ATMEL ATTINY12L-4SC

Features
• Utilizes the AVR® RISC Architecture
• High-performance and Low-power 8-bit RISC Architecture
•
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•
•
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•
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– 90 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Up to 8 MIPS Throughput at 8 MHz
Nonvolatile Program and Data Memory
– 1K Byte of Flash Program Memory
In-System Programmable (ATtiny12)
Endurance: 1,000 Write/Erase Cycles (ATtiny11/12)
– 64 Bytes of In-System Programmable EEPROM Data Memory for ATtiny12
Endurance: 100,000 Write/Erase Cycles
– Programming Lock for Flash Program and EEPROM Data Security
Peripheral Features
– Interrupt and Wake-up on Pin Change
– One 8-bit Timer/Counter with Separate Prescaler
– On-chip Analog Comparator
– Programmable Watchdog Timer with On-chip Oscillator
Special Microcontroller Features
– Low-power Idle and Power-down Modes
– External and Internal Interrupt Sources
– In-System Programmable via SPI Port (ATtiny12)
– Enhanced Power-on Reset Circuit (ATtiny12)
– Internal Calibrated RC Oscillator (ATtiny12)
Specification
– Low-power, High-speed CMOS Process Technology
– Fully Static Operation
Power Consumption at 4 MHz, 3V, 25°C
– Active: 2.2 mA
– Idle Mode: 0.5 mA
– Power-down Mode: <1 µA
Packages
– 8-pin PDIP and SOIC
Operating Voltages
– 1.8 - 5.5V for ATtiny12V-1
– 2.7 - 5.5V for ATtiny11L-2 and ATtiny12L-4
– 4.0 - 5.5V for ATtiny11-6 and ATtiny12-8
Speed Grades
– 0 - 1.2 MHz (ATtiny12V-1)
– 0 - 2 MHz (ATtiny11L-2)
– 0 - 4 MHz (ATtiny12L-4)
– 0 - 6 MHz (ATtiny11-6)
– 0 - 8 MHz (ATtiny12-8)
8-bit
Microcontroller
with 1K Byte
Flash
ATtiny11
ATtiny12
Pin Configuration
ATtiny11
PDIP/SOIC
(RESET) PB5
(XTAL1) PB3
(XTAL2) PB4
GND
1
2
3
4
8
7
6
5
ATtiny12
PDIP/SOIC
VCC
PB2 (T0)
PB1 (INT0/AIN1)
PB0 (AIN0)
(RESET) PB5
(XTAL1) PB3
(XTAL2) PB4
GND
1
2
3
4
8
7
6
5
VCC
PB2 (SCK/T0)
PB1 (MISO/INT0/AIN1)
PB0 (MOSI/AIN0)
Rev. 1006D–AVR–07/03
1
Description
The ATtiny11/12 is a low-power CMOS 8-bit microcontroller based on the AVR RISC
architecture. By executing powerful instructions in a single clock cycle, the ATtiny11/12
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 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.
Table 1. Parts Description
ATtiny11 Block Diagram
Device
Flash
EEPROM
Register
Voltage Range
Frequency
ATtiny11L
1K
-
32
2.7 - 5.5V
0-2 MHz
ATtiny11
1K
-
32
4.0 - 5.5V
0-6 MHz
ATtiny12V
1K
64 B
32
1.8 - 5.5V
0-1.2 MHz
ATtiny12L
1K
64 B
32
2.7 - 5.5V
0-4 MHz
ATtiny12
1K
64 B
32
4.0 - 5.5V
0-8 MHz
The ATtiny11 provides the following features: 1K bytes of Flash, up to five general-purpose I/O lines, one input line, 32 general-purpose working registers, an 8-bit
timer/counter, internal and external interrupts, programmable Watchdog Timer with
internal oscillator, and two software-selectable power-saving modes. The Idle Mode
stops the CPU while allowing the timer/counters 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 interrupt or hardware reset. The wake-up
or interrupt on pin change features enable the ATtiny11 to be highly responsive to external events, still featuring the lowest power consumption while in the power-down modes.
The device is manufactured using Atmel’s high-density nonvolatile memory technology.
By combining an RISC 8-bit CPU with Flash on a monolithic chip, the Atmel ATtiny11 is
a powerful microcontroller that provides a highly-flexible and cost-effective solution to
many embedded control applications.
The ATtiny11 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.
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1006D–AVR–07/03
ATtiny11/12
Figure 1. The ATtiny11 Block Diagram
VCC
8-BIT DATA BUS
INTERNAL
OSCILLATOR
GND
PROGRAM
COUNTER
STACK
POINTER
WATCHDOG
TIMER
PROGRAM
FLASH
HARDWARE
STACK
MCU CONTROL
REGISTER
INSTRUCTION
REGISTER
GENERALPURPOSE
REGISTERS
INSTRUCTION
DECODER
CONTROL
LINES
TIMING AND
CONTROL
MCU STATUS
REGISTER
Z
TIMER/
COUNTER
ALU
INTERRUPT
UNIT
STATUS
REGISTER
ANALOG
COMPARATOR
+
-
PROGRAMMING
LOGIC
OSCILLATORS
DATA REGISTER
PORTB
DATA DIR.
REG. PORTB
PORTB DRIVERS
PB0-PB5
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1006D–AVR–07/03
ATtiny12 Block Diagram
Figure 2. The ATtiny12 Block Diagram
VCC
8-BIT DATA BUS
INTERNAL
OSCILLATOR
INTERNAL
CALIBRATED
OSCILLATOR
TIMING AND
CONTROL
GND
PROGRAM
COUNTER
STACK
POINTER
WATCHDOG
TIMER
PROGRAM
FLASH
HARDWARE
STACK
MCU CONTROL
REGISTER
INSTRUCTION
REGISTER
GENERALPURPOSE
REGISTERS
INSTRUCTION
DECODER
CONTROL
LINES
ANALOG
COMPARATOR
+
-
PROGRAMMING
LOGIC
MCU STATUS
REGISTER
Z
TIMER/
COUNTER
ALU
INTERRUPT
UNIT
STATUS
REGISTER
EEPROM
OSCILLATORS
SPI
DATA REGISTER
PORTB
DATA DIR.
REG. PORTB
PORTB DRIVERS
PB0-PB5
The ATtiny12 provides the following features: 1K bytes of Flash, 64 bytes EEPROM, up
to six general-purpose I/O lines, 32 general-purpose working registers, an 8-bit
timer/counter, internal and external interrupts, programmable Watchdog Timer with
internal oscillator, and two software-selectable power-saving modes. The Idle Mode
stops the CPU while allowing the timer/counters 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 interrupt or hardware reset. The wake-up
or interrupt on pin change features enable the ATtiny12 to be highly responsive to external events, still featuring the lowest power consumption while in the power-down modes.
The device is manufactured using Atmel’s high-density nonvolatile memory technology.
By combining an RISC 8-bit CPU with Flash on a monolithic chip, the Atmel ATtiny12 is
a powerful microcontroller that provides a highly-flexible and cost-effective solution to
many embedded control applications.
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1006D–AVR–07/03
ATtiny11/12
The ATtiny12 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 (PB5..PB0)
Port B is a 6-bit I/O port. PB4..0 are I/O pins that can provide internal pull-ups (selected
for each bit). On ATtiny11, PB5 is input only. On ATtiny12, PB5 is input or open-drain
output. The port pins are tri-stated when a reset condition becomes active, even if the
clock is not running. The use of pins PB5..3 as input or I/O pins is limited, depending on
reset and clock settings, as shown below.
Table 2. PB5..PB3 Functionality vs. Device Clocking Options
Device Clocking Option
PB5
PB4
PB3
(2)
-
Input(3)/I/O(4)
-
-
External Crystal
-
Used
Used
External Low-frequency Crystal
-
Used
Used
External Ceramic Resonator
-
Used
Used
External RC Oscillator
-
I/O(5)
Used
External Clock
-
I/O
Used
Internal RC Oscillator
-
I/O
I/O
External Reset Enabled
Used
External Reset Disabled
Notes:
1.
2.
3.
4.
5.
(1)
-
“Used” means the pin is used for reset or clock purposes.
“-” means the pin function is unaffected by the option.
Input means the pin is a port input pin.
On ATtiny11, PB5 is input only. On ATtiny12, PB5 is input or open-drain output.
I/O means the pin is a port input/output pin.
XTAL1
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2
Output from the inverting oscillator amplifier.
RESET
Reset input. 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.
Clock Options
The device has the following clock source options, selectable by Flash fuse bits as
shown:
Table 3. Device Clocking Options Select
Device Clocking Option
ATtiny11 CKSEL2..0
ATtiny12 CKSEL3..0
External Crystal/Ceramic Resonator
111
1111 - 1010
External Low-frequency Crystal
110
1001 - 1000
External RC Oscillator
101
0111 - 0101
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1006D–AVR–07/03
Table 3. Device Clocking Options Select (Continued)
Device Clocking Option
ATtiny11 CKSEL2..0
ATtiny12 CKSEL3..0
Internal RC Oscillator
100
0100 - 0010
External Clock
000
0001 - 0000
Reserved
Other Options
Note:
“1” means unprogrammed, “0” means programmed.
-
The various choices for each clocking option give different start-up times as shown in
Table 7 on page 18 and Table 9 on page 20.
Internal RC Oscillator
The internal RC oscillator option is an on-chip oscillator running at a fixed frequency of 1
MHz in ATtiny11 and 1.2 MHz in ATtiny12. If selected, the device can operate with no
external components. The device is shipped with this option selected. On ATtiny11, the
Watchdog Oscillator is used as a clock, while ATtiny12 uses a separate calibrated
oscillator.
Crystal Oscillator
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can
be configured for use as an on-chip oscillator, as shown in Figure 3. Either a quartz
crystal or a ceramic resonator may be used. Maximum frequency for crystal and resonators is 4 MHz. Minimum voltage for running on a low-frequency crystal is 2.5V.
Figure 3. Oscillator Connections
MAX 1 HC BUFFER
HC
C2
C1
XTAL2
XTAL1
GND
Note:
External Clock
When using the MCU Oscillator as a clock for an external device, an HC buffer should be
connected as indicated in the figure.
To drive the device from an external clock source, XTAL1 should be driven as shown in
Figure 4.
Figure 4. External Clock Drive Configuration
PB4 (XTAL2)
EXTERNAL
OSCILLATOR
SIGNAL
XTAL1
GND
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ATtiny11/12
External RC Oscillator
For timing insensitive applications, the external RC configuration shown in Figure 5 can
be used. For details on how to choose R and C, see Table 29 on page 59. The external
RC oscillator is sensitive to noise from neighboring pins, and to avoid problems, PB5
(RESET) should be used as an output or reset pin, and PB4 should be used as an output pin.
Figure 5. External RC Configuration
VCC
R
PB4 (XTAL2)
XTAL1
C
GND
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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.
Two of the 32 registers can be used as a 16-bit pointer for indirect memory access. This
pointer is called the Z-pointer, and can address the register file and the Flash program
memory.
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 2
shows the ATtiny11/12 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 two-stage pipelining. 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 reprogrammable 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 as control
registers, timer/counters, and other I/O functions. The memory spaces in the AVR architecture are all linear and regular memory maps.
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ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 6. The ATtiny11/12 AVR RISC Architecture
8-bit Data Bus
512 x 16
Program
Flash
Program
Counter
Status
and Test
Control
Registers
Interrupt
Unit
32 x 8
Generalpurpose
Registers
Instruction
Register
SPI Unit
(ATtiny12 only)
8-bit
Timer/Counter
Direct Addressing
Instruction
Decoder
Watchdog
Timer
ALU
Analog
Comparator
Control Lines
64 x 8 EEPROM
(ATtiny12 only)
6
I/O Lines
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 separ a t e i n t er r u p t v e c t o r i n t he i n t er r u p t v e c t o r t ab l e a t t he b e g i n ni n g o f t he
program memory. The different interrupts have priority in accordance with their interrupt
vector position. The lower the interrupt vector address, the higher the priority.
General-purpose
Register File
Figure 7 shows the structure of the 32 general-purpose registers in the CPU.
Figure 7. AVR CPU General-purpose Working Registers
7
0
R0
R1
R2
General-
…
purpose
…
Working
R28
Registers
R29
R30 (Z-register low byte)
R31 (Z-register high byte)
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, and 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,
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1006D–AVR–07/03
OR and all other operations between two registers or on a single register apply to the
entire register file.
Registers 30 and 31 form a 16-bit pointer (the Z-pointer) which is used for indirect Flash
memory and register file access. When the register file is accessed, the contents of R31
are discarded by the CPU.
ALU – Arithmetic Logic
Unit
The high-performance AVR ALU operates in direct connection with all the 32 generalpurpose 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. Some microcontrollers in the AVR product family feature a hardware multiplier in the arithmetic part of the ALU.
Flash Program Memory
The ATtiny11/12 contains 1K bytes on-chip Flash memory for program storage. Since
all instructions are single 16-bit words, the Flash is organized as 512 x 16 words. The
Flash memory has an endurance of at least 1000 write/erase cycles.
The ATtiny11/12 Program Counter is 9 bits wide, thus addressing the 512 words Flash
program memory.
See page 46 for a detailed description on Flash memory programming.
Program and Data
Addressing Modes
The ATtiny11/12 AVR RISC Microcontroller supports powerful and efficient addressing
modes. This section describes the different addressing modes supported in the
ATtiny11/12. 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.
Register Direct, Single
Register Rd
Figure 8. Direct Single-register Addressing
The operand is contained in register d (Rd).
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ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Register Indirect
Figure 9. Indirect Register Addressing
REGISTER FILE
0
Z-register
30
31
The register accessed is the one pointed to by the Z-register (R31, R30).
Register Direct, Two Registers
Rd and Rr
Figure 10. 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 11. 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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1006D–AVR–07/03
Relative Program Addressing,
RJMP and RCALL
Figure 12. Relative Program Memory Addressing
+1
Program execution continues at address PC + k + 1. The relative address k is -2048 to
2047.
Constant Addressing Using
the LPM Instruction
Figure 13. Code Memory Constant Addressing
PROGRAM MEMORY
$000
15
1 0
Z-REGISTER
$1FF
Constant byte address is specified by the Z-register contents. The 15 MSBs select word
address (0 - 511), the LSB selects low byte if cleared (LSB = 0) or high byte if set
(LSB = 1).
Subroutine and Interrupt
Hardware Stack
The ATtiny11/12 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. Pushing four return addresses A1, A2, A3, and
A4, followed by four subroutine or interrupt returns, will pop A4, A3, A2, and once more
A2 from the hardware stack.
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ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
EEPROM Data Memory
The ATtiny12 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 38, specifying the EEPROM Address Register, the EEPROM
Data Register, and the EEPROM Control Register.
For SPI data downloading, see “Memory Programming” on page 46 for a detailed
description.
Memory Access and
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 14 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.
Figure 14. 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 15 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 15. Single-cycle ALU Operation
T1
T2
T3
T4
System Clock Ø
Total Execution Time
Register Operands Fetch
ALU Operation Execute
Result Write Back
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1006D–AVR–07/03
I/O Memory
The I/O space definition of the ATtiny11/12 is shown in the following table:
Table 4. ATtiny11/12 I/O Space
Address Hex
Name
Device
Function
$3F
SREG
ATtiny11/12
Status Register
$3B
GIMSK
ATtiny11/12
General Interrupt Mask Register
$3A
GIFR
ATtiny11/12
General Interrupt Flag Register
$39
TIMSK
ATtiny11/12
Timer/Counter Interrupt Mask Register
$38
TIFR
ATtiny11/12
Timer/Counter Interrupt Flag Register
$35
MCUCR
ATtiny11/12
MCU Control Register
$34
MCUSR
ATtiny11/12
MCU Status Register
$33
TCCR0
ATtiny11/12
Timer/Counter0 Control Register
$32
TCNT0
ATtiny11/12
Timer/Counter0 (8-bit)
$31
OSCCAL
ATtiny12
Oscillator Calibration Register
$21
WDTCR
ATtiny11/12
Watchdog Timer Control Register
$1E
EEAR
ATtiny12
EEPROM Address Register
$1D
EEDR
ATtiny12
EEPROM Data Register
$1C
EECR
ATtiny12
EEPROM Control Register
$18
PORTB
ATtiny11/12
Data Register, Port B
$17
DDRB
ATtiny11/12
Data Direction Register, Port B
$16
PINB
ATtiny11/12
Input Pins, Port B
$08
ACSR
ATtiny11/12
Analog Comparator Control and Status Register
Note:
Reserved and unused locations are not shown in the table.
All the different ATtiny11/12 I/O 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 Summary for more details.
For compatibility with future devices, reserved bits should be written to zero if accessed.
Reserved I/O memory addressed should never be written.
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
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1006D–AVR–07/03
ATtiny11/12
global interrupt enable register 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 arithmetic. See the
Instruction Set description for detailed information.
• Bit 2 - N: Negative Flag
The negative flag N indicates a negative result from an arithmetical or logical operation.
See the Instruction Set description for detailed information.
• Bit 1 - Z: Zero Flag
The zero flag Z indicates a zero result from an arithmetical or logical operation. See the
Instruction Set description for detailed information.
• Bit 0 - C: Carry Flag
The carry flag C indicates a carry in an arithmetical or logical 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 ATtiny11 provides four different interrupt sources and the ATtiny12 provides five.
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 which
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 5. The list
also determines the priority levels of the different interrupts. The lower the address, the
higher the priority level. RESET has the highest priority, and next is INT0 – the External
Interrupt Request 0, etc.
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1006D–AVR–07/03
Table 5. Reset and Interrupt Vectors
Vector No.
Device
Program Address
Source
Interrupt Definition
1
ATtiny11
$000
RESET
External Pin, Power-on
Reset and Watchdog
Reset
1
ATtiny12
$000
RESET
External Pin, Power-on
Reset, Brown-out Reset
and Watchdog Reset
2
ATtiny11/12
$001
INT0
3
ATtiny11/12
$002
I/O Pins
4
ATtiny11/12
$003
TIMER0, OVF0
5
ATtiny11
$004
ANA_COMP
5
ATtiny12
$004
EE_RDY
6
ATtiny12
$005
ANA_COMP
External Interrupt
Request 0
Pin Change Interrupt
Timer/Counter0
Overflow
Analog Comparator
EEPROM Ready
Analog Comparator
The most typical and general program setup for the reset and interrupt vector addresses
for the ATtiny11 are:
Address
Labels
Code
Comments
$000
rjmp
RESET
; Reset handler
$001
rjmp
EXT_INT0
; IRQ0 handler
$002
rjmp
PIN_CHANGE
; Pin change handler
$003
rjmp
TIM0_OVF
; Timer0 overflow handler
$004
rjmp
ANA_COMP
; Analog Comparator handler
MAIN:
<instr>
xxx
; Main program start
…
…
;
$005
…
…
The most typical and general program setup for the reset and interrupt vector addresses
for the ATtiny12 are:
Address
Labels
Code
Comments
$000
rjmp
RESET
; Reset handler
$001
rjmp
EXT_INT0
; IRQ0 handler
$002
rjmp
PIN_CHANGE
; Pin change handler
$003
rjmp
TIM0_OVF
; Timer0 overflow handler
$004
rjmp
EE_RDY
; EEPROM Ready handler
$005
rjmp
ANA_COMP
; Analog Comparator handler
MAIN:
<instr>
xxx
; Main program start
…
…
;
$006
…
16
…
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Reset Sources
The ATtiny11/12 provides three or four 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.
•
Brown-out Reset. The MCU is reset when the supply voltage VCC falls below a
certain voltage (ATtiny12 only).
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 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 16 shows the reset logic for the
ATtiny11. Figure 17 shows the reset logic for the ATtiny12. Table 6 defines the electrical
parameters of the reset circuitry for ATtiny11. Table 8 shows the parameters of the reset
circuitry for ATtiny12.
Figure 16. Reset Logic for the ATtiny11
RESET
Reset Circuit
POR
Watchdog
Timer
On-chip
RC Oscillator
S
Q
20-stage Ripple Counter
Q3
Q9
Q13
R
Q
INTERNAL
RESET
Power-on Reset
Circuit
COUNTER RESET
VCC
Q19
FSTRT
CKSEL
Table 6. Reset Characteristics for the ATtiny11
Symbol
VPOT(1)
VRST
Note:
Parameter
Min
Typ
Max
Units
Power-on Reset Threshold Voltage (rising)
1.0
1.4
1.8
V
Power-on Reset Threshold Voltage (falling)
0.4
0.6
0.8
V
RESET Pin Threshold Voltage
0.6 VCC
V
1. The Power-on Reset will not work unless the supply voltage has been below VPOT
(falling).
17
1006D–AVR–07/03
Power-on Reset for the
ATtiny11
A Power-on Reset (POR) circuit ensures that the device is reset from power-on. As
shown in Figure 16, an internal timer is clocked from the watchdog timer. This timer prevents the MCU from starting a certain period after V CC has reached the Power-on
Threshold Voltage – VPOT. See Figure 18. The total reset period is the Delay Time-out
period – tTOUT. The FSTRT fuse bit in the Flash can be programmed to give a shorter
start-up time.The start-up times for the different clock options are shown in the following
table. The Watchdog Oscillator is used for timing the start-up time, and this oscillator is
voltage dependent as shown in the section “ATtiny11 Typical Characteristics” on page
60.
Table 7. Start-up Times for the ATtiny11 (VCC = 2.7V)
Start-up Time tTOUT
Selected Clock Option
FSTRT Unprogrammed
FSTRT Programmed
External Crystal
67 ms
4.2 ms
External Ceramic Resonator
67 ms
4.2 ms
External Low-frequency Crystal
4.2 s
4.2 s
External RC Oscillator
4.2 ms
67 µs
Internal RC Oscillator
4.2 ms
67 µs
External Clock
4.2 ms
5 clocks from reset,
2 clocks from power-down
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 19 for a timing example on this.
18
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 17. Reset Logic for the ATtiny12
DATA BUS
Power-on Reset
Circuit
BODEN
BODLEVEL
PORF
BORF
EXTRF
WDRF
MCU Status
Register (MCUSR)
Brown-out
Reset Circuit
CKSEL[3:0]
On-chip
RC Oscillator
Delay Counters
Full
CK
Table 8. Reset Characteristics for the ATtiny12
Symbol
Parameter
Condition
Min
Typ
Max
Units
Power-on Reset Threshold
Voltage (rising)
BOD disabled
1.0
1.4
1.8
V
BOD enabled
0.6
1.2
1.8
V
Power-on Reset Threshold
Voltage (falling)
BOD disabled
0.4
0.6
0.8
V
BOD enabled
0.6
1.2
1.8
V
VPOT(1)
VRST
RESET Pin Threshold
Voltage
VBOT
Brown-out Reset Threshold
Voltage
Note:
0.6VCC
V
(BODLEVEL = 1)
1.5
1.8
1.9
(BODLEVEL = 0)
2.3
2.7
2.8
V
1. The Power-on Reset will not work unless the supply voltage has been below VPOT
(falling).
19
1006D–AVR–07/03
Table 9. ATtiny12 Clock Options and Start-up Times
Clock Source
Start-up Time,
VCC = 1.8V,
BODLEVEL
Unprogrammed
Start-up Time,
VCC = 2.7V,
BODLEVEL
Programmed
1111
Ext. Crystal/Ceramic Resonator(1)
1K CK
1K CK
1110
Ext. Crystal/Ceramic Resonator(1)
3.6 ms + 1K CK
4.2 ms + 1K CK
1101
(1)
Ext. Crystal/Ceramic Resonator
57 ms 1K CK
67 ms + 1K CK
1100
Ext. Crystal/Ceramic Resonator
16K CK
16K CK
1011
Ext. Crystal/Ceramic Resonator
3.6 ms + 16K CK
4.2 ms + 16K CK
1010
Ext. Crystal/Ceramic Resonator
57 ms + 16K CK
67 ms + 16K CK
1001
Ext. Low-frequency Crystal
57 ms + 1K CK
67 ms + 1K CK
1000
Ext. Low-frequency Crystal
57 ms + 32K CK
67 ms + 32K CK
0111
Ext. RC Oscillator
6 CK
6 CK
0110
Ext. RC Oscillator
3.6 ms + 6 CK
4.2 ms + 6 CK
0101
Ext. RC Oscillator
57 ms + 6 CK
67 ms + 6 CK
0100
Int. RC Oscillator
6 CK
6 CK
0011
Int. RC Oscillator
3.6 ms + 6 CK
4.2 ms + 6 CK
0010
Int. RC Oscillator
57 ms + 6 CK
67 ms + 6 CK
0001
Ext. Clock
6 CK
6 CK
0000
Ext. Clock
3.6 ms + 6 CK
4.2 ms + 6 CK
CKSEL3..0
Note:
1. Due to the limited number of clock cycles in the start-up period, it is recommended
that Ceramic Resonator be used.
This table shows the start-up times from reset. From sleep, only the clock counting part
of the start-up time is used. The Watchdog oscillator is used for timing the real-time part
of the start-up time. The number of WDT oscillator cycles used for each time-out is
shown in Table 10.
Table 10. Number of Watchdog Oscillator Cycles
BODLEVEL
Time-out
Number of Cycles
Unprogrammed
3.6 ms (at Vcc = 1.8V)
256
Unprogrammed
57 ms (at Vcc = 1.8V)
4K
Programmed
4.2 ms (at Vcc = 2.7V)
1K
Programmed
67 ms (at Vcc = 2.7V)
16K
The frequency of the watchdog oscillator is voltage dependent as shown in the section
“ATtiny11 Typical Characteristics” on page 60.
Note that the BODLEVEL fuse can be used to select start-up times even if the Brownout Detection is disabled (by leaving the BODEN fuse unprogrammed).
The device is shipped with CKSEL3..0 = 0010.
20
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Power-on Reset for the
ATtiny12
A Power-on Reset (POR) pulse is generated by an on-chip detection circuit. The detection level is nominally 1.4V. The POR is activated whenever VCC is below the detection
level. The POR circuit can be used to trigger the start-up reset, as well as detect a failure in supply voltage.
The Power-on Reset (POR) circuit ensures that the device is reset from power-on.
Reaching the Power-on Reset threshold voltage invokes a delay counter, which determines the delay for which the device is kept in Reset after VCC rise. The time-out period
of the delay counter can be defined by the user through the CKSEL fuses. The different
selections for the delay period are presented in Table 9. The Reset signal is activated
again, without any delay, when the VCC decreases below detection level.
If the built-in start-up delay is sufficient, RESET can be connected to VCC directly or via
an external pull-up resistor. See Figure 18. 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 19 for a timing example on this.
Figure 18. MCU Start-up, RESET Tied to VCC.
VCC
RESET
VPOT
VRST
tTOUT
TIME-OUT
INTERNAL
RESET
Figure 19. MCU Start-up, RESET Extended Externally
VCC
RESET
VPOT
VRST
tTOUT
TIME-OUT
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.
21
1006D–AVR–07/03
Figure 20. External Reset during Operation
VCC
RESET
VRST
t TOUT
TIME-OUT
INTERNAL
RESET
Brown-out Detection
(ATtiny12)
ATtiny12 has an on-chip brown-out detection (BOD) circuit for monitoring the VCC level
during the operation. The BOD circuit can be enabled/disabled by the fuse BODEN.
When BODEN is enabled (BODEN programmed), and VCC decreases below the trigger
level, the brown-out reset is immediately activated. When VCC increases above the trigger level, the brown-out reset is deactivated after a delay. The delay is defined by the
user in the same way as the delay of POR signal, in Table 5. The trigger level for the
BOD can be selected by the fuse BODLEVEL to be 1.8V (BODLEVEL unprogrammed),
or 2.7V (BODLEVEL programmed). The trigger level has a hysteresis of 50 mV to
ensure spike-free brown-out detection.
The BOD circuit will only detect a drop in VCC if the voltage stays below the trigger level
for longer than 7 µs for trigger level 2.7V, 24 µs for trigger level 1.8V (typical values).
Figure 21. Brown-out Reset during Operation (ATtiny12)
VCC
VBOT-
VBOT+
RESET
TIME-OUT
tTOUT
INTERNAL
RESET
Note:
22
The hysteresis on VBOT: VBOT + = VBOT + 25 mV, VBOT- = VBOT - 25 mV.
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Watchdog Reset
When the Watchdog times out, it will generate a short reset pulse of 1 CK cycle duration. On the falling edge of this pulse, the delay timer starts counting the Time-out period
(tTOUT). Refer to page 36 for details on operation of the Watchdog.
Figure 22. Watchdog Reset during Operation
VCC
CK
MCU Status Register –
MCUSR of the ATtiny11
The MCU Status Register provides information on which reset source caused an MCU
reset.
Bit
7
6
5
4
3
2
1
0
$34
-
-
-
-
-
-
EXTRF
PORF
Read/Write
R
R
R
R
R
R
R/W
R/W
Initial Value
0
0
0
0
0
0
MCUSR
See bit description
• Bit 7..2 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11 and always read as zero.
• Bit 1 - EXTRF: EXTernal Reset Flag
After a power-on reset, this bit is undefined (X). It will be set by an external reset. A
watchdog reset will leave this bit unchanged.
• Bit 0 - PORF: Power-on Reset Flag
This bit is set by a power-on reset. A watchdog reset or an external reset will leave this
bit unchanged.
To summarize, the following table shows the value of these two bits after the three
modes of reset.
Table 11. PORF and EXTRF Values after Reset
Reset Source
Power-on
External Reset
Watchdog Reset
EXTRF
PORF
Undefined
1
1
Unchanged
Unchanged
Unchanged
To identify a reset condition, the user software should clear both the PORF and EXTRF
bits as early as possible in the program. Checking the PORF and EXTRF values is done
23
1006D–AVR–07/03
before the bits are cleared. If the bit is cleared before an external or watchdog reset
occurs, the source of reset can be found by using the following truth table:
Table 12. Reset Source Identification
MCU Status Register –
MCUSR for the ATtiny12
EXTRF
PORF
Reset Source
0
0
Watchdog Reset
1
0
External Reset
0
1
Power-on Reset
1
1
Power-on Reset
The MCU Status Register provides information on which reset source caused an MCU
reset.
Bit
7
6
5
4
3
2
1
0
$34
-
-
-
-
WDRF
BORF
EXTRF
PORF
Read/Write
R
R
R
R
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
MCUSR
See Bit Description
• Bit 7..4 - Res: Reserved Bits
These bits are reserved bits in the ATtiny12 and always read as zero.
• Bit 3 - WDRF: Watchdog Reset Flag
This bit is set if a watchdog reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.
• Bit 2 - BORF: Brown-out Reset Flag
This bit is set if a brown-out reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.
• Bit 1 - EXTRF: EXTernal Reset Flag
This bit is set if an external reset occurs. The bit is reset by a power-on reset, or by writing a logic zero to the flag.
• Bit 0 - PORF: Power-on Reset Flag
This bit is set if a power-on reset occurs. The bit is reset by writing a logic zero to the
flag.
To use the reset flags to identify a reset condition, the user should read and then reset
the MCUSR as early as possible in the program. If the register is cleared before another
reset occurs, the source of the reset can be found by examining the reset flags.
ATtiny12 Internal Voltage
Reference
ATtiny12 features an internal voltage reference with a nominal voltage of 1.22V. This
reference is used for Brown-out Detection, and it can be used as an input to the Analog
Comparator.
Voltage Reference Enable
Signals and Start-up Time
The voltage reference has a start-up time that may influence the way it should be used.
The maximum start-up time is 10µs. To save power, the reference is not always turned
on. The reference is on during the following situations:
24
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
1. When BOD is enabled (by programming the BODEN fuse)
2. When the bandgap reference is connected to the Analog Comparator (by setting
the AINBG bit in ACSR)
Thus, when BOD is not enabled, after setting the AINBG bit, the user must always allow
the reference to start up before the output from the Analog Comparator is used. The
bandgap reference uses approximately 10 µA, and to reduce power consumption in
Power-down mode, the user can turn off the reference when entering this mode.
Interrupt Handling
The ATtiny11/12 has two 8-bit Interrupt Mask control registers; GIMSK – General Interrupt Mask register and TIMSK – Timer/Counter Interrupt Mask register.
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 nested 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.
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.
Interrupt Response Time
The interrupt execution response for all the enabled AVR interrupts is 4 clock cycles
minimum. After the 4 clock cycles, 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. In
ATtiny12, if an interrupt occurs when the MCU is in Sleep mode, the interrupt response
time is increased by 4 clock cycles.
A return from an interrupt handling routine takes 4 clock cycles. During these 4 clock
cycles, the Program Counter (9 bits) is popped back from the Stack, and the I-flag in
SREG is set. When AVR exits from an interrupt, it will always return to the main program
and execute one more instruction before any pending interrupt is served.
General Interrupt Mask
Register – GIMSK
Bit
7
6
5
4
3
2
1
$3B
-
INT0
PCIE
-
-
-
-
0
-
Read/Write
R
R/W
R/W
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
GIMSK
25
1006D–AVR–07/03
• Bit 7 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny11/12 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 bits 1/0 (ISC01 and
ISC00) in the MCU general Control Register (MCUCR) define whether the external
interrupt is activated on rising or falling edge, on pin change, or low level of the INT0 pin.
Activity on the pin will cause an interrupt request even if INT0 is configured as an output.
The corresponding interrupt of External Interrupt Request 0 is executed from program
memory address $001. See also “External Interrupts.”
• Bit 5 - PCIE: Pin Change Interrupt Enable
When the PCIE bit is set (one) and the I-bit in the Status Register (SREG) is set (one),
the interrupt on pin change is enabled. Any change on any input or I/O pin will cause an
interrupt. The corresponding interrupt of Pin Change Interrupt Request is executed from
program memory address $002. See also “Pin Change Interrupt.”
• Bits 4..0 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11/12 and always read as zero.
General Interrupt Flag
Register – GIFR
Bit
7
6
5
4
3
2
1
$3A
-
INTF0
PCIF
-
-
-
-
0
-
Read/Write
R
R/W
R/W
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
GIFR
• Bit 7 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny11/12 and always reads as zero.
• Bit 6 - INTF0: External Interrupt Flag0
When an edge on the INT0 pin triggers an interrupt request, the corresponding interrupt
flag, INTF0 becomes set (one). If the I-bit in SREG and the corresponding interrupt
enable bit, INT0 bit in GIMSK, are set (one), the MCU will jump to the interrupt vector.
The flag is cleared when the interrupt routine is executed. Alternatively, the flag can be
cleared by writing a logical one to it. The flag is always cleared when INT0 is configured
as level interrupt.
• Bit 5 - PCIF: Pin Change Interrupt Flag
When an event on any input or I/O pin triggers an interrupt request, PCIF becomes set
(one). If the I-bit in SREG and the PCIE bit in GIMSK are set (one), the MCU will jump to
the interrupt vector at address $002. The flag is cleared when the interrupt routine is
executed. Alternatively, the flag can be cleared by writing a logical one to it.
• Bits 4..0 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11/12 and always read as zero.
Timer/Counter Interrupt Mask
Register – TIMSK
26
Bit
7
6
5
4
3
2
1
0
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
$39
-
-
-
-
-
-
TOIE0
-
Read/Write
R
R
R
R
R
R
R/W
R
Initial Value
0
0
0
0
0
0
0
0
TIMSK
• Bit 7..2 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11/12 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
$003) is executed if an overflow in Timer/Counter0 occurs, i.e., when the Overflow Flag
(Timer0) is set (one) in the Timer/Counter Interrupt Flag Register – TIFR.
• Bit 0 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny11/12 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 ATtiny11/12 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 logical one to the flag. When the SREG I-bit, TOIE0
(Tim er /Counter0 Overf low Interrupt Enabl e), and TO V0 are set (one), the
Timer/Counter0 Overflow interrupt is executed.
• Bit 0 - Res: Reserved bit
This bit is a reserved bit in the ATtiny11/12 and always reads as zero.
External Interrupt
The external interrupt is triggered by the INT0 pin. Observe that, if enabled, the interrupt
will trigger even if the INT0 pin is configured as an output. This feature provides a way of
generating a software interrupt. The external interrupt can be triggered by a falling or rising edge, a pin change, or a low level. This is set up as indicated in the specification for
the MCU Control Register – MCUCR. When the external interrupt is enabled and is configured as level triggered, the interrupt will trigger as long as the pin is held low.
The external interrupt is set up as described in the specification for the MCU Control
Register – MCUCR.
Pin Change Interrupt
The pin change interrupt is triggered by any change on any input or I/O pin. Change on
pins PB2..0 will always cause an interrupt. Change on pins PB5..3 will cause an interrupt if the pin is configured as input or I/O, as described in the section “Pin Descriptions”
on page 5. Observe that, if enabled, the interrupt will trigger even if the changing pin is
configured as an output. This feature provides a way of generating a software interrupt.
Also observe that the pin change interrupt will trigger even if the pin activity triggers
27
1006D–AVR–07/03
another interrupt, for example, the external interrupt. This implies that one external
event might cause several interrupts.
The values on the pins are sampled before detecting edges. If pin change interrupt is
enabled, pulses that last longer than one CPU clock period will generate an interrupt.
Shorter pulses are not guaranteed to generate an interrupt.
28
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
MCU Control Register –
MCUCR
The MCU Control Register contains control bits for general MCU functions.
Bit
7
6
5
4
3
2
1
0
$35
-
(PUD)
SE
SM
-
-
ISC01
ISC00
Read/Write
R
R(/W)
R/W
R/W
R
R
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Note:
MCUCR
The Pull-up Disable (PUD) bit is only available in ATtiny12.
• Bit 7 - Res: Reserved Bit
This bit is a reserved bit in the ATtiny11/12 and always reads as zero.
• Bit 6 - Res: Reserved Bit in ATtiny11
This bit is a reserved bit in the ATtiny11 and always reads as zero.
• Bit 6 - PUD: Pull-up Disable in ATtiny12
Setting this bit, disables all pull-ups on port B. If this bit is cleared, the pull-ups can be
individually enabled as described in section “I/O Port B” on page 43.
• 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 programmer’s 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” below.
• Bits 3, 2 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11/12 and always read as zero.
• Bits 1, 0 - ISC01, ISC00: Interrupt Sense Control0 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 are set. The following table shows how to set the ISC bits
to generate an external interrupt:
Table 13. Interrupt 0 Sense Control
ISC01
ISC00
Description
0
0
The low level of INT0 generates an interrupt request.
0
1
Any change on INT0 generates an interrupt request
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 that last 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
29
1006D–AVR–07/03
instruction to generate an interrupt. If enabled, a level-triggered interrupt will generate
an interrupt request as long as the pin is held low.
30
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Sleep Modes for the
ATtiny11
To enter the sleep modes, the SE bit in MCUCR must be set (one) and a SLEEP instruction must be executed. The SM bit in the MCUCR register selects which sleep mode
(Idle or Power-down) will be activated by the SLEEP instruction. 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. On wake-up from
Power Down Mode on pin change, two instruction cycles are executed before the pin
change interrupt flag is updated. During these cycles, the prosessor executes intructions, but the interrupt condition is not readable, and the interrupt routine has not startet
yet. The contents of the register file and 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 forces the MCU into 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
wake-up 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 forces the MCU into the Powerdown 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, or an pin change interrupt can wake up the
MCU.
Note that if a level-triggered or pin change interrupt is used for wake-up from powerdown, the changed level must be held for a time longer than the reset delay period of
tTOUT. Otherwise, the MCU will fail to wake up.
Sleep Modes for the
ATtiny12
To enter the sleep modes, the SE bit in MCUCR must be set (one) and a SLEEP instruction must be executed. The SM bit in the MCUCR register selects which sleep mode
(Idle or Power-down) will be activated by the SLEEP instruction. If an enabled interrupt
occurs while the MCU is in a sleep mode, the MCU awakes. The CPU is then halted for
four cycles, it executes the interrupt routine, and resumes execution from the instruction
following SLEEP. The contents of the register file and 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 forces the MCU into 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
wake-up 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.
Power-down Mode
When the SM bit is set (one), the SLEEP instruction forces the MCU into the Powerdown 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, or a pin change interrupt can wake up the
MCU.
31
1006D–AVR–07/03
Note that if a level triggered or pin change interrupt is used for wake-up from Powerdown Mode, the changed level must be held for a time to wake up the MCU. This makes
the MCU less sensitive to noise. The wake-up period is equal to the clock-counting part
of the reset period (See Table 9). The MCU will wake up from the power-down if the
input has the required level for two watchdog oscillator cycles. If the wake-up period is
shorter than two watchdog oscillator cycles, the MCU will wake up if the input has the
required level for the duration of the wake-up period. If the wake-up condition disappears before the wake-up period has expired, the MCU will wake up from power-down
without executing the corresponding interrupt. The period of the watchdog oscillator is
2.7 µs (nominal) at 3.0V and 25°C. The frequency of the watchdog oscillator is voltage
dependent as shown in the section “ATtiny11 Typical Characteristics” on page 60.
When waking up from Power-down Mode, there is a delay from the wake-up condition
occurs until the wake-up becomes effective. This allows the clock to restart and become
stable after having been stopped. The wake-up period is defined by the same CKSEL
fuses that define the reset time-out period.
ATtiny12 Calibrated
Internal RC Oscillator
Oscillator Calibration Register
– OSCCAL
In ATtiny12, the calibrated internal oscillator provides a fixed 1.2 MHz (nominal) clock at
5V and 25°C. This clock may be used as the system clock. See the section “Clock
Options” on page 5 for information on how to select this clock as the system clock. This
oscillator can be calibrated by writing the calibration byte to the OSCCAL register. When
this oscillator is used as the chip clock, the Watchdog Oscillator will still be used for the
Watchdog Timer and for the reset time-out. For details on how to use the pre-programmed calibration value, see the section “Calibration Byte in ATtiny12” on page 47. At
5V and 25oC, the pre-programmed calibration byte gives a frequency within ± 1% of the
nominal frequency.
Bit
7
6
5
4
3
2
1
0
$31
CAL7
CAL6
CAL5
CAL4
CAL3
CAL2
CAL1
CAL0
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
OSCCAL
• Bits 7..0 - CAL7..0: Oscillator Calibration Value
Writing the calibration byte to this address will trim the internal oscillator to remove process variations from the oscillator frequency. When OSCCAL is zero, the lowest
available frequency is chosen. Writing non-zero values to this register will increase the
frequency of the internal oscillator. Writing $FF to the register gives the highest available
frequency. The calibrated oscillator is used to time EEPROM access. If EEPROM is
written, do not calibrate to more than 10% above the nominal frequency. Otherwise, the
EEPROM write may fail. Table 14 shows the range for OSCCAL. Note that the oscillator
is intended for calibration to 1.2 MHz, thus tuning to other values is not guaranteed.
Table 14. Internal RC Oscillator Frequency Range
32
OSCCAL Value
Min Frequency
Max Frequency
$00
0.6 MHz
1.2 MHz
$7F
0.8 MHz
1.7 MHz
$FF
1.2 MHz
2.5 MHz
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Timer/Counter0
The ATtiny11/12 provides one general-purpose 8-bit Timer/Counter – Timer/Counter0.
The Timer/Counter0 has prescaling selection from the 10-bit prescaling timer. The
Timer/Counter0 can either be used as a timer with an internal clock timebase or as a
counter with an external pin connection that triggers the counting.
Timer/Counter Prescaler
Figure 23 shows the Timer/Counter prescaler.
Figure 23. Timer/Counter0 Prescaler
CK
CK/1024
CK/256
CK/64
CK/8
10-BIT T/C PRESCALER
T0
0
CS00
CS01
CS02
TIMER/COUNTER0 CLOCK SOURCE
TCK0
The four different prescaled selections are: CK/8, CK/64, CK/256 and CK/1024 where
CK is the oscillator clock. CK, external source and stop, can also be selected as clock
sources.
Figure 24 shows the block diagram for Timer/Counter0.
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 ensure 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.
33
1006D–AVR–07/03
Figure 24. Timer/Counter0 Block Diagram
T0
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 ATtiny11/12 and always read as zero.
• Bits 2,1,0 - CS02, CS01, CS00: Clock Select0, Bit 2,1 and 0
The Clock Select0 bits 2,1 and 0 define the prescaling source of Timer0.
Table 15. Clock 0 Prescale Select
34
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
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
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 PB2/(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 Counter 0 – 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 implemented 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.
35
1006D–AVR–07/03
Watchdog Timer
The Watchdog Timer is clocked from a separate on-chip oscillator. By controlling the
Watchdog Timer prescaler, the Watchdog reset interval can be adjusted as shown in
Table 16. See characterization data for typical values at other VCC levels. The WDR –
Watchdog Reset – instruction resets the Watchdog Timer. Eight different clock cycle
periods can be selected to determine the reset period. If the reset period expires without
another Watchdog reset, the ATtiny11/12 resets and executes from the reset vector. For
timing details on the Watchdog reset, refer to page 23.
To prevent unintentional disabling of the watchdog, a special turn-off sequence must be
followed when the watchdog is disabled. Refer to the description of the Watchdog Timer
Control Register for details.
Figure 25. Watchdog Timer
Oscillator
1 MHz at VCC = 5V
350 kHz at VCC = 3V
110 kHz at VCC = 2V
Watchdog Timer Control
Register – WDTCR
Bit
7
6
5
4
3
2
1
0
$21
-
-
-
WDTOE
WDE
WDP2
WDP1
WDP0
Read/Write
R
R
R
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
WDTCR
• Bits 7..5 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11/12 and will always read as zero.
• Bit 4 - WDTOE: Watchdog Turn-off Enable
This bit must be set (one) when the WDE bit is cleared. Otherwise, the watchdog will not
be disabled. Once set, hardware will clear this bit to zero after four clock cycles. Refer to
the description of the WDE bit for a watchdog disable procedure.
• 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. WDE can be cleared only when the
WDTOE bit is set(one). To disable an enabled watchdog timer, the following procedure
must be followed:
36
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
1. In the same operation, write a logical one to WDTOE and WDE. A logical one
must be written to WDE even though it is set to one before the disable operation
starts.
2. Within the next four clock cycles, write a logical 0 to WDE. This disables the
watchdog.
• Bits 2..0 - WDP2, WDP1, WDP0: Watchdog Timer Prescaler 2, 1 and 0
The WDP2, WDP1 and WDP0 bits determine the Watchdog Timer prescaling when the
Watchdog Timer is enabled. The different prescaling values and their corresponding
time-out periods are shown in Table 16.
Table 16. Watchdog Timer Prescale Select
Number of WDT
Oscillator cycles
Typical
Time-out at
VCC = 2.0V
Typical
Time-out at
VCC = 3.0V
Typical
Time-out at
VCC = 5.0V
WDP2
WDP1
WDP0
0
0
0
16K cycles
0.15s
47 ms
15 ms
0
0
1
32K cycles
0.30s
94 ms
30 ms
0
1
0
64K cycles
0.60s
0.19 s
60 ms
0
1
1
128K cycles
1.2s
0.38 s
0.12 s
1
0
0
256K cycles
2.4s
0.75 s
0.24 s
1
0
1
512K cycles
4.8s
1.5 s
0.49 s
1
1
0
1,024K cycles
9.6s
3.0 s
0.97 s
1
1
1
2,048K cycles
19s
6.0 s
1.9 s
Note:
The frequency of the Watchdog Oscillator is voltage dependent as shown in the section
“ATtiny11 Typical Characteristics” on page 60.
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 counting from zero.
To avoid unintentional MCU resets, the Watchdog Timer should be disabled or reset
before changing the Watchdog Timer Prescale Select.
37
1006D–AVR–07/03
ATtiny12 EEPROM
Read/Write Access
The EEPROM access registers are accessible in the I/O space.
The write access time is in the range of 3.1 - 6.8 ms, depending on the frequency of the
calibrated RC oscillator. See Table 17 for details. A self-timing function lets the user
software detect when the next byte can be written. A special EEPROM Ready interrupt
can be set to trigger when the EEPROM is ready to accept new data. The minimum voltage for writing to the EEPROM is 2.2V.
In order to prevent unintentional EEPROM writes, a two-state write procedure must be
followed. Refer to the description of the EEPROM Control Register 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
X
X
X
X
X
X
EEAR
The EEPROM Address Register – EEAR specifies the EEPROM address in the 64-byte
EEPROM space. The EEPROM data bytes are addressed linearly between 0 and 63.
During reset, the EEAR register is not cleared. Instead, the data in the register is kept.
EEPROM Data Register –
EEDR
Bit
7
6
5
4
3
2
1
0
$1D
MSB
LSB
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
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
-
-
-
-
EERIE
EEMWE
EEWE
EERE
Read/Write
R
R
R
R
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
X
0
EECR
• Bit 7..4 - Res: Reserved Bits
These bits are reserved bits in the ATtiny12 and will always read as zero.
• Bit 3 - EERIE: EEPROM Ready Interrupt Enable
When the I-bit in SREG and EERIE are set (one), the EEPROM Ready interrupt is
enabled. When cleared (zero), the interrupt is disabled. The EEPROM Ready interrupt
generates a constant interrupt when EEWE is cleared (zero).
38
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
• Bit 2 - EEMWE: EEPROM Master Write Enable
The EEMWE bit determines whether setting EEWE to one causes the EEPROM to be
written. When EEMWE is set (one), setting EEWE will write data to the EEPROM at the
selected address. If EEMWE is zero, setting EEWE will have no effect. When EEMWE
has been set (one) by software, hardware clears the bit to zero after four clock cycles.
See the description of the EEWE bit for a EEPROM write procedure.
• 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. The EEMWE bit must be set when the logical one is written to EEWE,
otherwise no EEPROM write takes place. The following procedure should be followed
when writing the EEPROM (the order of steps 2 and 3 is unessential):
1. Wait until EEWE becomes zero.
2. Write new EEPROM address to EEAR (optional).
3. Write new EEPROM data to EEDR (optional).
4. Write a logical one to the EEMWE bit in EECR (to be able to write a logical one
to the EEMWE bit, the EEWE bit must be written to zero in the same cycle).
5. Within four clock cycles after setting EEMWE, write a logical one to EEWE.
Caution: An interrupt between step 4 and step 5 will make the write cycle fail, since the
EEPROM Master Write Enable will time-out. 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 the four last steps to avoid these problems.
When the write access time 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.
The user should poll the EEWE bit before starting the read operation. If a write operation
is in progress when new data or address is written to the EEPROM I/O registers, the
write operation will be interrupted, and the result is undefined.
The calibrated oscillator is used to time EEPROM. In Table 17 the typical programming
time is listed for EEPROM access from the CPU.
Table 17. Typical EEPROM Programming Times
Parameter
EEPROM write
(from CPU)
Number of Calibrated
RC Oscillator Cycles
4096
Min Programming
Time
Max Programming
Time
3.1 ms
6.8 ms
39
1006D–AVR–07/03
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 can be done by enabling the internal Brown-out Detector (BOD) if
the operating speed matches the detection level. If not, an external low VCC
Reset Protection circuit can be applied.
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 can not be updated by the CPU, and will
not be subject to corruption.
40
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Analog Comparator
The Analog Comparator compares the input values on the positive input PB0 (AIN0) and
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 trigger a separate interrupt, exclusive
to the Analog Comparator. 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 26.
Figure 26. Analog Comparator Block Diagram.
INTERNAL
VOLTAGE
REFERENCE
(ATtiny12 ONLY)
AINBG
MUX
Analog Comparator Control
and Status Register – ACSR
Bit
7
6
5
4
3
2
1
0
$08
ACD
(AINBG)
ACO
ACI
ACIE
-
ACIS1
ACIS0
Read/Write
R/W
R(/W)
R
R/W
R/W
R
R/W
R/W
Initial Value
0
0
X
0
0
0
0
0
Note:
ACSR
AINBG is only available in ATtiny12.
• 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. 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 - AINBG: Analog Comparator Bandgap Select in ATtiny12
In ATtiny12, when this bit is set, a fixed bandgap voltage of 1.22 ± 0.05V replaces the
normal input to the positive input (AIN0) of the comparator. When this bit is cleared, the
normal input pin PB0 is applied to the positive input of the comparator.
• Bit 6- Res: Reserved Bit in ATtiny11
This bit is a reserved bit in the ATtiny11 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 ACI1 and ACI0. 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 execut41
1006D–AVR–07/03
ing the corresponding interrupt handling vector. Alternatively, ACI is cleared by writing a
logic one to the flag.
• 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 ATtiny11/12 and will always read as zero.
• Bits 1,0 - ACIS1, ACIS0: Analog Comparator Interrupt Mode Select
These bits determine which comparator events that trigger the Analog Comparator Interrupt. The different settings are shown in Table 18.
Table 18. 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.
Caution: Using the SBI or CBI instruction on bits other than ACI in this register will write
a one back into ACI if it is read as set, thus clearing the flag.
42
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
I/O Port B
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 is a 6-bit bi-directional I/O port.
Three I/O memory address locations are allocated for 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.
Ports PB5..3 have special functions as described in the section “Pin Descriptions” on
page 5. If PB5 is not configured as external reset, it is input with no pull-up. On
ATtiny12, it can also output a logical zero, acting as an open-drain output. Note that,
since PB5 only has one possible output value, the output functionality of this pin is controlled by the DDRB register alone. If PB4 and/or PB3 are not used for clock function,
they are I/O pins. All I/O pins have individually selectable pull-ups.
The Port B output buffers on PB0 to PB4 can sink 20 mA and thus drive LED displays
directly. On ATtiny12, PB5 can sink 12 mA. When pins PB0 to PB4 are used as inputs
and are externally pulled low, they will source current (IIL ) if the internal pull-ups are
activated.
The Port B pins with alternate functions are shown in Table 19:
Table 19. Port B Pins Alternate Functions
Port Pin
Alternate Functions
Device
AIN0 (Analog Comparator Positive Input)
ATtiny11/12
MOSI (Data Input Line for Memory Downloading)
ATtiny12
INT0 (External Interrupt0 Input)
ATtiny11/12
AIN1 (Analog Comparator Negative Input)
ATtiny11/12
MOSI (Data Output Line for Memory Downloading)
ATtiny12
T0 (Timer/Counter0 External Counter Input)
ATtiny11/12
SCK (Serial Clock Input for Serial Programming)
ATtiny12
PB3
XTAL1 (Oscillator Input)
ATtiny11/12
PB4
XTAL2 (Oscillator Output)
ATtiny11/12
PB5
RESET (External Reset Pin)
ATtiny11/12
PB0
PB1
PB2
When the pins PB2..0 are used for the alternate function, the DDRB and PORTB register has to be set according to the alternate function description. When PB5..3 are used
for alternate functions, the values in the corresponding DDRB and PORTB bits are
ignored.
43
1006D–AVR–07/03
Port B Data Register – PORTB
Port B Data Direction Register
– DDRB
Bit
7
6
5
4
3
2
1
0
$18
-
-
-
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
Read/Write
R
R
R
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
$17
-
-
(DDB5)
DDB4
DDB3
DDB2
DDB1
DDB0
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
Note:
Port B Input Pins Address –
PINB
PORTB
DDRB
DDB5 is only available in ATtiny12.
Bit
7
6
5
4
3
2
1
0
$16
-
-
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
Read/Write
R
R
R
R
R
R
R
R
Initial Value
0
0
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
The lowermost five 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) when the pin is configured as
an input pin, the MOS pull-up resistor is activated. On ATtiny12 this feature can be disabled by setting the Pull-up Disable (PUD) bit in the MCUCR register. To switch the pullup resistor off, the PORTBn can be cleared (zero), the pin can be configured as an output pin, or in ATtiny12, the PUD bit can be set. The port pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Table 20. DDBn Effects on Port B Pins
DDBn
PORTBn
I/O
Pull-up
Comment
0
0
Input
No
Tri-state (Hi-Z)
0
1
Input
Yes
PBn will source current if ext. pulled low. In ATtiny12
pull-ups can be disabled by setting the PUD bit.
1
0
Output
No
Push-pull Zero Output
1
1
Output
No
Push-pull One Output
n: 4,3…0, pin number.
Note that in ATtiny11, PB5 is input only. On ATtiny12, PB5 is input or open-drain output.
Because this pin is used for 12V programming, there is no ESD protection diode limiting
the voltage on the pin to VCC + 0.5V. Thus, special care should be taken to ensure that
the voltage on this pin does not rise above VCC + 1V during normal operation. This may
cause the MCU to reset or enter programming mode unintentionally.
44
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Alternate Functions of Port B
All port B pins are connected to a pin change detector that can trigger the pin change
interrupt. See “Pin Change Interrupt” on page 27 for details. In addition, Port B has the
following alternate functions:
• RESET - Port B, Bit 5
When the RSTDISBL fuse is unprogrammed, this pin serves as external reset. When
the RSTDISBL fuse is programmed, this pin is a general input pin. In ATtiny12, it is also
an open-drain output pin.
• XTAL2 - Port B, Bit 4
XTAL2, oscillator output. When this pin is not used for clock purposes, it is a general I/O
pin. Refer to section “Pin Descriptions” on page 5 for details.
• XTAL1 - Port B, Bit 3
XTAL1, oscillator or clock input. When this pin is not used for clock purposes, it is a general I/O pin. Refer to section “Pin Descriptions” on page 5 for details.
• T0/SCK - Port B, Bit 2
This pin can serve as the external counter clock input. See the timer/counter description
for further details. If external timer/counter clocking is selected, activity on this pin will
clock the counter even if it is configured as an output. In ATtiny12 and serial programming mode, this pin serves as the serial clock input, SCK.
• INT0/AIN1/MISO - Port B, Bit 1
This pin can serve as the external interrupt0 input. See the interrupt description for
details on how to enable this interrupt. Note that activity on this pin will trigger the interrupt even if the pin is configured as an output. This pin also serves as the negative input
of the on-chip Analog Comparator. In ATtiny12 and serial programming mode, this pin
serves as the serial data input, MISO.
• AIN0/MOSI - Port B, Bit 0
This pin also serves as the positive input of the on-chip Analog Comparator. In ATtiny12
and serial programming mode, this pin serves as the serial data output, MOSI.
During Power-down Mode, the schmitt triggers of the digital inputs are disconnected on
the Analog Comparator input pins. This allows an analog voltage close to VCC/2 to be
present during power-down without causing excessive power consumption.
45
1006D–AVR–07/03
Memory
Programming
Program (and Data)
Memory Lock Bits
The ATtiny11/12 MCU provides two lock bits which can be left unprogrammed (“1”) or
can be programmed (“0”) to obtain the additional features listed in Table 21. The lock
bits can only be erased with the Chip Erase command.
Table 21. 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 for ATtiny12) is
disabled.(1)
3
0
0
Same as mode 2, and verify is also disabled.
Note:
Fuse Bits in ATtiny11
Protection Type
1. In the High-voltage Serial Programming mode, further programming of the fuse bits
are also disabled. Program the fuse bits before programming the lock bits.
The ATtiny11 has five fuse bits, FSTRT, RSTDISBL and CKSEL2..0.
•
FSTRT: See Table 7, “Start-up Times for the ATtiny11 (VCC = 2.7V),” on page 18 for
which value to use. Default value is unprogrammed (“1”).
•
When RSTDISBL is programmed (“0”), the external reset function of pin PB5 is
disabled.(1) Default value is unprogrammed (“1”).
•
CKSEL2..0: See Table 3, “Device Clocking Options Select,” on page 5, for which
combination of CKSEL2..0 to use. Default value is “100”, internal RC oscillator.
The status of the fuse bits is not affected by Chip Erase.
Note:
Fuse Bits in ATtiny12
46
1. If the RSTDISBL Fuse is programmed, then the programming hardware should apply
+12V to PB5 while the ATtiny11 is in Power-on Reset. If not, the part can fail to enter
programming mode caused by drive contention on PB0.
The ATtiny12 has eight fuse bits, BODLEVEL, BODEN, SPIEN, RSTDISBL and
CKSEL3..0. All the fuse bits are programmable in both High-voltage and Low-voltage
Serial programming modes. Changing the fuses does not have any effect while in programming mode.
•
The BODLEVEL Fuse selects the Brown-out Detection level and changes the startup times. See “Brown-out Detection (ATtiny12)” on page 22. See Table 9, “ATtiny12
Clock Options and Start-up Times,” on page 20. Default value is programmed (“0”).
•
When the BODEN Fuse is programmed (“0”), the Brown-out Detector is enabled.
See “Brown-out Detection (ATtiny12)” on page 22. Default value is unprogrammed
(“1”).
•
When the SPIEN Fuse bit is programmed (“0”), Low-Voltage Serial Program and
Data Downloading is enabled. Default value is programmed (“0”). Unprogramming
this fuse while in the Low-Voltage Serial Programming mode will disable future insystem downloading attempts.
•
When the RSTDISBL Fuse is programmed (“0”), the external reset function of pin
PB5 is disabled.(1) Default value is unprogrammed (“1”). Programming this fuse
while in the Low-Voltage Serial Programming mode will disable future in-system
downloading attempts.
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
•
CKSEL3..0 fuses: See Table 3, “Device Clocking Options Select,” on page 5 and
Table 9, “ATtiny12 Clock Options and Start-up Times,” on page 20, for which
combination of CKSEL3..0 to use. Default value is “0010”, internal RC oscillator with
long start-up time.
The status of the fuse bits is not affected by Chip Erase.
Note:
Signature Bytes
1. If the RSTDISBL Fuse is programmed, then the programming hardware should apply
+12V to PB5 while the ATtiny12 is in Power-on Reset. If not, the part can fail to enter
programming mode caused by drive contention on PB0 and/or PB5.
All Atmel microcontrollers have a three-byte signature code which identifies the device.
The three bytes reside in a separate address space.
For the ATtiny11 they are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $90 (indicates 1 Kb Flash memory)
3. $002: $04 (indicates ATtiny11 device when signature byte $001 is $90)
For the ATtiny12(1) they are:
1. $000: $1E (indicates manufactured by Atmel)
2. $001: $90 (indicates 1 Kb Flash memory)
3. $002: $05 (indicates ATtiny12 device when signature byte $001 is $90)
Note:
Calibration Byte in
ATtiny12
1. When both lock bits are programmed (Lock mode 3), the Signature Bytes can not be
read in the Low-voltage Serial mode. Reading the Signature Bytes will return: $00,
$01 and $02.
The ATtiny12 has a one-byte calibration value for the internal RC oscillator. This byte
resides in the high byte of address $000 in the signature address space. During memory
programming, the external programmer must read this location and program its value
into a selected location in the normal Flash Program memory. At start-up, the user software must read this Flash location and write the value to the OSCCAL register.
Programming the Flash
and EEPROM
ATtiny11
Atmel’s ATtiny11 offers 1K bytes of Flash Program memory.
The ATtiny11 is shipped with the on-chip Flash Program memory array in the erased
state (i.e., contents = $FF) and ready to be programmed.
This device supports a High-voltage (12V) Serial programming mode. Only minor currents (<1 mA) are drawn from the +12V pin during programming.
The program memory array in the ATtiny11 is programmed byte-by-byte.
ATtiny12
Atmel’s ATtiny12 offers 1K bytes of in-system reprogrammable Flash Program memory
and 64 bytes of in-system reprogrammable EEPROM Data memory.
The ATtiny12 is shipped with the on-chip Flash Program 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) serial 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 Low-voltage Serial Programming mode
47
1006D–AVR–07/03
provides a convenient way to download program and data into the ATtiny12 inside the
user’s system.
The program and data memory arrays in the ATtiny12 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 Low-voltage Serial Programming mode.
ATtiny11/12
During programming, the supply voltage must be in accordance with Table 22.
Table 22. Supply Voltage during Programming
Part
High-voltage Serial
Programming
Low-voltage Serial Programming
High-voltage Serial Programming
ATtiny11L
Not applicable
4.5 - 5.5V
ATtiny11
Not applicable
4.5 - 5.5V
ATtiny12V
2.2 - 5.5V
4.5 - 5.5V
ATtiny12L
2.7 - 5.5V
4.5 - 5.5V
ATtiny12
4.0 - 5.5V
4.5 - 5.5V
This section describes how to program and verify Flash Program memory, EEPROM
Data memory (ATtiny12), lock bits and fuse bits in the ATtiny11/12.
Figure 27. High-voltage Serial Programming
11.5 - 12.5V
4.5 - 5.5V
ATtiny
SERIAL CLOCK INPUT
PB5 (RESET)
VCC
PB3 (XTAL1)
PB2
SERIAL DATA OUTPUT
PB1
SERIAL INSTR. INPUT
PB0
SERIAL DATA INPUT
GND
48
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
High-voltage Serial
Programming Algorithm
To program and verify the ATtiny11/12 in the High-voltage Serial Programming mode,
the following sequence is recommended (See instruction formats in Table 23):
1. Power-up sequence: Apply 4.5 - 5.5V between VCC and GND. Set PB5 and PB0
to “0” and wait at least 100 ns. Toggle PB3 at least four times with minimum 100
ns pulse-width. Set PB3 to “0”. Wait at least 100 ns. Apply 12V to PB5 and wait
at least 100 ns before changing PB0. Wait 8 µs before giving any instructions.
2. The Flash array is programmed one byte at a time by supplying first the address,
then the low and high data byte. The write instruction is self-timed, wait until the
PB2 (RDY/BSY) pin goes high.
3. The EEPROM array (ATtiny12 only) is programmed one byte at a time by supplying first the address, then the data byte. The write instruction is self-timed, wait
until the PB2 (RDY/BSY) pin goes high.
4. Any memory location can be verified by using the Read instruction which returns
the contents at the selected address at serial output PB2.
5. Power-off sequence:Set PB3 to “0”.
Set PB5 to “1”.
Turn VCC power off.
When writing or reading serial data to the ATtiny11/12, data is clocked on the rising
edge of the serial clock, see Figure 28, Figure 29 and Table 24 for details.
49
1006D–AVR–07/03
Figure 28. High-voltage Serial Programming Waveforms
SERIAL DATA INPUT
PB0
MSB
LSB
SERIAL INSTR. INPUT
PB1
MSB
LSB
SERIAL DATA OUTPUT
PB2
SERIAL CLOCK INPUT
XTAL1/PB3
MSB
0
LSB
1
2
3
4
5
6
7
8
9
10
Table 23. High-voltage Serial Programming Instruction Set for ATtiny11/12
Instruction Format
Instruction
Instr.1
Instr.2
Instr.3
Instr.4
PB0
PB1
0_1000_0000_00
0_0100_1100_00
0_0000_0000_00
0_0110_0100_00
0_0000_0000_00
0_0110_1100_00
0_0000_0000_00
0_0100_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
PB0
0_0001_0000_00
0_0000_000a_00
0_bbbb_bbbb_00
PB1
PB2
0_0100_1100_00
x_xxxx_xxxx_xx
0_0001_1100_00
x_xxxx_xxxx_xx
0_0000_1100_00
x_xxxx_xxxx_xx
PB0
Write Flash Low
PB1
byte
PB2
0_ i i i i_i i i i _00
0_0000_0000_00
0_0000_0000_00
0_0010_1100_00
0_0110_0100_00
0_0110_1100_00
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
0_0000_0000_00
PB0
0_ i i i i_i i i i _00
0_0000_0000_00
0_0000_0000_00
PB1
0_0011_1100_00
0_0111_0100_00
0_0111_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
0_0000_0000_00
PB0
PB1
0_0000_0010_00
0_0100_1100_00
0_0000_000a_00
0_0001_1100_00
0_bbbb_bbbb_00
0_0000_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
PB0
0_0000_0000_00
0_0000_0000_00
PB1
0_0110_1000_00
0_0110_1100_00
PB2
x_xxxx_xxxx_xx
o_oooo_ooox_xx
PB0
PB1
PB2
0_0000_0000_00
0_0000_0000_00
0_0111_1000_00
x_xxxx_xxxx_xx
0_0111_1100_00
o_oooo_ooox_xx
Write EEPROM PB0
PB1
Low Address
(ATtiny12)
PB2
0_0001_0001_00
0_00bb_bbbb_00
0_0100_1100_00
0_0000_1100_00
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
Chip Erase
Write Flash
High and Low
Address
Write Flash
High byte
Read Flash
High and Low
Address
Read Flash
Low byte
Read Flash
High byte
PB0
Write EEPROM
PB1
byte (ATtiny12)
PB2
Read EEPROM PB0
Low Address
PB1
(ATtiny12)
PB2
50
Operation Remarks
Wait after Instr.4 until PB2 goes
high for the Chip Erase cycle to
finish.
Repeat Instr.2 for a new 256 byte
page. Repeat Instr.3 for each new
address.
Wait after Instr.3 until PB2 goes
high. Repeat Instr.1, Instr. 2 and
Instr.3 for each new address.
Wait after Instr.3 until PB2 goes
high. Repeat Instr.1, Instr. 2 and
Instr.3 for each new address.
Repeat Instr.2 and Instr.3 for each
new address.
Repeat Instr.1 and Instr.2 for each
new address.
Repeat Instr.1 and Instr.2 for each
new address.
Repeat Instr.2 for each new
address.
0_ i i i i_i i i i _00
0_0000_0000_00
0_0000_0000_00
0_0010_1100_00
0_0110_0100_00
0_0110_1100_00
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
0_0000_0000_00
0_0000_0011_00
0_00bb_bbbb_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_1100_00
x_xxxx_xxxx_xx
Wait after Instr.3 until PB2 goes
high
Repeat Instr.2 for each new
address.
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Table 23. High-voltage Serial Programming Instruction Set for ATtiny11/12 (Continued)
Instruction Format
Instruction
Instr.1
Instr.2
PB0
Read EEPROM
PB1
byte (ATtiny12)
PB2
0_0000_0000_00
0_0000_0000_00
0_0110_1000_00
0_0110_1100_00
x_xxxx_xxxx_xx
o_oooo_ooox_xx
PB0
PB1
0_0100_0000_00
0_0100_1100_00
0_0007_6543_00
0_0010_1100_00
0_0000_0000_00
0_0110_0100_00
0_0000_0000_00
0_0110_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
PB0
0_0100_0000_00
0_CBA9_8543_00
0_0000_0000_00
0_0000_0000_00
PB1
PB2
0_0100_1100_00
x_xxxx_xxxx_xx
0_0010_1100_00
x_xxxx_xxxx_xx
0_0110_0100_00
x_xxxx_xxxx_xx
0_0110_1100_00
x_xxxx_xxxx_xx
PB0
0_0010_0000_00
0_0000_0210_00
0_0000_0000_00
0_0000_0000_00
PB1
PB2
0_0100_1100_00
x_xxxx_xxxx_xx
0_0010_1100_00
x_xxxx_xxxx_xx
0_0110_0100_00
x_xxxx_xxxx_xx
0_0110_1100_00
0_0000_0000_00
PB0
0_0000_0100_00
0_0000_0000_00
0_0000_0000_00
PB1
0_0100_1100_00
0_0110_1000_00
0_0110_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xx76_543x_xx
PB0
PB1
0_0000_0100_00
0_0100_1100_00
0_0000_0000_00
0_0110_1000_00
0_0000_0000_00
0_0110_1100_00
PB2
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
C_BA98_543x_xx
PB0
0_0000_0100_00
0_0000_0000_00
0_0000_0000_00
PB1
PB2
0_0100_1100_00
x_xxxx_xxxx_xx
0_0111_1000_00
x_xxxx_xxxx_xx
0_0111_1100_00
x_xxxx_21xx_xx
PB0
Read Signature
PB1
Bytes
PB2
0_0000_1000_00
0_0000_00bb_00
0_0000_0000_00
0_0000_0000_00
0_0100_1100_00
x_xxxx_xxxx_xx
0_0000_1100_00
x_xxxx_xxxx_xx
0_0110_1000_00
x_xxxx_xxxx_xx
0_0110_1100_00
o_oooo_ooox_xx
PB0
Read
Calibration Byte PB1
(ATtiny12)
PB2
0_0000_1000_00
0_0000_0000_00
0_0000_0000_00
0_0000_0000_00
0_0100_1100_00
0_0000_1100_00
0_0111_1000_00
0_0111_1100_00
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
x_xxxx_xxxx_xx
o_oooo_ooox_xx
Write Fuse bits
(ATtiny11)
Write Fuse bits
(ATtiny12)
Write Lock bits
Read Fuse bits
(ATtiny11)
Read Fuse bits
(ATtiny12)
Read Lock bits
Note:
Instr.3
Instr.4
Operation Remarks
Repeat Instr.2 for each new
address
Wait tWLWH_PFB after Instr.3 for the
Write fuse bits cycle to finish. Write
7 - 3 = “0” to program the fuse bit.
Wait after Instr.4 until PB2 goes
high. Write C - A, 9, 8, 5 - 3 = “0” to
program the fuse bit.
Wait after Instr.4 until PB2 goes
high. Write 2, 1 = “0” to program
the lock bit.
Reading 7 - 3 = “0” means the fuse
bit is programmed.
Reading C - A, 9, 8, 5 - 3 = “0”
means the fuse bit is programmed.
Reading 2, 1 = “0” means the lock
bit is programmed.
Repeat Instr.2 - Instr.4 for each
signature byte address
a = address high bits
b = address low bits
i = data in
o = data out
x = don’t care
1 = Lock Bit1
2 = Lock Bit2
3 = CKSEL0 Fuse
4 = CKSEL1 Fuse
5 = CKSEL2 Fuse
9, 6 = RSTDISBL Fuse
7 = FSTRT Fuse
8 = CKSEL3 Fuse
A = SPIEN Fuse
B = BODEN Fuse
C = BODLEVEL Fuse
51
1006D–AVR–07/03
High-voltage Serial
Programming
Characteristics
Figure 29. High-voltage Serial Programming Timing
SDI (PB0), SII (PB1)
tIVSH
SCI (PB3)
tSHIX
tSLSH
tSHSL
SDO (PB2)
tSHOV
Table 24. High-voltage Serial Programming Characteristics TA = 25°C ± 10%, VCC =
5.0V ± 10% (Unless otherwise noted)
Symbol
Low-voltage Serial
Downloading (ATtiny12
only)
Parameter
Min
Typ
Max
Units
tSHSL
SCI (PB3) Pulse Width High
100
ns
tSLSH
SCI (PB3) Pulse Width Low
100
ns
tIVSH
SDI (PB0), SII (PB1) Valid to SCI (PB3) High
50
ns
tSHIX
SDI (PB0), SII (PB1) Hold after SCI (PB3) High
50
ns
tSHOV
SCI (PB3) High to SDO (PB2) Valid
10
16
32
ns
tWLWH_PFB
Wait after Instr. 3 for Write Fuse Bits
1.7
2.5
3.4
ms
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 30. After RESET is set low, the Programming Enable instruction needs to be executed first before program/erase instructions can be executed.
Figure 30. Serial Programming and Verify
2.2 - 5.5V
ATtiny12
GND
PB5 (RESET)
GND
52
VCC
PB2
SCK
PB1
MISO
PB0
MOSI
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
If the chip Erase command in Low-voltage Serial Programming is executed only once,
one data byte may be written to the flash after erase. Using the following algorithm guarantees that the flash will be erased:
•
Execute a chip erase command
•
Write $FF to address $00 in the flash
•
Execute a second chip erase command
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 program memory and $000 to $03F for EEPROM memory.
The device can be clocked by any clock option during Low-voltage Serial Programming.
The minimum low and high periods for the serial clock (SCK) input are defined as
follows:
Low: > 2 MCU clock cycles
High: > 2 MCU clock cycles
Low-voltage Serial
Programming Algorithm
When writing serial data to the ATtiny12, data is clocked on the rising edge of SCK.
When reading data from the ATtiny12, data is clocked on the falling edge of SCK. See
Figure 31, Figure 32 and Table 26 for timing details. To program and verify the ATtiny12
in the serial programming mode, the following sequence is recommended (See 4 byte
instruction formats in Table 25):
1. Power-up sequence:
Apply power between VCC and GND while RESET and SCK are set to “0”. In accordance with the setting of CKSEL fuses, apply a crystal/resonator, external clock or
RC network, or let the device run on the internal RC oscillator. In some systems, the
programmer can not guarantee that SCK is held low during power-up. In this case,
RESET must be given a positive pulse of at least two MCU cycles duration 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 (PB0) pin.
3. The serial programming instructions will not work if the communication is out of
synchronization. When in sync, the second byte ($53) will echo back when issuing the third byte of the Programming Enable instruction. Whether the echo is
correct or not, all 4 bytes of the instruction must be transmitted. If the $53 did not
echo back, give SCK a positive pulse and issue a new Programming Enable
instruction. If the $53 is not seen within 32 attempts, there is no functional device
connected.
4. 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 27 on page 56 for tWD_ERASE value.
5. 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. Use
Data Polling to detect when the next byte in the Flash or EEPROM can be written. If polling is not used, wait tWD_FLASH or tWD_EEPROM before transmitting the
53
1006D–AVR–07/03
next instruction. See Table 28 on page 56 for tWD_FLASH and tWD_EEPROM values. In
an erased device, no $FFs in the data file(s) needs to be programmed.
6. Any memory location can be verified by using the Read instruction which returns
the content at the selected address at the serial output MISO (PB1) pin.
7. At the end of the programming session, RESET can be set high to commence
normal operation.
8. Power-off sequence (if needed):
Set XTAL1 to “0” (if external clocking is used).
Set RESET to “1”.
Turn VCC power off.
Data Polling
When a byte is being programmed into the Flash or EEPROM, 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_FLASH or tWD_EEPROM 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. This does not apply if the
EEPROM is reprogrammed without chip-erasing the device. In that case, data polling
cannot be used for the value $FF, and the user will have to wait at least t WD_EEPROM
before programming the next byte. See Table 28 for tWD_FLASH and tWD_EEPROM values.
Figure 31. Low-voltage Serial Programming Waveforms
SERIAL DATA INPUT
PB0(MOSI)
MSB
LSB
SERIAL DATA OUTPUT
PB1(MISO)
MSB
LSB
SERIAL CLOCK INPUT
PB2(SCK)
54
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Table 25. Low-voltage Serial Programming Instruction Set
Instruction Format
Instruction
Byte 1
Byte 2
Byte 3
Byte4
1010 1100
0101 0011
xxxx xxxx
xxxx xxxx
Enable serial programming while
RESET is low.
1010 1100
100x xxxx
xxxx xxxx
xxxx xxxx
Chip erase Flash and EEPROM
memory arrays.
0010 H000
xxxx xxxa
bbbb bbbb
oooo oooo
Read H (high or low) data o from
program memory at word address
a:b.
0100 H000
xxxx xxxa
bbbb bbbb
iiii iiii
Write H (high or low) data i to
program memory at word address
a:b.
Read EEPROM
Memory
1010 0000
xxxx xxxx
xxbb bbbb
oooo oooo
Read data o from EEPROM memory
at address b.
Write EEPROM
Memory
1100 0000
xxxx xxxx
xxbb bbbb
iiii iiii
Write data i to EEPROM memory at
address b.
1010 1100
1111 1211
xxxx xxxx
xxxx xxxx
Write lock bits. Set bits 1,2 = “0” to
program lock bits.
0101 1000
xxxx xxxx
xxxx xxxx
xxxx x21x
Read lock bits. “0” = programmed, “1”
= unprogrammed.
Read Signature Bytes
0011 0000
xxxx xxxx
0000 00bb
oooo oooo
Read signature byte o at address b.(1)
Read Calibration Byte
0011 1000
xxxx xxxx
0000 0000
oooo oooo
1010 1100
101x xxxx
xxxx xxxx
A987 6543
Set bits A, 9 - 3 = “0” to program, “1”
to unprogram.
0101 0000
xxxx xxxx
xxxx xxxx
A987 6543
Read fuse bits. “0” = programmed, “1”
= unprogrammed.
Programming Enable
Chip Erase
Read Program Memory
Write Program Memory
Write Lock Bits
Read Lock Bits
Write Fuse Bits
Read Fuse Bits
Operation
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
3 = CKSEL0 Fuse
4 = CKSEL1 Fuse
5 = CKSEL2 Fuse
6 = CKSEL3 Fuse
7 = RSTDISBL Fuse
8 = SPIEN Fuse
9 = BODEN Fuse
A = BODLEVEL Fuse
Note:
1. The signature bytes are not readable in Lock mode 3, i.e. both lock bits programmed.
55
1006D–AVR–07/03
Low-voltage Serial
Programming
Characteristics
Figure 32. Low-voltage Serial Programming Timing
MOSI
tOVSH
SCK
tSHOX
tSLSH
tSHSL
MISO
tSLIV
Table 26. Low-voltage Serial Programming Characteristics TA = -40°C to 85°C,
VCC = 2.2 - 5.5V (Unless otherwise noted)
Symbol
Parameter
1/tCLCL
Oscillator Frequency (VCC = 2.2 - 2.7V)
tCLCL
Oscillator Period (VCC = 2.2 - 2.7V)
1/tCLCL
Oscillator Frequency (VCC = 2.7 - 4.0V)
tCLCL
Oscillator Period (VCC = 2.7 - 4.0V)
1/tCLCL
Oscillator Frequency (VCC = 4.0 - 5.5V)
tCLCL
Oscillator Period (VCC = 4.0 - 5.5V)
tSHSL
Min
Typ
0
Max
Units
1
MHz
1000
ns
0
4
250
MHz
ns
0
8
MHz
125
ns
SCK Pulse Width High
2 tCLCL
ns
tSLSH
SCK Pulse Width Low
2 tCLCL
ns
tOVSH
MOSI Setup to SCK High
tCLCL
ns
tSHOX
MOSI Hold after SCK High
2 tCLCL
ns
tSLIV
SCK Low to MISO Valid
10
16
32
ns
Table 27. Minimum Wait Delay after the Chip Erase Instruction
Symbol
Minimum Wait Delay
tWD_ERASE
6.8 ms
Table 28. Minimum Wait Delay after Writing a Flash or EEPROM Location
56
Symbol
Minimum Wait Delay
tWD_FLASH
3.4 ms
tWD_EEPROM
6.8 ms
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Electrical Characteristics
Absolute Maximum Ratings
Operating Temperature .................................. -55°C to +125°C
*NOTICE:
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
Stresses beyond those ratings 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.
Maximum Operating Voltage ............................................ 6.0V
DC Current per I/O Pin ............................................... 40.0 mA
DC Current VCC and GND Pins................................ 100.0 mA
DC Characteristics – Preliminary Data
TA = -40°C to 85°C, VCC = 2.7V to 5.5V for ATtiny11, VCC = 1.8V to 5.5V for ATtiny12 (Unless otherwise noted)
Symbol
Parameter
Condition
Min
VIL
Input Low Voltage
Except (XTAL)
-0.5
0.3 VCC(1)
V
-0.5
(1)
V
(2)
VCC + 0.5
V
VIL1
Input Low Voltage
XTAL
Typ
Max
0.1 VCC
Units
VIH
Input High Voltage
Except (XTAL, RESET)
0.6 VCC
VIH1
Input High Voltage
XTAL
0.7 VCC (2)
VCC + 0.5
V
VIH2
Input High Voltage
RESET
0.85 VCC(2)
VCC + 0.5
V
IOL = 20 mA, VCC = 5V
IOL = 10 mA, VCC = 3V
0.6
0.5
V
V
0.6
0.5
V
V
(3)
VOL
Output Low Voltage
Port B
VOL
Output Low Voltage
PB5 (ATtiny12)
IOL = 12 mA, VCC = 5V
IOL = 6 mA, VCC = 3V
VOH
Output High Voltage(4)
Port B
IOH = -3 mA, VCC = 5V
IOH = -1.5 mA, VCC = 3V
IIL
Input Leakage Current
I/O Pin
VCC = 5.5V, Pin Low
(Absolute value)
8.0
µA
IIH
Input Leakage Current
I/O Pin
VCC = 5.5V, Pin High
(Absolute value)
8.0
µA
RI/O
I/O Pin Pull-Up
122
kΩ
4.3
2.3
35
V
V
57
1006D–AVR–07/03
DC Characteristics – Preliminary Data (Continued)
TA = -40°C to 85°C, VCC = 2.7V to 5.5V for ATtiny11, VCC = 1.8V to 5.5V for ATtiny12 (Unless otherwise noted)
Symbol
ICC
Parameter
Power Supply Current
Condition
Max
Units
Active 1 MHz, VCC = 3V
(ATtiny12V)
1.0
mA
Active 2 MHz, VCC = 3V
(ATtiny11L)
2.0
mA
Active 4 MHz, VCC = 3V
(ATtiny12L)
2.5
mA
Active 6 MHz, VCC = 5V
(ATtiny11)
10
mA
Active 8 MHz, VCC = 5V
(ATtiny12)
10
mA
Idle 1 MHz, VCC = 3V
(ATtiny12V)
0.4
mA
Idle 2 MHz, VCC = 3V
(ATtiny11L)
0.5
mA
Idle 4 MHz, VCC = 3V
(ATtiny12L)
1.0
mA
Idle 6 MHz, VCC = 5V
(ATtiny11)
2.0
mA
Idle 8 MHz, VCC = 5V
(ATtiny12)
3.5
mA
9.0
15
µA
Power Down(5), VCC = 3V.
WDT disabled (ATtiny12)
<1
2
µA
Power Down(5), VCC = 3V.
WDT disabled (ATtiny11)
<1
5
µA
40
mV
50
nA
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
58
Typ
Power Down(5), VCC = 3V,
WDT enabled
VACIO
Notes:
Min
-50
750
500
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 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 conditions.
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 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 1.5V. (On ATtiny12: only with BOD disabled)
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
External Clock Drive
Waveforms
Figure 33. External Clock
VIH1
VIL1
External Clock Drive ATtiny11
VCC = 2.7V to 4.0V
Symbol
Parameter
1/tCLCL
Oscillator Frequency
VCC = 4.0V to 5.5V
Min
Max
Min
Max
Units
0
2
0
6
MHz
tCLCL
Clock Period
500
167
ns
tCHCX
High Time
200
67
ns
tCLCX
Low Time
200
67
ns
tCLCH
Rise Time
1.6
0.5
µs
tCHCL
Fall Time
1.6
0.5
µs
External Clock Drive ATtiny12
VCC = 1.8V to
2.7V
VCC = 2.7V to
4.0V
VCC = 4.0V to
5.5V
Symbol
Parameter
Min
Max
Min
Max
Min
Max
Units
1/tCLCL
Oscillator
Frequency
0
1.2
0
4
0
8
MHz
tCLCL
Clock Period
833
250
125
ns
tCHCX
High Time
333
100
50
ns
tCLCX
Low Time
333
100
50
ns
tCLCH
Rise Time
1.6
1.6
0.5
µs
tCHCL
Fall Time
1.6
1.6
0.5
µs
Table 29. External RC Oscillator, Typical Frequencies
Note:
R [kΩ]
C [pF]
f
100
70
100 kHz
31.5
20
1.0 MHz
6.5
20
4.0 MHz
R should be in the range 3-100 kΩ, and C should be at least 20 pF. The C values given in
the table includes pin capacitance. This will vary with package type.
59
1006D–AVR–07/03
ATtiny11 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 railto-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 34. Active Supply Current vs. Frequency
ACTIVE SUPPLY CURRENT vs. FREQUENCY
TA = 25˚C
18
VCC = 6V
16
VCC = 5.5V
14
VCC = 5V
12
ICC (mA)
VCC = 4.5V
10
VCC = 4V
8
VCC = 3.6V
6
VCC = 3.3V
4
VCC = 3.0V
VCC = 2.7V
2
VCC = 2.4V
0
VCC = 2.1V
VCC = 1.8V
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Frequency (MHz)
60
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 35. Active Supply Current vs. VCC
ACTIVE SUPPLY CURRENT vs. Vcc
FREQUENCY = 4 MHz
10
9
8
TA = 25˚C
7
TA = 85˚C
ICC (mA)
6
5
4
3
2
1
0
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
Figure 36. Active Supply Current vs. VCC, Device Clocked by Internal Oscillator
ACTIVE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 1.0MHz INTERNAL RC OSCILLATOR
6
5
TA = 25˚C
4
I cc(mA)
TA = 85˚C
3
2
1
0
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
61
1006D–AVR–07/03
Figure 37. Active Supply Current vs. VCC, Device Clocked by External 32kHz Crystal
ACTIVE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 32KHz CRYSTAL
5
4.5
4
TA = 25˚C
3.5
TA = 85˚C
I cc(mA)
3
2.5
2
1.5
1
0.5
0
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 38. Idle Supply Current vs. Frequency
IDLE SUPPLY CURRENT vs. FREQUENCY
TA = 25˚C
5
VCC = 6V
4.5
4
VCC = 5.5V
3.5
VCC = 5V
ICC (mA)
3
VCC = 4.5V
2.5
VCC = 4V
2
VCC = 3.6V
1.5
VCC = 3.3V
1
VCC = 3.0V
VCC = 2.7V
0.5
0
0
VCC = 2.4V
VCC = 2.1V
VCC = 1.8V
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Frequency (MHz)
62
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 39. Idle Supply Current vs. VCC
IDLE SUPPLY CURRENT vs. Vcc
FREQUENCY = 4 MHz
3
TA = 25˚C
2
ICC (mA)
TA = 85˚C
2
1
1
0
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
Figure 40. Idle Supply Current vs. VCC, Device Clocked by Internal Oscillator
IDLE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 1.0MHz INTERNAL RC OSCILLATOR
0.35
0.3
TA = 25˚C
0.25
TA = 85˚C
I cc(mA)
0.2
0.15
0.1
0.05
0
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
63
1006D–AVR–07/03
Figure 41. Idle Supply Current vs. VCC, Device Clocked by External 32kHz Crystal
IDLE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 32KHz CRYSTAL
25
20
TA = 25˚C
TA = 85˚C
I cc(µA)
15
10
5
0
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 42. Power-down Supply Current vs. VCC
POWER-DOWN SUPPLY CURRENT vs. Vcc
WATCHDOG TIMER DISABLED
9
TA = 85˚C
8
ICC (µA)
7
6
5
4
3
2
1
TA = 25˚C
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
64
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 43. Power-down Supply Current vs. VCC
POWER-DOWN SUPPLY CURRENT vs. Vcc
WATCHDOG TIMER ENABLED
90
80
70
I CC (µA)
60
TA = 85˚C
TA = 25˚C
50
40
30
20
10
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
Figure 44. Analog Comparator Current vs. VCC
ANALOG COMPARATOR CURRENT vs. Vcc
1
0.9
0.8
TA = 25˚C
I CC (mA)
0.7
TA = 85˚C
0.6
0.5
0.4
0.3
0.2
0.1
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
65
1006D–AVR–07/03
Analog comparator offset voltage is measured as absolute offset.
Figure 45. 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
3.5
4
4.5
5
Common Mode Voltage (V)
Figure 46. 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)
66
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 47. Analog Comparator Input Leakage Current
ANALOG COMPARATOR INPUT LEAKAGE CURRENT
VCC = 6V
TA = 25˚C
60
50
IACLK (nA)
40
30
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)
Figure 48. Watchdog Oscillator Frequency vs. VCC
WATCHDOG OSCILLATOR FREQUENCY vs. Vcc
1600
1400
TA = 25˚C
1200
TA = 85˚C
FRC (kHz)
1000
800
600
400
200
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
67
1006D–AVR–07/03
Sink and source capabilities of I/O ports are measured on one pin at a time.
Figure 49. 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
VOP (V)
3
3.5
4
4.5
5
Figure 50. 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
I OP (µA)
20
15
10
5
0
0
0.5
1
1.5
2
2.5
3
VOP (V)
68
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 51. I/O Pin Sink Current vs. Output Voltage
I/O PIN SINK CURRENT vs. OUTPUT VOLTAGE
VCC = 5V
80
70
TA = 25˚C
60
I OL (mA)
50
40
TA = 85˚C
30
20
10
0
0
0.5
1
1.5
2
2.5
3
VOL (V)
Figure 52. I/O Pin Source Current vs. Output Voltage
I/O PIN SOURCE CURRENT vs. OUTPUT VOLTAGE
VCC = 5V
18
TA = 25˚C
16
14
TA = 85˚C
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)
69
1006D–AVR–07/03
Figure 53. I/O Pin Sink Current vs. Output Voltage
I/O PIN SINK CURRENT vs. OUTPUT VOLTAGE
VCC = 2.7V
30
TA = 25˚C
25
20
I OL (mA)
TA = 85˚C
15
10
5
0
0
0.5
1
1.5
2
VOL (V)
Figure 54. I/O Pin Source Current vs. Output Voltage
I/O PIN SOURCE CURRENT vs. OUTPUT VOLTAGE
VCC = 2.7V
6
TA = 25˚C
5
4
I OH (mA)
TA = 85˚C
3
2
1
0
0
0.5
1
1.5
2
2.5
3
VOH (V)
70
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 55. 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 56. I/O Pin Input Hysteresis vs. VCC
I/O PIN INPUT HYSTERESIS vs. Vcc
TA = 25˚C
0.18
Input Hysteresis (V)
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
2.7
4.0
5.0
VCC
71
1006D–AVR–07/03
ATtiny12 Typical
Characteristics
The following charts show typical behavior. These data are characterized, but not
tested. 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 57. Active Supply Current vs. VCC, Device Clocked by Internal Oscillator
ACTIVE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 1.2MHz INTERNAL RC OSCILLATOR
1.8
1.6
TA = 85˚C
1.4
TA = 25˚C
I cc(mΑ)
1.2
1
0.8
0.6
0.4
0.2
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
72
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 58. Active Supply Current vs. VCC, Device Clocked by External 32kHz Crystal
ACTIVE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 32KHz CRYSTAL
140
120
TA = 85˚C
100
I cc(µΑ)
TA = 25˚C
80
60
40
20
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Figure 59. Idle Supply Current vs. VCC, Device Clocked by Internal Oscillator
IDLE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 1.2MHz INTERNAL RC OSCILLATOR
0.8
0.7
TA = 25˚C
0.6
TA = 85˚C
I cc(mΑ)
0.5
0.4
0.3
0.2
0.1
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
73
1006D–AVR–07/03
Figure 60. Idle Supply Current vs. VCC, Device Clocked by External 32kHz Crystal
IDLE SUPPLY CURRENT vs. Vcc
DEVICE CLOCKED BY 32KHz CRYSTAL
30
25
I cc(µΑ)
20
15
10
TA = 85˚C
TA = 25˚C
5
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Vcc(V)
Analog Comparator offset voltage is measured as absolute offset.
Figure 61. 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
3.5
4
4.5
5
Common Mode Voltage (V)
74
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 62. Analog Comparator Offset Voltage vs. Common Mode Voltage
ANALOG COMPARATOR OFFSET VOLTAGE vs.
COMMON MODE VOLTAGE
VCC = 2.7V
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 63. Analog Comparator Input Leakage Current
ANALOG COMPARATOR INPUT LEAKAGE CURRENT
VCC = 6V
TA = 25˚C
60
50
I ACLK (nA)
40
30
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)
75
1006D–AVR–07/03
Figure 64. Calibrated RC Oscillator Frequency vs. VCC
CALIBRATED RC OSCILLATOR FREQUENCY vs.
OPERATING VOLTAGE
1.22
TA = 25˚C
TA = 45˚C
TA = 70˚C
1.2
1.18
TA = 85˚C
FRC(MHz)
1.16
1.14
1.12
1.1
1.08
1.06
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC(V)
Figure 65. Watchdog Oscillator Frequency vs. VCC
WATCHDOG OSCILLATOR FREQUENCY vs. Vcc
1600
1400
TA = 25˚C
1200
TA = 85˚C
FRC (kHz)
1000
800
600
400
200
0
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
VCC (V)
76
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Sink and source capabilities of I/O ports are measured on one pin at a time.
Figure 66. 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
VOP (V)
3
3.5
4
4.5
5
Figure 67. Pull-up Resistor Current vs. Input Voltage (VCC = 2.7V)
30
TA = 25˚C
25
TA = 85˚C
IOP (µA)
20
15
10
5
0
0
0.5
1
1.5
2
2.5
3
VOP (V)
77
1006D–AVR–07/03
Figure 68. I/O Pin Sink Current vs. Output Voltage (VCC = 5V)
70
TA = 25˚C
60
TA = 85˚C
50
I OL (mA)
40
30
20
10
0
0
0.5
1
1.5
2
2.5
3
VOL (V)
Figure 69. 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)
78
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Figure 70. I/O Pin Sink Current vs. Output Voltage (VCC = 2.7V)
25
TA = 25˚C
20
TA = 85˚C
I OL (mA)
15
10
5
0
0
0.5
1
1.5
2
VOL (V)
Figure 71. I/O Pin Source Current vs. Output Voltage (VCC = 2.7V)
6
TA = 25˚C
5
TA = 85˚C
I OH (mA)
4
3
2
1
0
0
0.5
1
1.5
2
2.5
3
VOH (V)
79
1006D–AVR–07/03
Figure 72. 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 73. I/O Pin Input Hysteresis vs. VCC (TA = 25°C)
0.18
Input Hysteresis (V)
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
2.7
4.0
5.0
VCC
80
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Register Summary ATtiny11
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
$3F
SREG
I
T
H
S
V
N
Z
C
page 14
$3E
Reserved
$3D
Reserved
$3C
Reserved
$3B
GIMSK
-
INT0
PCIE
-
-
-
-
-
page 25
$3A
GIFR
-
INTF0
PCIF
-
-
-
-
-
page 26
$39
TIMSK
-
-
-
-
-
-
TOIE0
-
page 26
$38
TIFR
-
-
-
-
-
-
TOV0
-
page 27
$37
Reserved
$36
Reserved
$35
MCUCR
-
-
SE
SM
-
-
ISC01
ISC00
page 29
$34
MCUSR
-
-
-
-
-
-
EXTRF
PORF
page 23
$33
TCCR0
-
-
-
-
-
CS02
CS01
CS00
page 34
$32
TCNT0
$31
Reserved
$30
Reserved
...
Reserved
$22
Reserved
$21
WDTCR
$20
Reserved
$1F
Reserved
$1E
Reserved
$1D
Reserved
$1C
Reserved
$1B
Reserved
page 35
-
-
-
WDTOE
WDE
WDP2
WDP1
WDP0
page 36
$1A
Reserved
$19
Reserved
$18
PORTB
-
-
-
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
page 44
$17
DDRB
-
-
-
DDB4
DDB3
DDB2
DDB1
DDB0
page 44
-
-
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
page 44
ACD
-
ACO
ACI
ACIE
-
ACIS1
ACIS0
page 41
$16
PINB
$15
Reserved
...
Reserved
$0A
Reserved
$09
Reserved
$08
ACSR
…
Reserved
$00
Notes:
Timer/Counter0 (8 Bit)
Reserved
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 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.
81
1006D–AVR–07/03
Register Summary ATtiny12
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Page
$3F
SREG
I
T
H
S
V
N
Z
C
page 14
$3E
Reserved
$3D
Reserved
$3C
Reserved
$3B
GIMSK
-
INT0
PCIE
-
-
-
-
-
page 25
$3A
GIFR
-
INTF0
PCIF
-
-
-
-
-
page 26
$39
TIMSK
-
-
-
-
-
-
TOIE0
-
page 26
$38
TIFR
-
-
-
-
-
-
TOV0
-
page 27
$37
Reserved
$36
Reserved
$35
MCUCR
-
PUD
SE
SM
-
-
ISC01
ISC00
page 29
$34
MCUSR
-
-
-
-
WDRF
BORF
EXTRF
PORF
page 24
$33
TCCR0
-
-
-
-
-
CS02
CS01
CS00
page 34
$32
TCNT0
$31
OSCCAL
$30
Reserved
...
Reserved
$22
Reserved
$21
WDTCR
$20
Reserved
$1F
Reserved
$1E
EEAR
$1D
EEDR
$1C
EECR
$1B
Reserved
page 35
page 32
-
-
-
-
-
WDTOE
WDE
WDP2
WDP1
WDP0
EEPROM Address Register
page 38
EEPROM Data Register
-
-
page 36
page 38
-
-
EERIE
EEMWE
EEWE
EERE
page 38
$1A
Reserved
$19
Reserved
$18
PORTB
-
-
-
PORTB4
PORTB3
PORTB2
PORTB1
PORTB0
page 44
$17
DDRB
-
-
DDB5
DDB4
DDB3
DDB2
DDB1
DDB0
page 44
$16
PINB
-
-
PINB5
PINB4
PINB3
PINB2
PINB1
PINB0
page 44
$15
Reserved
ACD
AINBG
ACO
ACI
ACIE
-
ACIS1
ACIS0
page 41
...
Reserved
$0A
Reserved
$09
Reserved
$08
ACSR
...
Reserved
$00
Note:
Timer/Counter0 (8 Bit)
Oscillator Calibration Register
Reserved
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 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.
82
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Instruction Set Summary
Mnemonics
Operands
Description
Operation
Flags
#Clocks
ARITHMETIC AND LOGIC INSTRUCTIONS
ADD
Rd, Rr
Add two Registers
Rd ← Rd + Rr
Z,C,N,V,H
1
ADC
Rd, Rr
Add with Carry two Registers
Rd ← Rd + Rr + C
Z,C,N,V,H
1
SUB
Rd, Rr
Subtract two Registers
Rd ← Rd - Rr
Z,C,N,V,H
1
SUBI
Rd, K
Subtract Constant from Register
Rd ← Rd - K
Z,C,N,V,H
1
SBC
Rd, Rr
Subtract with Carry two Registers
Rd ← Rd - Rr - C
Z,C,N,V,H
1
SBCI
Rd, K
Subtract with Carry Constant from Reg.
Rd ← Rd - K - C
Z,C,N,V,H
1
AND
Rd, Rr
Logical AND Registers
Rd ← Rd • Rr
Z,N,V
1
ANDI
Rd, K
Logical AND Register and Constant
Rd ← Rd • K
Z,N,V
1
OR
Rd, Rr
Logical OR Registers
Rd ← Rd v Rr
Z,N,V
1
ORI
Rd, K
Logical OR Register and Constant
Rd ← Rd v K
Z,N,V
1
EOR
Rd, Rr
Exclusive OR Registers
Rd ← Rd⊕Rr
Z,N,V
1
COM
Rd
One’s Complement
Rd ← $FF - Rd
Z,C,N,V
1
NEG
Rd
Two’s Complement
Rd ← $00 - Rd
Z,C,N,V,H
1
SBR
Rd,K
Set Bit(s) in Register
Rd ← Rd v K
Z,N,V
1
CBR
Rd,K
Clear Bit(s) in Register
Rd ← Rd • (FFh - K)
Z,N,V
1
INC
Rd
Increment
Rd ← Rd + 1
Z,N,V
1
DEC
Rd
Decrement
Rd ← Rd - 1
Z,N,V
1
TST
Rd
Test for Zero or Minus
Rd ← Rd • Rd
Z,N,V
1
CLR
Rd
Clear Register
Rd ← Rd⊕Rd
Z,N,V
1
SER
Rd
Set Register
Rd ← $FF
None
1
BRANCH INSTRUCTIONS
RJMP
k
Relative Jump
PC ← PC + k + 1
None
2
RCALL
k
Relative Subroutine Call
PC ← PC + k + 1
None
3
RET
Subroutine Return
PC ← STACK
None
4
RETI
Interrupt Return
PC ← STACK
I
4
CPSE
Rd,Rr
Compare, Skip if Equal
if (Rd = Rr) PC ← PC + 2 or 3
None
CP
Rd,Rr
Compare
Rd - Rr
Z, N,V,C,H
CPC
Rd,Rr
Compare with Carry
Rd - Rr - C
Z, N,V,C,H
1
CPI
Rd,K
Compare Register with Immediate
Rd - K
Z, N,V,C,H
1
1/2
1
SBRC
Rr, b
Skip if Bit in Register Cleared
if (Rr(b)=0) PC ← PC + 2 or 3
None
SBRS
Rr, b
Skip if Bit in Register is Set
if (Rr(b)=1) PC ← PC + 2 or 3
None
1/2
SBIC
P, b
Skip if Bit in I/O Register Cleared
if (P(b)=0) PC ← PC + 2 or 3
None
1/2
SBIS
P, b
Skip if Bit in I/O Register is Set
if (P(b)=1) PC ← PC + 2 or 3
None
1/2
BRBS
s, k
Branch if Status Flag Set
if (SREG(s) = 1) then PC←PC + k + 1
None
1/2
BRBC
s, k
Branch if Status Flag Cleared
if (SREG(s) = 0) then PC←PC + k + 1
None
1/2
BREQ
k
Branch if Equal
if (Z = 1) then PC ← PC + k + 1
None
1/2
BRNE
k
Branch if Not Equal
if (Z = 0) then PC ← PC + k + 1
None
1/2
BRCS
k
Branch if Carry Set
if (C = 1) then PC ← PC + k + 1
None
1/2
BRCC
k
Branch if Carry Cleared
if (C = 0) then PC ← PC + k + 1
None
1/2
BRSH
k
Branch if Same or Higher
if (C = 0) then PC ← PC + k + 1
None
1/2
BRLO
k
Branch if Lower
if (C = 1) then PC ← PC + k + 1
None
1/2
BRMI
k
Branch if Minus
if (N = 1) then PC ← PC + k + 1
None
1/2
BRPL
k
Branch if Plus
if (N = 0) then PC ← PC + k + 1
None
1/2
BRGE
k
Branch if Greater or Equal, Signed
if (N ⊕ V= 0) then PC ← PC + k + 1
None
1/2
BRLT
k
Branch if Less Than Zero, Signed
if (N ⊕ V= 1) then PC ← PC + k + 1
None
1/2
BRHS
k
Branch if Half Carry Flag Set
if (H = 1) then PC ← PC + k + 1
None
1/2
BRHC
k
Branch if Half Carry Flag Cleared
if (H = 0) then PC ← PC + k + 1
None
1/2
BRTS
k
Branch if T Flag Set
if (T = 1) then PC ← PC + k + 1
None
1/2
1/2
BRTC
k
Branch if T Flag Cleared
if (T = 0) then PC ← PC + k + 1
None
1/2
BRVS
k
Branch if Overflow Flag is Set
if (V = 1) then PC ← PC + k + 1
None
1/2
BRVC
k
Branch if Overflow Flag is Cleared
if (V = 0) then PC ← PC + k + 1
None
1/2
BRIE
k
Branch if Interrupt Enabled
if ( I = 1) then PC ← PC + k + 1
None
1/2
BRID
k
Branch if Interrupt Disabled
if ( I = 0) then PC ← PC + k + 1
None
1/2
83
1006D–AVR–07/03
Instruction Set Summary (Continued)
Mnemonics
Operands
Description
Operation
Flags
#Clocks
DATA TRANSFER INSTRUCTIONS
LD
Rd,Z
Load Register Indirect
Rd ← (Z)
None
2
ST
Z,Rr
Store Register Indirect
(Z) ← Rr
None
2
MOV
Rd, Rr
Move Between Registers
Rd ← Rr
None
1
LDI
Rd, K
Load Immediate
Rd ← K
None
1
IN
Rd, P
In Port
Rd ← P
None
1
OUT
P, Rr
Out Port
P ← Rr
None
1
Load Program Memory
R0 ← (Z)
None
3
2
LPM
BIT AND BIT-TEST INSTRUCTIONS
SBI
P,b
Set Bit in I/O Register
I/O(P,b) ← 1
None
CBI
P,b
Clear Bit in I/O Register
I/O(P,b) ← 0
None
2
LSL
Rd
Logical Shift Left
Rd(n+1) ← Rd(n), Rd(0) ← 0
Z,C,N,V
1
LSR
Rd
Logical Shift Right
Rd(n) ← Rd(n+1), Rd(7) ← 0
Z,C,N,V
1
ROL
Rd
Rotate Left Through Carry
Rd(0) ← C, Rd(n+1) ← Rd(n), C ← Rd(7)
Z,C,N,V
1
ROR
Rd
Rotate Right Through Carry
Rd(7) ← C, Rd(n) ← Rd(n+1), C ← Rd(0)
Z,C,N,V
1
ASR
Rd
Arithmetic Shift Right
Rd(n) ← Rd(n+1), n = 0..6
Z,C,N,V
1
SWAP
Rd
Swap Nibbles
Rd(3..0) ← Rd(7..4), Rd(7..4) ← Rd(3..0)
None
1
BSET
s
Flag Set
SREG(s) ← 1
SREG(s)
1
BCLR
s
Flag Clear
SREG(s) ← 0
SREG(s)
1
BST
Rr, b
Bit Store from Register to T
T ← Rr(b)
T
1
BLD
Rd, b
Bit load from T to Register
Rd(b) ← T
None
1
Set Carry
C←1
C
1
SEC
CLC
Clear Carry
C←0
C
1
SEN
Set Negative Flag
N←1
N
1
CLN
Clear Negative Flag
N←0
N
1
SEZ
Set Zero Flag
Z←1
Z
1
CLZ
Clear Zero Flag
Z←0
Z
1
SEI
Global Interrupt Enable
I←1
I
1
CLI
Global Interrupt Disable
I←0
I
1
SES
Set Signed Test Flag
S←1
S
1
CLS
Clear Signed Test Flag
S←0
S
1
SEV
Set Twos Complement Overflow
V←1
V
1
CLV
Clear Twos Complement Overflow
V←0
V
1
SET
Set T in SREG
T←1
T
1
CLT
Clear T in SREG
T←0
T
1
SEH
Set Half Carry Flag in SREG
H←1
H
1
CLH
Clear Half Carry Flag in SREG
H←0
H
1
NOP
No Operation
None
1
SLEEP
Sleep
(see specific descr. for Sleep function)
None
1
WDR
Watch Dog Reset
(see specific descr. for WDR/timer)
None
1
84
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Ordering Information
Power Supply
Speed (MHz)
Ordering Code
Package
2.7 - 5.5V
2
ATtiny11L-2PC
ATtiny11L-2SC
8P3
8S2
Commercial
(0°C to 70°C)
ATtiny11L-2PI
ATtiny11L-2SI
8P3
8S2
Industrial
(-40°C to 85°C)
ATtiny11-6PC
ATtiny11-6SC
8P3
8S2
Commercial
(0°C to 70°C)
ATtiny11-6PI
ATtiny11-6SI
8P3
8S2
Industrial
(-40°C to 85°C)
ATtiny12V-1PC
ATtiny12V-1SC
8P3
8S2
Commercial
(0°C to 70°C)
ATtiny12V-1PI
ATtiny12V-1SI
8P3
8S2
Industrial
(-40°C to 85°C)
ATtiny12L-4PC
ATtiny12L-4SC
8P3
8S2
Commercial
(0°C to 70°C)
ATtiny12L-4PI
ATtiny12L-4SI
8P3
8S2
Industrial
(-40°C to 85°C)
ATtiny12-8PC
ATtiny12-8SC
8P3
8S2
Commercial
(0°C to 70°C)
ATtiny12-8PI
ATtiny12-8SI
8P3
8S2
Industrial
(-40°C to 85°C)
4.0 - 5.5V
1.8 - 5.5V
2.7 - 5.5V
4.0 - 5.5V
Note:
6
1.2
4
8
Operation Range
The speed grade refers to maximum clock rate when using an external crystal or external clock drive. The internal RC oscillator
has the same nominal clock frequency for all speed grades.
Package Type
8P3
8-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
8S2
8-lead, 0.200" Wide, Plastic Gull-Wing Small Outline (EIAJ SOIC)
85
1006D–AVR–07/03
Packaging Information
8P3
E
1
E1
N
Top View
c
eA
End View
COMMON DIMENSIONS
(Unit of Measure = inches)
D
e
D1
A2 A
SYMBOL
MIN
NOM
A
b2
b3
b
4 PLCS
Side View
L
0.210
NOTE
2
A2
0.115
0.130
0.195
b
0.014
0.018
0.022
5
b2
0.045
0.060
0.070
6
6
b3
0.030
0.039
0.045
c
0.008
0.010
0.014
D
0.355
0.365
0.400
D1
0.005
E
0.300
0.310
0.325
4
E1
0.240
0.250
0.280
3
e
3
3
0.100 BSC
eA
L
Notes:
MAX
0.300 BSC
0.115
0.130
4
0.150
2
1. This drawing is for general information only; refer to JEDEC Drawing MS-001, Variation BA for additional information.
2. Dimensions A and L are measured with the package seated in JEDEC seating plane Gauge GS-3.
3. D, D1 and E1 dimensions do not include mold Flash or protrusions. Mold Flash or protrusions shall not exceed 0.010 inch.
4. E and eA measured with the leads constrained to be perpendicular to datum.
5. Pointed or rounded lead tips are preferred to ease insertion.
6. b2 and b3 maximum dimensions do not include Dambar protrusions. Dambar protrusions shall not exceed 0.010 (0.25 mm).
01/09/02
R
86
2325 Orchard Parkway
San Jose, CA 95131
TITLE
8P3, 8-lead, 0.300" Wide Body, Plastic Dual
In-line Package (PDIP)
DRAWING NO.
REV.
8P3
B
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
8S2
1
H
N
Top View
e
b
A
D
COMMON DIMENSIONS
(Unit of Measure = mm)
Side View
SYMBOL
A
C
A1
L
E
End View
NOM
MAX
NOTE
2.03
A1
0.05
0.33
b
0.35
0.51
5
C
0.18
0.25
5
D
5.13
5.38
E
5.13
5.41
H
7.62
8.38
L
0.51
0.89
e
Notes: 1.
2.
3.
4.
5.
MIN
1.78
1.27 BSC
2, 3
4
This drawing is for general information only; refer to EIAJ Drawing EDR-7320 for additional information.
Mismatch of the upper and lower dies and resin burrs aren't included.
It is recommended that upper and lower cavities be equal. If they are different, the larger dimension shall be regarded.
Determines the true geometric position.
Values b,C apply to pb/Sn solder plated terminal. The standard thickness of the solder layer shall be 0.010 +0.010/-0.005 mm.
5/2/02
R
2325 Orchard Parkway
San Jose, CA 95131
TITLE
8S2, 8-lead, 0.209" Body, Plastic Small
Outline Package (EIAJ)
DRAWING NO.
8S2
REV.
B
87
1006D–AVR–07/03
Data Sheet Change
Log for ATtiny11/12
Please note that the referring page numbers in this section are referred to this document. The referring revision in this section are referring to the document revision.
Changes from Rev.
1006C-09/01 to Rev.
1006D-07/03
1. Updated VBOT values in Table 8 on page 19.
88
ATtiny11/12
1006D–AVR–07/03
ATtiny11/12
Table of Contents
Features................................................................................................. 1
Pin Configuration.................................................................................. 1
Description ............................................................................................ 2
ATtiny11 Block Diagram .......................................................................................
ATtiny12 Block Diagram .......................................................................................
Pin Descriptions....................................................................................................
Clock Options .......................................................................................................
2
4
5
5
Architectural Overview......................................................................... 8
General-purpose Register File.............................................................................. 9
ALU – Arithmetic Logic Unit................................................................................ 10
Flash Program Memory ...................................................................................... 10
Program and Data Addressing Modes................................................................ 10
Subroutine and Interrupt Hardware Stack .......................................................... 12
EEPROM Data Memory...................................................................................... 13
Memory Access and Instruction Execution Timing ............................................. 13
I/O Memory ......................................................................................................... 14
Reset and Interrupt Handling.............................................................................. 15
ATtiny12 Internal Voltage Reference.................................................................. 24
Interrupt Handling ............................................................................................... 25
Sleep Modes for the ATtiny11 ............................................................................ 31
Sleep Modes for the ATtiny12 ............................................................................ 31
ATtiny12 Calibrated Internal RC Oscillator ......................................................... 32
Timer/Counter0 ................................................................................... 33
Timer/Counter Prescaler..................................................................................... 33
Watchdog Timer.................................................................................. 36
ATtiny12 EEPROM Read/Write Access............................................. 38
Prevent EEPROM Corruption ............................................................................. 40
Analog Comparator ............................................................................ 41
I/O Port B ............................................................................................. 43
Memory Programming........................................................................ 46
Program (and Data) Memory Lock Bits ..............................................................
Fuse Bits in ATtiny11..........................................................................................
Fuse Bits in ATtiny12..........................................................................................
Signature Bytes ..................................................................................................
Calibration Byte in ATtiny12 ...............................................................................
Programming the Flash and EEPROM...............................................................
High-voltage Serial Programming.......................................................................
46
46
46
47
47
47
48
i
1006D–AVR–07/03
High-voltage Serial Programming Algorithm.......................................................
High-voltage Serial Programming Characteristics ..............................................
Low-voltage Serial Downloading (ATtiny12 only) ...............................................
Low-voltage Serial Programming Characteristics ...............................................
49
52
52
56
Electrical Characteristics................................................................... 57
Absolute Maximum Ratings ................................................................................
DC Characteristics – Preliminary Data ...............................................................
External Clock Drive Waveforms ........................................................................
External Clock Drive ATtiny11 ............................................................................
External Clock Drive ATtiny12 ............................................................................
ATtiny11 Typical Characteristics ........................................................................
ATtiny12 Typical Characteristics ........................................................................
57
57
59
59
59
60
72
Register Summary ATtiny11 .............................................................. 81
Register Summary ATtiny12 .............................................................. 82
Instruction Set Summary ................................................................... 83
Ordering Information .......................................................................... 85
Packaging Information ....................................................................... 86
8P3 ..................................................................................................................... 86
8S2 ..................................................................................................................... 87
Data Sheet Change Log for Chip Number ........................................ 88
Changes from Rev. 1006C-09/01 to Rev. 1006D-07/03..................................... 88
Table of Contents .................................................................................. i
ii
ATtiny11/12
1006D–AVR–07/03
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1006D–AVR–07/03
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