Data Register and the Data Direction Register are read/write.
Port D has seven bi-directional I/O pins with internal pull-up resistors, PD6..PD0. The Port D output buffers can sink 20 mA.
As inputs, Port D pins that are externally pulled low will source current if the pull-up resistors are activated.
Some Port D pins have alternate functions as shown in Table 10.
Table 10. Port D Pin Alternate Functions
Port Pin
Alternate Function
PD2
INT0 (External interrupt 0 input)
PD4
T0 (Timer/Counter 0 external input)
Port D Data Register – PORTD
Bit
7
6
5
4
3
2
1
0
$12
–
PORTD6
PORTD5
PORTD4
PORTD3
PORTD2
PORTD1
PORTD0
Read/Write
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
PORTD
Port D Data Direction Register – DDRD
Bit
7
6
5
4
3
2
1
0
$11
–
DDD6
DDD5
DDD4
DDD3
DDD2
DDD1
DDD0
Read/Write
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
DDRD
Port D Input Pins Address – PIND
Bit
7
6
5
4
3
2
1
0
$10
–
PIND6
PIND5
PIND4
PIND3
PIND2
PIND1
PIND0
Read/Write
R
R
R
R
R
R
R
R
Initial value
0
N/A
N/A
N/A
N/A
N/A
N/A
N/A
PIND
The Port D Input Pins address (PIND) is not a register, and this address enables access to the physical value on each
Port D pin. When reading PORTD, the Port D Data Latch is read; and when reading PIND, the logical values present on the
pins are read.
Port D as General Digital I/O
PDn, general I/O pin: The DDDn bit in the DDRD register selects the direction of this pin. If DDDn is set (one), PDn is configured as an output pin. If DDDn is cleared (zero), PDn is configured as an input pin. If PORTDn is set (one) when DDDn
is configured as an input pin, the MOS pull-up resistor is activated. To switch the pull-up resistor off, the PORTDn bit has to
be cleared (zero) or the pin has to be configured as an output pin. The Port D pins are tri-stated when a reset condition
becomes active, even if the clock is not active.
Table 11. DDDn Bits’ Effect on Port D Pins
DDDn
PORTDn
I/O
Pull-up
0
0
Input
No
Tri-state (High-Z)
0
1
Input
Yes
PDn will source current if ext. pulled low.
1
0
Output
No
Push-pull Zero Output
1
1
Output
No
Push-pull One Output
Note:
30
n: 6…0, pin number.
AT90S1200
Comment
AT90S1200
Alternate Functions for Port D
The alternate functions of Port D are:
• T0 – Port D, Bit 4
T0, Timer/Counter0 clock source. See the timer description for further details.
• INT0 – Port D, Bit 2
INT0, External Interrupt source 0. See the interrupt description for further details.
Port D Schematics
Note that all port pins are synchronized. The synchronization latches are, however, not shown in the figures.
Figure 27. Port D Schematic Diagram (Pins PD0, PD1, PD3, PD5 and PD6)
31
Figure 28. Port D Schematic Diagram (Pin PD2)
Figure 29. Port D Schematic Diagram (Pin PD4)
RD
MOS
PULLUP
RESET
Q
R
D
DDD4
WD
RESET
R
Q
D
PORTD4
PD4
C
RL
WP
RP
WP:
WD:
RL:
RP:
RD:
WRITE PORTD
WRITE DDRD
READ PORTD LATCH
READ PORTD PIN
READ DDRD
SENSE CONTROL
CS02
32
AT90S1200
CS01
CS00
TIMER0 CLOCK
SOURCE MUX
DATA BUS
C
AT90S1200
Memory Programming
Program and Data Memory Lock Bits
The AT90S1200 MCU provides two Lock bits that can be left unprogrammed (“1”) or can be programmed (“0”) to obtain the
additional features listed in Table 12. The Lock bits can only be erased with the Chip Erase command.
Table 12. Lock Bit Protection Modes
Memory Lock Bits
Mode
LB1
LB2
1
1
1
No memory lock features enabled.
2
0
1
Further programming of the Flash and EEPROM is disabled.(1)
3
0
0
Same as mode 2, and verify is also disabled.
Note:
Protection Type
1. In Parallel Mode, further programming of the Fuse bits are also disabled. Program the Fuse bits before programming the
Lock bits.
Fuse Bits
The AT90S1200 has two Fuse bits: SPIEN and RCEN.
• When the SPIEN Fuse bit is programmed (“0”), Serial Program Downloading is enabled. Default value is programmed
(“0”).
• When the RCEN Fuse bit is programmed (“0”), MCU clocking from the internal RC oscillator is selected. Default value is
erased (“1”). Parts with this bit pre-programmed (“0”) can be delivered on demand.
• The Fuse bits are not accessible in Serial Programming Mode. The status of the Fuse bits is not affected by Chip Erase.
Signature Bytes
All Atmel microcontrollers have a 3-byte signature code that identifies the device. This code can be read in both Serial and
Parallel modes. The three bytes reside in a separate address space.
For the AT90S1200 they are:
1. $00: $1E (indicates manufactured by Atmel)
2. $01: $90 (indicates 1 Kb Flash memory)
3. $02: $01 (indicates AT90S1200 device when $01 is $90)
Note:
When both Lock bits are programmed (lock mode 3), the signature bytes cannot be read in Serial Mode. Reading the
signature bytes will return: $00, $01 and $02.
Programming the Flash and EEPROM
Atmel’s AT90S1200 offers 1K byte of in-system reprogrammable Flash program memory and 64 bytes of EEPROM data
memory.
The AT90S1200 is normally shipped with the on-chip Flash program memory and EEPROM data memory arrays in the
erased state (i.e., contents = $FF) and ready to be programmed. This device supports a high-voltage (12V) Parallel Programming Mode and a low-voltage Serial Programming Mode. The +12V is used for programming enable only, and no
current of significance is drawn by this pin. The Serial Programming Mode provides a convenient way to download program
and data into the AT90S1200 inside the user’s system.
The program and data memory arrays on the AT90S1200 are programmed byte-by-byte in either programming mode. For
the EEPROM, an auto-erase cycle is provided within the self-timed write instruction in the Serial Programming Mode. During programming, the supply voltage must be in accordance with Table 13.
33
Table 13. Supply Voltage during Programming
Part
Serial Programming
Parallel Programming
AT90S1200
2.7 - 6.0V
4.5 - 5.5V
Parallel Programming
This section describes how to parallel program and verify Flash program memory, EEPROM data memory, Lock bits and
Fuse bits in the AT90S1200.
Figure 30. Parallel Programming
Signal Names
In this section, some pins of the AT90S1200 are referenced by signal names describing their function during parallel
programming rather than their pin names, see Figure 30 and Table 14. Pins not described in Table 14 are referenced by
pin names.
The XA1/XA0 pins determines the action executed when the XTAL1 pin is given a positive pulse. The coding is shown in
Table 15.
When pulsing WR or OE, the command loaded determines the action executed. The command is a byte where the
different bits are assigned functions as shown in Table 16.
Table 14. Pin Name Mapping
34
Signal Name in
Programming Mode
Pin Name
I/O
Function
RDY/BSY
PD1
O
0: Device is busy programming, 1: Device is ready for new command
OE
PD2
I
Output Enable (Active low)
WR
PD3
I
Write Pulse (Active low)
BS
PD4
I
Byte Select (“0” selects low byte, “1” selects high byte)
XA0
PD5
I
XTAL Action Bit 0
XA1
PD6
I
XTAL Action Bit 1
DATA
PB0-7
I/O
AT90S1200
Bi-directional Data Bus (Output when OE is low)
AT90S1200
.
Table 15. XA1 and XA0 Coding
XA1
XA0
Action when XTAL1 is Pulsed
0
0
Load Flash or EEPROM Address (High or low address byte for Flash determined by BS)
0
1
Load Data (High or low data byte for Flash determined by BS)
1
0
Load Command
1
1
No Action, Idle
Table 16. Command Byte Coding
Command Byte
Command Executed
1000 0000
Chip Erase
0100 0000
Write Fuse Bits
0010 0000
Write Lock Bits
0001 0000
Write Flash
0001 0001
Write EEPROM
0000 1000
Read Signature Bytes
0000 0100
Read Fuse and Lock Bits
0000 0010
Read Flash
0000 0011
Read EEPROM
Enter Programming Mode
The following algorithm puts the device in Parallel Programming Mode:
1. Apply supply voltage according to Table 13, between VCC and GND.
2. Set the RESET and BS pin to “0” and wait at least 100 ns.
3. Apply 11.5 - 12.5V to RESET. Any activity on BS within 100 ns after +12V has been applied to RESET, will cause
the device to fail entering Programming Mode.
Chip Erase
The Chip Erase command will erase the Flash and EEPROM memories, and the Lock bits. The Lock bits are not reset until
the Flash and EEPROM have been completely erased. The Fuse bits are not changed. Chip Erase must be performed
before the Flash or EEPROM is reprogrammed.
Load Command “Chip Erase”
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS to “0”.
3. Set DATA to “1000 0000”. This is the command for Chip Erase.
4. Give XTAL1 a positive pulse. This loads the command.
5. Give WR a tWLWH_CE wide negative pulse to execute Chip Erase, tWLWH_CE is found in Table 17. Chip Erase does not
generate any activity on the RDY/BSY pin.
35
Programming the Flash
A: Load Command “Write Flash”
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS to “0”.
3. Set DATA to “0001 0000”. This is the command for Write Flash.
4. Give XTAL1 a positive pulse. This loads the command.
B: Load Address High Byte
1. Set XA1, XA0 to “00”. This enables address loading.
2. Set BS to “1”. This selects high byte.
3. Set DATA = Address high byte ($00 - $01).
4. Give XTAL1 a positive pulse. This loads the address high byte.
C: Load Address Low Byte
1. Set XA1, XA0 to “00”. This enables address loading.
2. Set BS to “0”. This selects low byte.
3. Set DATA = Address low byte ($00 - $FF).
4. Give XTAL1 a positive pulse. This loads the address low byte.
D: Load Data Low Byte
1. Set XA1, XA0 to “01”. This enables data loading.
2. Set DATA = Data low byte ($00 - $FF).
3. Give XTAL1 a positive pulse. This loads the data low byte.
E: Write Data Low Byte
1. Set BS to “0”. This selects low data.
2. Give WR a negative pulse. This starts programming of the data byte. RDY/BSY goes low.
3. Wait until RDY/BSY goes high to program the next byte.
(See Figure 31 for signal waveforms.)
F: Load Data High Byte
1. Set XA1, XA0 to “01”. This enables data loading.
2. Set DATA = Data high byte ($00 - $FF).
3. Give XTAL1 a positive pulse. This loads the data high byte.
G: Write Data High Byte
1. Set BS to “1”. This selects high data.
2. Give WR a negative pulse. This starts programming of the data byte. RDY/BSY goes low.
3. Wait until RDY/BSY goes high to program the next byte.
(See Figure 32 for signal waveforms.)
The loaded command and address are retained in the device during programming. For efficient programming, the following
should be considered:
• The command needs only be loaded once when writing or reading multiple memory locations.
• Address high byte needs only be loaded before programming a new 256-word page in the Flash.
• Skip writing the data value $FF; that is, the contents of the entire Flash and EEPROM after a Chip Erase.
These considerations also apply to EEPROM programming and Flash, EEPROM and signature byte reading.
36
AT90S1200
AT90S1200
Figure 31. Programming the Flash Waveforms
DATA
$10
ADDR. HIGH
ADDR.LOW
DATA LOW
XA1
XA0
BS
XTAL1
WR
RDY/BSY
RESET
12V
OE
Figure 32. Programming the Flash Waveforms (Continued)
DATA
DATA HIGH
XA1
XA0
BS
XTAL1
WR
RDY/BSY
RESET
+12V
OE
Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to “Programming the Flash” for details on command and
address loading):
1. A: Load Command “0000 0010”.
2. B: Load Address High Byte ($00 - $01).
3. C: Load Address Low Byte ($00 - $FF).
4. Set OE to “0”, and BS to “0”. The Flash word low byte can now be read at DATA.
5. Set BS to “1”. The Flash word high byte can now be read from DATA.
6. Set OE to “1”.
37
Programming the EEPROM
The programming algorithm for the EEPROM data memory is as follows (refer to “Programming the Flash” for details on
command, address and data loading):
1. A: Load Command “0001 0001”.
2. C: Load Address Low Byte ($00 - $3F).
3. D: Load Data Low Byte ($00 - $FF).
4. E: Write Data Low Byte.
Reading the EEPROM
The algorithm for reading the EEPROM memory is as follows (refer to “Programming the Flash” for details on command
and address loading):
1. A: Load Command “0000 0011”.
2. C: Load Address Low Byte ($00 - $3F).
3. Set OE to “0”, and BS to “0”. The EEPROM data byte can now be read at DATA.
4. Set OE to “1”.
Programming the Fuse Bits
The algorithm for programming the Fuse bits is as follows (refer to “Programming the Flash” for details on command and
data loading):
1. A: Load Command “0100 0000”.
2. D: Load Data Low Byte. Bit n = “0” programs and bit n = “1” erases the Fuse bit.
Bit 5 = SPIEN Fuse
Bit 0 = RCEN Fuse
Bit 7-6,4-1 = “1”. These bits are reserved and should be left unprogrammed (“1”).
3. Give WR a tWLWH_PFB wide negative pulse to execute the programming; tWLWH_PFB is found in Table 17. Programming
the Fuse bits does not generate any activity on the RDY/BSY pin.
Programming the Lock Bits
The algorithm for programming the Lock bits is as follows (refer to “Programming the Flash” for details on command and
data loading):
1. A: Load Command “0010 0000”.
2. D: Load Data Low Byte. Bit n = “0” programs the Lock bit.
Bit 2 = Lock Bit2
Bit 1 = Lock Bit1
Bit 7-3,0 = “1”. These bits are reserved and should be left unprogrammed (“1”).
3. E: Write Data Low Byte.
The Lock bits can only be cleared by executing Chip Erase.
38
AT90S1200
AT90S1200
Reading the Fuse and Lock Bits
The algorithm for reading the Fuse and Lock bits is as follows (refer to “Programming the Flash” on page 36 for details on
command loading):
1. A: Load Command “0000 0100”.
2. Set OE to “0”, and BS to “1”. The status of Fuse and Lock bits can now be read at DATA (“0” means programmed).
Bit 7 = Lock Bit1
Bit 6 = Lock Bit2
Bit 5 = SPIEN Fuse
Bit 0 = RCEN Fuse
3. Set OE to “1”.
Observe especially that BS needs to be set to “1”.
Reading the Signature Bytes
The algorithm for reading the signature bytes is as follows (refer to “Programming the Flash” on page 36 for details on command and address loading):
1. A: Load Command “0000 1000”.
2. C: Load Address Low Byte ($00 - $02).
Set OE to “0”, and BS to “0”. The selected signature byte can now be read at DATA.
3. Set OE to “1”.
Parallel Programming Characteristics
Figure 33. Parallel Programming Timing
tXLWL
tXHXL
XTAL1
tDVXH
tXLDX tBVWL
tWLWH
WR
tWHRL
tRHBX
Write
Data & Contol
(DATA, XA0/1, BS)
RDY/BSY
OE
DATA
tXLOL
tOLDV
tOHDZ
Read
tWLRH
39
Table 17. Parallel Programming Characteristics, TA = 25°C ± 10%, VCC = 5V ± 10%
Symbol
Parameter
Min
VPP
Programming Enable Voltage
11.5
IPP
Programming Enable Current
tDVXH
Data and Control Setup before XTAL1 High
67.0
ns
tXHXL
XTAL1 Pulse Width High
67.0
ns
tXLDX
Data and Control Hold after XTAL1 Low
67.0
ns
tXLWL
XTAL1 Low to WR Low
67.0
ns
tBVWL
BS Valid to WR Low
67.0
ns
tRHBX
BS Hold after RDY/BSY High
67.0
ns
67.0
ns
(1)
tWLWH
WR Pulse Width Low
tWHRL
WR High to RDY/BSY Low(2)
tWLRH
WR Low to RDY/BSY High(2)
0.5
tXLOL
XTAL1 Low to OE Low
67.0
tOLDV
OE Low to DATA Valid
tOHDZ
OE High to DATA Tri-stated
tWLWH_CE
WR Pulse Width Low for Chip Erase
5.0
tWLWH_PFB
WR Pulse Width Low for Programming the Fuse
Bits
1.0
Notes:
Typ
Max
Units
12.5
V
250.0
µA
20.0
0.7
ns
0.9
ms
ns
20.0
ns
20.0
ns
10.0
15.0
ms
1.5
1.8
ms
1. Use tWLWH_CE for chip erase and tWLWH_PFB for programming the Fuse bits.
2. If tWLWH is held longer than tWLRH, no RDY/BSY pulse will be seen.
Serial Downloading
Both the program and data memory arrays can be programmed using the SPI bus while RESET is pulled to GND. The
serial interface consists of pins SCK, MOSI (input) and MISO (output) (see Figure 34). After RESET is set low, the Programming Enable instruction needs to be executed first before program/erase instructions can be executed.
Figure 34. Serial Programming and Verify
AT90S1200
GND
RESET
2.7 - 6.0V
VCC
PB7 (SCK)
PB6 (MISO)
PB5 (MOSI)
XTAL2
XTAL1
GND
40
AT90S1200
CLOCK IN
DATA OUT
INSTR. IN
AT90S1200
For the EEPROM, an auto-erase cycle is provided within the self-timed write instruction and there is no need to first
execute the Chip Erase instruction. The Chip Erase instruction turns the content of every memory location in both the
Program and EEPROM arrays into $FF.
The program and EEPROM memory arrays have separate address spaces: $0000 to $01FF for Flash program memory
and $000 to $03F for EEPROM data memory.
Either an external system clock is supplied at pin XTAL1 or a crystal needs to be connected across pins XTAL1 and
XTAL2. The minimum low and high periods for the serial clock (SCK) input are defined as follows:
Low: > 1 XTAL1 clock cycle
High: > 4 XTAL1 clock cycles
Serial Programming Algorithm
When writing serial data to the AT90S1200, data is clocked on the rising edge of SCK.
When reading data from the AT90S1200, data is clocked on the falling edge of SCK. See Figure 35 and Table 20 for timing
details.
To program and verify the AT90S1200 in the Serial Programming Mode, the following sequence is recommended (See
4-byte instruction formats in Table 17):
1. Power-up sequence:
Apply power between VCC and GND while RESET and SCK are set to “0”. If a crystal is not connected across pins
XTAL1 and XTAL2 or the device is not running from the internal RC oscillator, apply a clock signal to the XTAL1 pin. If
the programmer can not guarantee that SCK is held low during power-up, RESET must be given a positive pulse after
SCK has been set to “0”.
2. Wait for at least 20 ms and enable serial programming by sending the Programming Enable serial instruction to the
MOSI (PB5) pin.
3. If a Chip Erase is performed (must be done to erase the Flash), wait tWD_ERASE after the instruction, give RESET a
positive pulse, and start over from step 2. See Table 21 on page 43 for tWD_ERASE value.
4. The Flash or EEPROM array is programmed one byte at a time by supplying the address and data together with the
appropriate Write instruction. An EEPROM memory location is first automatically erased before new data is written.
Wait tWD_PROG after transmitting the instruction. In an erased device, no $FFs in the data file(s) needs to be programmed. See Table 22 on page 43 for tWD_PROG value.
5. Any memory location can be verified by using the Read instruction which returns the content at the selected
address at the serial output MISO (PB6) pin.
At the end of the programming session, RESET can be set high to commence normal operation.
6. Power-off sequence (if needed):
Set XTAL1 to “0” (if a crystal is not used or the device is running from the internal RC oscillator).
Set RESET to “1”.
Turn VCC power off.
Data Polling EEPROM
When a byte is being programmed into the EEPROM, reading the address location being programmed will give the value
P1 until the auto-erase is finished, and then the value P2. See Table 18 for P1 and P2 values.
At the time the device is ready for a new EEPROM byte, the programmed value will read correctly. This is used to determine when the next byte can be written. This will not work for the values P1 and P2, so when programming these values,
the user will have to wait for at least the prescribed time tWD_PROG before programming the next byte. See Table 22 for
tWD_PROG value. As a chip-erased device contains $FF in all locations, programming of addresses that are meant to contain
$FF can be skipped. This does not apply if the EEPROM is reprogrammed without first chip-erasing the device.
41
Table 18. Read Back Value during EEPROM Polling
Part
P1
P2
AT90S1200
$00
$FF
Data Polling Flash
When a byte is being programmed into the Flash, reading the address location being programmed will give the value $FF.
At the time the device is ready for a new byte, the programmed value will read correctly. This is used to determine when the
next byte can be written. This will not work for the value $FF, so when programming this value, the user will have to wait for
at least tWD_PROG before programming the next byte. As a chip-erased device contains $FF in all locations, programming of
addresses that are meant to contain $FF, can be skipped.
Figure 35. Serial Programming Waveforms
Table 19. Serial Programming Instruction Set for AT90S1200
Instruction Format
Instruction
Byte 1
Byte 2
Byte 3
Byte4
Operation
Programming
Enable
1010 1100
0101 0011
xxxx xxxx
xxxx xxxx
Enable serial programming while RESET is low.
Chip Erase
1010 1100
100x xxxx
xxxx xxxx
xxxx xxxx
Chip erase both Flash and EEPROM memory
arrays.
Read Program
Memory
0010 H000
0000 000a
bbbb bbbb
oooo oooo
Read H (high or low) byte o from program memory
at word address a:b.
Write Program
Memory
0100 H000
0000 000a
bbbb bbbb
iiii iiii
Write H (high or low) byte i to program memory at
word address a:b.
Read EEPROM
Memory
1010 0000
0000 0000
00bb bbbb
oooo oooo
Read data o from EEPROM memory at address b.
Write EEPROM
Memory
1100 0000
0000 0000
00bb bbbb
iiii iiii
Write data i to EEPROM memory at address b.
Write Lock Bits
1010 1100
1111 1211
xxxx xxxx
xxxx xxxx
Write Lock bits. Set bits 1,2 = “0” to program Lock
bits.
Read Signature
Byte
0011 0000
xxxx xxxx
xxxx xxbb
oooo oooo
Read signature byte o from address b.(1)
Note:
a = address high bits
b = address low bits
H = 0 – Low byte, 1 – High byte
o = data out
i = data in
x = don’t care
1 = Lock Bit 1
2 = Lock Bit 2
Note:
1. The signature bytes are not readable in lock mode 3 (i.e., both Lock bits programmed).
42
AT90S1200
AT90S1200
Serial Programming Characteristics
Figure 36. Serial Programming Timing
MOSI
tSHOX
tOVSH
SCK
tSLSH
tSHSL
MISO
tSLIV
Table 20. Serial Programming Characteristics, TA = -40°C to 85°C, VCC = 2.7 - 6.0V (unless otherwise noted)
Symbol
Parameter
1/tCLCL
Oscillator Frequency (VCC = 2.7 - 4.0V)
tCLCL
1/tCLCL
Min
0
Oscillator Period (VCC = 2.7 - 4.0V)
Oscillator Period (VCC = 4.0 - 6.0V)
tSHSL
Max
Units
4.0
MHz
250.0
Oscillator Frequency (VCC = 4.0 - 6.0V)
tCLCL
Typ
ns
0
12.0
MHz
83.3
ns
SCK Pulse Width High
4.0 tCLCL
ns
tSLSH
SCK Pulse Width Low
tCLCL
ns
tOVSH
MOSI Setup to SCK High
1.25 tCLCL
ns
tSHOX
MOSI Hold after SCK High
2.5 tCLCL
ns
tSLIV
SCK Low to MISO Valid
10.0
16.0
32.0
ns
Table 21. Minimum Wait Delay after the Chip Erase Instruction
Symbol
3.2V
3.6V
4.0V
5.0V
tWD_ERASE
18 ms
14 ms
12 ms
8 ms
Table 22. Minimum Wait Delay after Writing a Flash or EEPROM Location
Symbol
3.2V
3.6V
4.0V
5.0V
tWD_PROG
9 ms
7 ms
6 ms
4 ms
43
Electrical Characteristics
Absolute Maximum Ratings*
Operating Temperature.................................. -55°C to +125°C
Storage Temperature ..................................... -65°C to +150°C
Voltage on Any Pin Except RESET
with Respect to Ground ...............................-1.0V to VCC+0.5V
Voltage on RESET with Respect to Ground ....-1.0V to +13.0V
Maximum Operating Voltage ............................................ 6.6V
DC Current per I/O Pin ............................................... 40.0 mA
DC Current VCC and GND Pins................................ 200.0 mA
44
AT90S1200
*NOTICE:
Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and
functional operation of the device at these or
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect device
reliability.
AT90S1200
DC Characteristics
TA = -40°C to 85°C, VCC = 2.7V to 6.0V (unless otherwise noted)
Symbol
VIL
VIL1
Parameter
Condition
Input Low Voltage
(Except XTAL1)
Input Low Voltage
(XTAL1)
Min
Typ
Max
Units
0.3 VCC
(1)
V
0.3 VCC
(1)
V
(2)
VCC + 0.5
V
-0.5
-0.5
VIH
Input High Voltage
(Except XTAL1, RESET)
0.6 VCC
VIH1
Input High Voltage
(XTAL1)
0.7 VCC(2)
VCC + 0.5
V
VCC(2)
VCC + 0.5
V
0.6
0.5
V
V
VIH2
Input High Voltage
(RESET)
(3)
0.85
IOL = 20 mA, VCC = 5V
IOL = 10 mA, VCC = 3V
VOL
Output Low Voltage
(Ports B, D)
VOH
Output High Voltage(4)
(Ports B, D)
IOH = -3 mA, VCC = 5V
IOH = -1.5 mA, VCC = 3V
IIL
Input Leakage
Current I/O pin
VCC = 6V, pin low
(absolute value)
8.0
µA
IIH
Input Leakage
Current I/O pin
VCC = 6V, pin high
(absolute value)
980.0
nA
RRST
Reset Pull-up Resistor
100.0
500.0
kΩ
RI/O
I/O Pin Pull-up Resistor
35.0
120.0
kΩ
mA
Power Supply Current
Active Mode, VCC = 3V,
4 MHz
3.0
ICC
Idle Mode VCC = 3V, 4 MHz
1.0
mA
V
V
WDT enabled, VCC = 3V
9.0
15.0
µA
WDT disabled, VCC = 3V
<1.0
2.0
µA
40.0
mV
50.0
nA
ICC
Power-down Mode(5)
VACIO
Analog Comparator
Input Offset Voltage
VCC = 5V
Vin = VCC/ 2
IACLK
Analog Comparator
Input Leakage Current
VCC = 5V
Vin = VCC/ 2
tACPD
Analog Comparator
Propagation Delay
VCC = 2.7V
VCC = 4.0V
Notes:
4.3
2.3
-50.0
750.0
500.0
ns
1. “Max” means the highest value where the pin is guaranteed to be read as low.
2. “Min” means the lowest value where the pin is guaranteed to be read as high.
3. Although each I/O port can sink more than the test conditions (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOL, for all ports, should not exceed 200 mA.
2] The sum of all IOL, for port D0 - D5 and XTAL2, should not exceed 100 mA.
3] The sum of all IOL, for ports B0 - B7 and D6, should not exceed 100 mA.
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test condition.
4. Although each I/O port can source more than the test conditions (3 mA at VCC = 5V, 1.5 mA at VCC = 3V) under steady state
conditions (non-transient), the following must be observed:
1] The sum of all IOH, for all ports, should not exceed 200 mA.
2] The sum of all IOH, for port D0 - D5 and XTAL2, should not exceed 100 mA.
3] The sum of all IOH, for ports B0 - B7 and D6, should not exceed 100 mA.
If IOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current
greater than the listed test condition.
5. Minimum VCC for power-down is 2V.
45
External Clock Drive Waveforms
Figure 37. External Clock Drive
VIH1
VIL1
External Clock Drive
VCC = 2.7V to 4.0V
VCC = 4.0V to 6.0V
Min
Max
Min
Max
Units
0
4.0
0
12.0
MHz
Symbol
Parameter
1/tCLCL
Oscillator Frequency
tCLCL
Clock Period
250.0
83.3
ns
tCHCX
High Time
100.0
33.3
ns
tCLCX
Low Time
100.0
33.3
ns
tCLCH
Rise Time
1.6
0.5
µs
tCHCL
Fall Time
1.6
0.5
µs
46
AT90S1200
AT90S1200
Typical Characteristics
The following charts show typical behavior. These figures are not tested during manufacturing. All current consumption
measurements are performed with all I/O pins configured as inputs and with internal pull-ups enabled. A sine wave generator with rail-to-rail output is used as clock source.
The power consumption in Power-down Mode is independent of clock selection.
The current consumption is a function of several factors such as: operating voltage, operating frequency, loading of I/O
pins, switching rate of I/O pins, code executed and ambient temperature. The dominating factors are operating voltage and
frequency.
The current drawn from capacitive loaded pins may be estimated (for one pin) as CL • VCC • f where CL = load capacitance,
VCC = operating voltage and f = average switching frequency of I/O pin.
The parts are characterized at frequencies higher than test limits. Parts are not guaranteed to function properly at frequencies higher than the ordering code indicates.
The difference between current consumption in Power-down Mode with Watchdog timer enabled and Power-down Mode
with Watchdog timer disabled represents the differential current drawn by the Watchdog timer.
Figure 38. Active Supply Current vs. Frequency
ACTIVE SUPPLY CURRENT vs. FREQUENCY
TA= 25˚C
I cc(mA)
18
16
Vcc= 6V
14
Vcc= 5.5V
12
Vcc= 5V
10
Vcc= 4.5V
Vcc= 4V
8
Vcc= 3.6V
6
Vcc= 3.3V
Vcc= 3.0V
4
Vcc= 2.7V
2
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Frequency (MHz)
47
Figure 39. Active Supply Current vs. VCC
ACTIVE SUPPLY CURRENT vs. Vcc
FREQUENCY = 4 MHz
10
TA = -40˚C
9
TA = 25˚C
8
7
I cc(mA)
TA = 85˚C
6
5
4
3
2
1
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 40. Active Supply Current vs. VCC, Device Clocked by Internal Oscillator
ACTIVE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY INTERNAL RC OSCILLATOR
7
6
TA = 25˚C
5
I cc(mA)
TA = 85˚C
4
3
2
1
0
2
2.5
3
3.5
4
Vcc(V)
48
AT90S1200
4.5
5
5.5
6
AT90S1200
Figure 41. Idle Supply Current vs. Frequency
IDLE SUPPLY CURRENT vs. FREQUENCY
TA= 25˚C
4.5
Vcc= 6V
4
3.5
Vcc= 5.5V
I cc(mA)
3
Vcc= 5V
2.5
Vcc= 4.5V
2
Vcc= 4V
Vcc= 3.6V
Vcc= 3.3V
Vcc= 3.0V
1.5
1
Vcc= 2.7V
0.5
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Frequency (MHz)
Figure 42. Idle Supply Current vs. VCC
IDLE SUPPLY CURRENT vs. Vcc
FREQUENCY = 4 MHz
2.5
TA = -40˚C
TA = 25˚C
2
I cc(mA)
1.5
TA = 85˚C
1
0.5
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
49
Figure 43. Idle Supply Current vs. VCC, Device Clocked by Internal Oscillator
IDLE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY INTERNAL RC OSCILLATOR
0.4
TA = 25˚C
0.35
0.3
TA = 85˚C
I cc(mA)
0.25
0.2
0.15
0.1
0.05
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 44. Power-down Supply Current vs. VCC, Watchdog Timer Disabled
POWER DOWN SUPPLY CURRENT vs. Vcc
WATCHDOG TIMER DISABLED
1.8
TA = 85˚C
1.6
I cc(µΑ)
1.4
1.2
1
TA = 70˚C
0.8
0.6
0.4
TA = 45˚C
0.2
TA = 25˚C
0
2
2.5
3
3.5
4
Vcc(V)
50
AT90S1200
4.5
5
5.5
6
AT90S1200
Figure 45. Power-down Supply Current vs. VCC, Watchdog Timer Enabled
POWER DOWN SUPPLY CURRENT vs. Vcc
WATCHDOG TIMER ENABLED
140
TA = 25˚C
120
TA = 85˚C
I cc(µΑ)
100
80
60
40
20
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 46. Internal RC Oscillator Frequency vs. VCC
INTERNAL RC OSCILLATOR FREQUENCY vs. Vcc
1600
TA = 25˚C
1400
TA = 85˚C
F RC (KHz)
1200
1000
800
600
400
200
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc (V)
51
Figure 47. Analog Comparator Current vs. VCC
ANALOG COMPARATOR CURRENT vs. Vcc
1.2
1
TA = -40˚C
TA = 25˚C
I cc(mA)
0.8
0.6
TA = 85˚C
0.4
0.2
0
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Note:
Analog comparator offset voltage is measured as absolute offset.
Figure 48. Analog Comparator Offset Voltage vs. Common Mode Voltage
ANALOG COMPARATOR OFFSET VOLTAGE vs.
COMMON MODE VOLTAGE
Vcc = 5V
18
16
TA = 25˚C
Offset Voltage (mV)
14
12
TA = 85˚C
10
8
6
4
2
0
0
0.5
1
1.5
2
2.5
3
Common Mode Voltage (V)
52
AT90S1200
3.5
4
4.5
5
AT90S1200
Figure 49. Analog Comparator Offset Voltage vs. Common Mode Voltage
ANALOG COMPARATOR OFFSET VOLTAGE vs.
Vcc = 2.7V
COMMON MODE VOLTAGE
10
TA = 25˚C
Offset Voltage (mV)
8
6
TA = 85˚C
4
2
0
0
0.5
1
1.5
2
2.5
3
Common Mode Voltage (V)
Figure 50. Analog Comparator Input Leakage Current
ANALOG COMPARATOR INPUT LEAKAGE CURRENT
VCC = 6V
TA = 25˚C
60
50
30
I
ACLK
(nA)
40
20
10
0
-10
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
VIN (V)
Note:
Sink and source capabilities of I/O ports are measured on one pin at a time.
53
Figure 51. Pull-up Resistor Current vs. Input Voltage
PULL-UP RESISTOR CURRENT vs. INPUT VOLTAGE
Vcc = 5V
120
TA = 25˚C
100
TA = 85˚C
I
OP (µA)
80
60
40
20
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
VOP (V)
Figure 52. Pull-up Resistor Current vs. Input Voltage
PULL-UP RESISTOR CURRENT vs. INPUT VOLTAGE
Vcc = 2.7V
30
TA = 25˚C
25
TA = 85˚C
15
I
OP (µA)
20
10
5
0
0
0.5
1
1.5
VOP (V)
54
AT90S1200
2
2.5
3
AT90S1200
Figure 53. I/O Pin Sink Current vs. Output Voltage
I/O PIN SINK CURRENT vs. OUTPUT VOLTAGE
Vcc = 5V
70
TA = 25˚C
60
TA = 85˚C
50
30
I
OL (mA)
40
20
10
0
0
0.5
1
1.5
2
2.5
3
VOL (V)
Figure 54. I/O Pin Source Current vs. Output Voltage
I/O PIN SOURCE CURRENT vs. OUTPUT VOLTAGE
Vcc = 5V
20
TA = 25˚C
18
16
TA = 85˚C
14
I
OH (mA)
12
10
8
6
4
2
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
VOH (V)
55
Figure 55. I/O Pin Sink Current vs. Output Voltage
I/O PIN SINK CURRENT vs. OUTPUT VOLTAGE
Vcc = 2.7V
25
TA = 25˚C
20
TA = 85˚C
10
I
OL (mA)
15
5
0
0
0.5
1
1.5
2
VOL (V)
Figure 56. I/O Pin Source Current vs. Output Voltage
I/O PIN SOURCE CURRENT vs. OUTPUT VOLTAGE
Vcc = 2.7V
6
TA = 25˚C
5
TA = 85˚C
3
I
OH (mA)
4
2
1
0
0
0.5
1
1.5
VOH (V)
Note:
56
Input threshold is measured at the center point of the hysteresis.
AT90S1200
2
2.5
3
AT90S1200
Figure 57. I/O Pin Input Threshold Voltage vs. VCC
I/O PIN INPUT THRESHOLD VOLTAGE vs. Vcc
TA = 25˚C
2.5
Threshold Voltage (V)
2
1.5
1
0.5
0
2.7
4.0
5.0
Vcc
Figure 58. I/O Pin Input Hysteresis vs. VCC
I/O PIN INPUT HYSTERESIS vs. Vcc
TA = 25˚C
0.18
0.16
Input hysteresis (V)
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
2.7
4.0
5.0
Vcc
57
AT90S1200 Register Summary
Address
$3F
$3E
$3D
$3C
$3B
$3A
$39
$38
$37
$36
$35
$34
$33
$32
$31
$30
$2F
$2E
$2D
$2C
$2B
$2A
$29
$28
$27
$26
$25
$24
$23
$22
$21
$20
$1F
$1E
$1D
$1C
$1B
$1A
$19
$18
$17
$16
$15
$14
$13
$12
$11
$10
$0F
...
$09
$08
…
$00
Notes:
58
Name
SREG
Reserved
Reserved
Reserved
GIMSK
Reserved
TIMSK
TIFR
Reserved
Reserved
MCUCR
Reserved
TCCR0
TCNT0
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
WDTCR
Reserved
Reserved
EEAR
EEDR
EECR
Reserved
Reserved
Reserved
PORTB
DDRB
PINB
Reserved
Reserved
Reserved
PORTD
DDRD
PIND
Reserved
Reserved
Reserved
ACSR
Reserved
Reserved
Bit 7
I
Bit 6
T
Bit 5
H
Bit 4
S
Bit 3
V
Bit 2
N
Bit 1
Z
Bit 0
C
Page
page 11
-
INT0
-
-
-
-
-
-
page 16
-
-
-
-
-
-
TOIE0
TOV0
-
page 16
page 16
-
-
SE
SM
-
-
ISC01
ISC00
page 17
-
-
-
CS02
CS01
CS00
page 20
page 20
-
-
-
WDP2
WDP1
WDP0
page 21
EEWE
EERE
page 22
page 23
page 23
-
Timer/Counter0 (8 Bits)
-
WDE
EEPROM Address Register
EEPROM Data Register
-
-
-
-
PORTB
DDB7
PINB7
PORTB
DDB6
PINB6
PORTB
DDB5
PINB5
PORTB
DDB4
PINB4
PORTB
DDB3
PINB3
PORTB
DDB2
PINB2
PORTB
DDB1
PINB1
PORTB
DDB0
PINB0
page 26
page 26
page 26
-
PORTD
DDD6
PIND6
PORTD
DDD5
PIND5
PORTD
DDD4
PIND4
PORTD
DDD3
PIND3
PORTD
DDD2
PIND2
PORTD
DDD1
PIND1
PORTD
DDD0
PIND0
page 30
page 30
page 30
ACD
-
ACO
ACI
ACIE
-
ACIS1
ACIS0
page 24
1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses
should never be written.
2. Some of the status flags are cleared by writing a logical “1” to them. Note that the CBI and SBI instructions will operate on all
bits in the I/O register, writing a “1” back into any flag read as set, thus clearing the flag. The CBI and SBI instructions work
with registers $00 to $1F only.
AT90S1200
AT90S1200
Instruction Set Summary
Mnemonic
Operands
Description
ARITHMETIC AND LOGIC INSTRUCTIONS
ADD
Rd, Rr
Add Two Registers
ADC
Rd, Rr
Add with Carry Two Registers
SUB
Rd, Rr
Subtract Two Registers
SUBI
Rd, K
Subtract Constant from Register
SBC
Rd, Rr
Subtract with Carry Two Registers
SBCI
Rd, K
Subtract with Carry Constant from Reg.
AND
Rd, Rr
Logical AND Registers
ANDI
Rd, K
Logical AND Register and Constant
OR
Rd, Rr
Logical OR Registers
ORI
Rd, K
Logical OR Register and Constant
EOR
Rd, Rr
Exclusive OR Registers
COM
Rd
One’s Complement
NEG
Rd
Two’s Complement
SBR
Rd, K
Set Bit(s) in Register
CBR
Rd, K
Clear Bit(s) in Register
INC
Rd
Increment
DEC
Rd
Decrement
TST
Rd
Test for Zero or Minus
CLR
Rd
Clear Register
SER
Rd
Set Register
BRANCH INSTRUCTIONS
RJMP
k
Relative Jump
RCALL
k
Relative Subroutine Call
RET
Subroutine Return
RETI
Interrupt Return
CPSE
Rd, Rr
Compare, Skip if Equal
CP
Rd, Rr
Compare
CPC
Rd, Rr
Compare with Carry
CPI
Rd, K
Compare Register with Immediate
SBRC
Rr, b
Skip if Bit in Register Cleared
SBRS
Rr, b
Skip if Bit in Register is Set
SBIC
P, b
Skip if Bit in I/O Register Cleared
SBIS
P, b
Skip if Bit in I/O Register is Set
BRBS
s, k
Branch if Status Flag Set
BRBC
s, k
Branch if Status Flag Cleared
BREQ
k
Branch if Equal
BRNE
k
Branch if Not Equal
BRCS
k
Branch if Carry Set
BRCC
k
Branch if Carry Cleared
BRSH
k
Branch if Same or Higher
BRLO
k
Branch if Lower
BRMI
k
Branch if Minus
BRPL
k
Branch if Plus
BRGE
k
Branch if Greater or Equal, Signed
BRLT
k
Branch if Less than Zero, Signed
BRHS
k
Branch if Half-carry Flag Set
BRHC
k
Branch if Half-carry Flag Cleared
BRTS
k
Branch if T-Flag Set
BRTC
k
Branch if T-Flag Cleared
BRVS
k
Branch if Overflow Flag is Set
BRVC
k
Branch if Overflow Flag is Cleared
BRIE
k
Branch if Interrupt Enabled
BRID
k
Branch if Interrupt Disabled
DATA TRANSFER INSTRUCTIONS
LD
Rd, Z
Load Register Indirect
ST
Z, Rr
Store Register Indirect
MOV
Rd, Rr
Move between Registers
LDI
Rd, K
Load Immediate
IN
Rd, P
In Port
OUT
P, Rr
Out Port
Operation
Flags
# Clocks
Rd ← Rd + Rr
Rd ← Rd + Rr + C
Rd ← Rd - Rr
Rd ← Rd - K
Rd ← Rd - Rr - C
Rd ← Rd - K - C
Rd ← Rd • Rr
Rd ← Rd • K
Rd ← Rd v Rr
Rd ← Rd v K
Rd ← Rd ⊕ Rr
Rd ← $FF - Rd
Rd ← $00 - Rd
Rd ← Rd v K
Rd ← Rd • (FFh - K)
Rd ← Rd + 1
Rd ← Rd - 1
Rd ← Rd • Rd
Rd ← Rd ⊕ Rd
Rd ← $FF
Z,C,N,V,H
Z,C,N,V,H
Z,C,N,V,H
Z,C,N,V,H
Z,C,N,V,H
Z,C,N,V,H
Z,N,V
Z,N,V
Z,N,V
Z,N,V
Z,N,V
Z,C,N,V
Z,C,N,V,H
Z,N,V
Z,N,V
Z,N,V
Z,N,V
Z,N,V
Z,N,V
None
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
PC ← PC + k + 1
PC ← PC + k + 1
PC ← STACK
PC ← STACK
if (Rd = Rr) PC ← PC + 2 or 3
Rd - Rr
Rd - Rr - C
Rd - K
if (Rr(b) = 0) PC ← PC + 2 or 3
if (Rr(b) = 1) PC ← PC + 2 or 3
if (P(b)= 0) PC ← PC + 2 or 3
if (P(b) = 1) PC ← PC + 2 or 3
if (SREG(s) = 1) then PC ← PC + k + 1
if (SREG(s) = 0) then PC ← PC + k + 1
if (Z = 1) then PC ← PC + k + 1
if (Z = 0) then PC ← PC + k + 1
if (C = 1) then PC ← PC + k + 1
if (C = 0) then PC ← PC + k + 1
if (C = 0) then PC ← PC + k + 1
if (C = 1) then PC ← PC + k + 1
if (N = 1) then PC ← PC + k + 1
if (N = 0) then PC ← PC + k + 1
if (N ⊕ V = 0) then PC ← PC + k + 1
if (N ⊕ V = 1) then PC ← PC + k + 1
if (H = 1) then PC ← PC + k + 1
if (H = 0) then PC ← PC + k + 1
if (T = 1) then PC ← PC + k + 1
if (T = 0) then PC ← PC + k + 1
if (V = 1) then PC ← PC + k + 1
if (V = 0) then PC ← PC + k + 1
if (I = 1) then PC ← PC + k + 1
if (I = 0) then PC ← PC + k + 1
None
None
None
I
None
Z,N,V,C,H
Z,N,V,C,H
Z,N,V,C,H
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
2
3
4
4
1/2
1
1
1
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
Rd ← (Z)
(Z) ← Rr
Rd ← Rr
Rd ← K
Rd ← P
P ← Rr
None
None
None
None
None
None
2
2
1
1
1
1
59
Instruction Set Summary (Continued)
Mnemonic
Operands
Description
BIT AND BIT-TEST INSTRUCTIONS
SBI
P, b
Set Bit in I/O Register
CBI
P, b
Clear Bit in I/O Register
LSL
Rd
Logical Shift Left
LSR
Rd
Logical Shift Right
ROL
Rd
Rotate Left through Carry
ROR
Rd
Rotate Right through Carry
ASR
Rd
Arithmetic Shift Right
SWAP
Rd
Swap Nibbles
BSET
s
Flag Set
BCLR
s
Flag Clear
BST
Rr, b
Bit Store from Register to T
BLD
Rd, b
Bit Load from T to Register
SEC
Set Carry
CLC
Clear Carry
SEN
Set Negative Flag
CLN
Clear Negative Flag
SEZ
Set Zero Flag
CLZ
Clear Zero Flag
SEI
Global Interrupt Enable
CLI
Global Interrupt Disable
SES
Set Signed Test Flag
CLS
Clear Signed Test Flag
SEV
Set Two’s Complement Overflow
CLV
Clear Two’s Complement Overflow
SET
Set T in SREG
CLT
Clear T in SREG
SEH
Set Half-carry Flag in SREG
CLH
Clear Half-carry Flag in SREG
NOP
No Operation
SLEEP
Sleep
WDR
Watchdog Reset
60
AT90S1200
Operation
Flags
I/O(P,b) ← 1
I/O(P,b) ← 0
Rd(n+1) ← Rd(n), Rd(0) ← 0
Rd(n) ← Rd(n+1), Rd(7) ← 0
Rd(0) ← C,Rd(n+1) ← Rd(n),C ← Rd(7)
Rd(7) ← C,Rd(n) ← Rd(n+1),C ← Rd(0)
Rd(n) ← Rd(n+1), n = 0..6
Rd(3..0) ← Rd(7..4),Rd(7..4) ← Rd(3..0)
SREG(s) ← 1
SREG(s) ← 0
T ← Rr(b)
Rd(b) ← T
C←1
C←0
N ←1
N←0
Z←1
Z←0
I←1
I←0
S←1
S←0
V←1
V←0
T← 1
T ←0
H←1
H←0
None
None
Z,C,N,V
Z,C,N,V
Z,C,N,V
Z,C,N,V
Z,C,N,V
None
SREG(s)
SREG(s)
T
None
C
C
N
N
Z
Z
I
I
S
S
V
V
T
T
H
H
None
None
None
(see specific descr. for Sleep function)
(see specific descr. for WDR/timer)
# Clocks
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
AT90S1200
Ordering Information(1)
Speed (MHz)
Power Supply
Ordering Code
Package
4
2.7 - 6.0V
AT90S1200-4PC
AT90S1200-4SC
AT90S1200-4YC
20P3
20S
20Y
Commercial
(0°C to 70°C)
AT90S1200-4PI
AT90S1200-4SI
AT90S1200-4YI
20P3
20S
20Y
Industrial
(-40°C to 85°C)
AT90S1200-12PC
AT90S1200-12SC
AT90S1200-12YC
20P3
20S
20Y
Commercial
(0°C to 70°C)
AT90S1200-12PI
AT90S1200-12SI
AT90S1200-12YI
20P3
20S
20Y
Industrial
(-40°C to 85°C)
12
Note:
4.0 - 6.0V
Operation Range
1. Order AT90S1200A-XXX for devices with the RCEN fuse programmed.
Package Type
20P3
20-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
20S
20-lead, 0.300" Wide, Plastic Gull Wing Small Outline (SOIC)
20Y
20-lead, 5.3 mm Wide, Plastic Shrink Small Outline Package (SSOP)
61
Packaging Information
20P3, 20-lead, 0.300" Wide,
Plastic Dual Inline Package (PDIP)
Dimensions in Inches and (Millimeters)
20S, 20-lead, 0.300" Wide,
Plastic Gull Wing Small Outline (SOIC)
Dimensions in Inches and (Millimeters)
JEDEC STANDARD MS-001 BA
1.060(26.9)
.980(24.9)
0.020 (0.508)
0.013 (0.330)
PIN
1
.280(7.11)
.240(6.10)
0.299 (7.60) 0.420 (10.7)
0.291 (7.39) 0.393 (9.98)
PIN 1
.090(2.29)
MAX
.900(22.86) REF
.210(5.33)
MAX
.005(.127)
MIN
.050 (1.27) BSC
SEATING
PLANE
0.513 (13.0)
0.497 (12.6)
.015(.381) MIN
.150(3.81)
.115(2.92)
.070(1.78)
.045(1.13)
.110(2.79)
.090(2.29)
0.012 (0.305)
0.003 (0.076)
.325(8.26)
.300(7.62)
0 REF
15
.014(.356)
.008(.203)
0
REF
8
0.013 (0.330)
0.009 (0.229)
.430(10.92) MAX
0.035 (0.889)
0.015 (0.381)
20Y, 20-lead, 5.3 mm Wide,
Plastic Shrink Small Outline Package (SSOP)
Dimensions in Millimeters and (Inches)
0.38 (.015)
0.25 (.010)
5.38 (.212) 7.90 (.311)
5.20 (.205) 7.65 (.301)
PIN 1 ID
0.65 (.0256) BSC
7.33 (.289)
7.07 (.278)
2.67 (.105)
2.34 (.092)
0.21 (.008)
0.05 (.002)
0.20 (.008)
0.09 (.004)
0 REF
8
62
0.105 (2.67)
0.092 (2.34)
.022(.559)
.014(.356)
0.95 (.037)
0.63 (.025)
AT90S1200
Atmel Headquarters
Atmel Operations
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Atmel Smart Card ICs
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TEL (81) 3-3523-3551
FAX (81) 3-3523-7581
Fax-on-Demand
North America:
1-(800) 292-8635
International:
1-(408) 441-0732
e-mail
[email protected]
Web Site
http://www.atmel.com
BBS
1-(408) 436-4309
© Atmel Corporation 2000.
Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for
any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without
notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel’s products are
not authorized for use as critical components in life suppor t devices or systems.
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and/or
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are registered trademarks and trademarks of Atmel Corporation.
Terms and product names in this document may be trademarks of others.
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