Features
•High Performance, Low Power AVR® 8-Bit Microcontroller
•Advanced RISC Architecture
– 123 Powerful Instructions – Most Single Clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
•Non-volatile Program and Data Memories
– 2/4/8K Byte of In-System Programmable Program Memory Flash
• Endurance: 10,000 Write/Erase Cycles
– 128/256/512 Bytes In-System Programmable EEPROM
• Endurance: 100,000 Write/Erase Cycles
– 128/256/512 Bytes Internal SRAM
– Data retention: 20 years at 85°C / 100 years at 25°C
– Programming Lock for Self-Programming Flash Program & EEPROM Data Security
•Peripheral Features
– 8/16-bit Timer/Counter with Prescaler
– 8/10-bit High Speed Timer/Counter with Separate Prescaler
• 3 High Frequency PWM Outputs with Separate Output Compare Registers
• Programmable Dead Time Generator
– 10-bit ADC
• 11 Single-Ended Channels
• 16 Differential ADC Channel Pairs
• 15 Differential ADC Channel Pairs with Programmable Gain (1x, 8x, 20x, 32x)
– On-chip Analog Comparator
– Programmable Watchdog Timer with Separate On-chip Oscillator
– Universal Serial Interface with Start Condition Detector
•Special Microcontroller Features
– debugWIRE On-chip Debug System
– In-System Programmable via SPI Port
– External and Internal Interrupt Sources
– Low Power Idle, ADC Noise Reduction, Standby and Power-Down Modes
– Enhanced Power-on Reset Circuit
– Programmable Brown-out Detection Circuit
– Internal Calibrated Oscillator
– On-chip Temperature Sensor
•I/O and Packages
– 16 Programmable I/O Lines
– Available in 20-pin PDIP, 20-pin SOIC and 32-pad MLF
•Operating Voltage:
– 1.8 – 5.5V for ATtiny261V/461V/861V
– 2.7 – 5.5V for ATtiny261/461/861
•Speed Grade:
– ATtiny261V/461V/861V: 0 – 4 MHz @ 1.8 – 5.5V, 0 – 10 MHz @ 2.7 – 5.5V
– ATtiny261/461/861: 0 – 10 MHz @ 2.7 – 5.5V, 0 – 20 MHz @ 4.5 – 5.5V
•Industrial Temperature Range
•Low Power Consumption
– Active Mode (1 MHz System Clock): 300 µA @ 1.8V
– Power-Down Mode: 0.1 µA at 1.8V
8-bit
Microcontroller
with 2/4/8K
Bytes In-System
Programmable
Flash
ATtiny261/V
ATtiny461/V
ATtiny861/V
Summary
2588ES–AVR–08/10
2
2588ES–AVR–08/10
ATtiny261/461/861
1. Pin Configurations
Figure 1-1. Pinout ATtiny261/461/861 and ATtiny261V/461V/861V
Note: To ensure mechanical stability the center pad underneath the QFN/MLF package should be soldered to ground on the board.
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
(MOSI/DI/SDA/OC1A/PCINT8) PB0
(MISO/DO/OC1A/PCINT9) PB1
(SCK/USCK/SCL/OC1B/PCINT10) PB2
(OC1B/PCINT11) PB3
VCC
GND
(ADC7/OC1D/CLKI/XTAL1/PCINT12) PB4
(ADC8/OC1D/CLKO/XTAL2/PCINT13) PB5
(ADC9/INT0/T0/PCINT14) PB6
(ADC10/RESET/PCINT15) PB7
PA0 (ADC0/DI/SDA/PCINT0)
PA1 (ADC1/DO/PCINT1)
PA2 (ADC2/INT1/USCK/SCL/PCINT2)
PA3 (AREF/PCINT3)
AGND
AVCC
PA4 (ADC3/ICP0/PCINT4)
PA5 (ADC4/AIN2/PCINT5)
PA6 (ADC5/AIN0/PCINT6)
PA7 (ADC6/AIN1/PCINT7)
PDIP/SOIC
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
32
31
30
29
28
27
26
25
9
10
11
12
13
14
15
16
NC
(OC1B/PCINT11) PB3
NC
VCC
GND
NC
(ADC7/OC1D/CLKI/XTAL1/PCINT12) PB4
(ADC8/OC1D/CLKO/XTAL2/PCINT13) PB5
NC
PA2 (ADC2/INT1/USCK/SCL/PCINT2)
PA3 (AREF/PCINT3)
AGND
NC
NC
AVCC
PA4 (ADC3/ICP0/PCINT4)
NC
(ADC9/INT0/T0/PCINT14) PB6
(ADC10/RESET/PCINT15) PB7
NC
(ADC6/AIN1/PCINT7) PA7
(ADC5/AIN0/PCINT6) PA6
(ADC4/AIN2/PCINT5) PA5
NC
PB2 (SCK/USCK/SCL/OC1B/PCINT10)
PB1 (MISO/DO/OC1A/PCINT9)
PB0 (MOSI/DI/SDA/OC1A/PCINT8)
NC
NC
NC
PA0 (ADC0/DI/SDA/PCINT0)
PA1 (ADC1/DO/PCINT1)
QFN/MLF
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2588ES–AVR–08/10
ATtiny261/461/861
1.1 Pin Descriptions
1.1.1 VCC
Supply voltage.
1.1.2 GND
Ground.
1.1.3 AVCC
Analog supply voltage. This is the supply voltage pin for the Analog-to-digital Converter (ADC),
the analog comparator, the Brown-Out Detector (BOD), the internal voltage reference and Port
A. It should be externally connected to VCC, even if some peripherals such as the ADC are not
used. If the ADC is used AVCC should be connected to VCC through a low-pass filter.
1.1.4 AGND
Analog ground.
1.1.5 Port A (PA7:PA0)
An 8-bit, bi-directional I/O port with internal pull-up resistors, individually selectable for each bit.
Output buffers have symmetrical drive characteristics with both high sink and source capability.
As inputs, port pins that are externally pulled low will source current if pull-up resistors have
been activated. Port pins are tri-stated when a reset condition becomes active, even if the clock
is not running.
Port A also serves the functions of various special features of the device, as listed on page 63.
1.1.6 Port B (PB7:PB0)
An 8-bit, bi-directional I/O port with internal pull-up resistors, individually selectable for each bit.
Output buffers have symmetrical drive characteristics with both high sink and source capability.
As inputs, port pins that are externally pulled low will source current if pull-up resistors have
been activated. Port pins are tri-stated when a reset condition becomes active, even if the clock
is not running.
Port B also serves the functions of various special features of the device, as listed on page 66.
1.1.7 RESET
Reset input. A low level on this pin for longer than the minimum pulse length will generate a
reset, even if the clock is not running and provided the reset pin has not been disabled. The min-
imum pulse length is given in Table 19-4 on page 190. Shorter pulses are not guaranteed to
generate a reset.
The reset pin can also be used as a (weak) I/O pin.
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2588ES–AVR–08/10
ATtiny261/461/861
2. Overview
ATtiny261/461/861 are low-power CMOS 8-bit microcontrollers based on the AVR enhanced
RISC architecture. By executing powerful instructions in a single clock cycle, the
ATtiny261/461/861 achieves throughputs approaching 1 MIPS per MHz allowing the system
designer to optimize power consumption versus processing speed.
2.1 Block Diagram
Figure 2-1. Block Diagram
The AVR core combines a rich instruction set with 32 general purpose working registers. All 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 con-
ventional CISC microcontrollers.
PORT A (8)PORT B (8)
USI
Timer/Counter1
Timer/Counter0 A/D Conv.
Internal
Bandgap
Analog Comp.
SRAMFlash
EEPROM
Watchdog
Oscillator
Watchdog
Timer
Oscillator
Circuits /
Clock
Generation
Power
Supervision
POR / BOD &
RESET
VCC
GND
PROGRAM
LOGIC
debugWIRE
AGND
AREF
AVCC
D ATA BU S
PA[0..7]PB[0..7]
11
RESET
XTAL[1..2]
CPU
3
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2588ES–AVR–08/10
ATtiny261/461/861
The ATtiny261/461/861 provides the following features: 2/4/8K byte of In-System Programmable
Flash, 128/256/512 bytes EEPROM, 128/256/512 bytes SRAM, 16 general purpose I/O lines, 32
general purpose working registers, an 8-bit Timer/Counter with compare modes, an 8-bit high
speed Timer/Counter, a Universal Serial Interface, Internal and External Interrupts, an 11-chan-
nel, 10-bit ADC, a programmable Watchdog Timer with internal oscillator, and four software
selectable power saving modes. Idle mode stops the CPU while allowing the SRAM,
Timer/Counter, ADC, Analog Comparator, and Interrupt system to continue functioning. Power-
down mode saves the register contents, disabling all chip functions until the next Interrupt or
Hardware Reset. ADC Noise Reduction mode stops the CPU and all I/O modules except ADC,
to minimize switching noise during ADC conversions. In Standby mode, the crystal/resonator
oscillator is running while the rest of the device is sleeping, allowing very fast start-up combined
with low power consumption.
The device is manufactured using Atmel’s high density non-volatile memory technology. The
On-chip ISP Flash allows the Program memory to be re-programmed In-System through an SPI
serial interface, by a conventional non-volatile memory programmer or by an On-chip boot code
running on the AVR core.
The ATtiny261/461/861 AVR is supported by a full suite of program and system development
tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators, and Evaluation
kits.
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2588ES–AVR–08/10
ATtiny261/461/861
3. About
3.1 Resources
A comprehensive set of drivers, application notes, data sheets and descriptions on development
tools are available for download at http://www.atmel.com/avr.
3.2 Code Examples
This documentation contains simple code examples that briefly show how to use various parts of
the device. These code examples assume that the part specific header file is included before
compilation. Be aware that not all C compiler vendors include bit definitions in the header files
and interrupt handling in C is compiler dependent. Please confirm with the C compiler documen-
tation for more details.
For I/O Registers located in the extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”, and “SBI”
instructions must be replaced with instructions that allow access to extended I/O. Typically, this
means “LDS” and “STS” combined with “SBRS”, “SBRC”, “SBR”, and “CBR”. Note that not all
AVR devices include an extended I/O map.
3.3 Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less
than 1 PPM over 20 years at 85°C or 100 years at 25°C.
3.4 Disclaimer
Typical values contained in this data sheet are based on simulations and characterization of
other AVR microcontrollers manufactured on the same process technology.
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2588ES–AVR–08/10
ATtiny261/461/861
4. Register Summary
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Page
0x3F (0x5F) SREG I T H S V N Z C page 8
0x3E (0x5E) SPH – – – – – SP10 SP9 SP8 page 11
0x3D (0x5D) SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 page 11
0x3C (0x5C) Reserved –
0x3B (0x5B) GIMSK INT1 INT0 PCIE1 PCIE0 – – – – page 52
0x3A (0x5A) GIFR INTF1 INTF0 PCIF – – – – – page 53
0x39 (0x59) TIMSK OCIE1D OCIE1A OCIE1B OCIE0A OCIE0B TOIE1 TOIE0 TICIE0 page 86, page 123
0x38 (0x58) TIFR OCF1D OCF1A OCF1B OCF0A OCF0B TOV1 TOV0 ICF0 page 87, page 123
0x37 (0x57) SPMCSR – – – CTPB RFLB PGWRT PGERS SPMEN page 169
0x36 (0x56) PRR PRTIM1 PRTIM0 PRUSI PRADC page 37
0x35 (0x55) MCUCR –PUDSESM1SM0 –ISC01ISC00page 39, page 69, page 52
0x34 (0x54) MCUSR – – – – WDRF BORF EXTRF PORF page 47,
0x33 (0x53) TCCR0B – – – TSM PSR0 CS02 CS01 CS00 page 85
0x32 (0x52) TCNT0L Timer/Counter0 Counter Register Low Byte page 85
0x31 (0x51) OSCCAL Oscillator Calibration Register page 32
0x30 (0x50) TCCR1A COM1A1 COM1A0 COM1B1 COM1B0 FOC1A FOC1B PWM1A PWM1B page 112
0x2F (0x4F) TCCR1B PWM1X PSR1 DTPS11 DTPS10 CS13 CS12 CS11 CS10 page 169
0x2E (0x4E) TCNT1 Timer/Counter1 Counter Register page 121
0x2D (0x4D) OCR1A Timer/Counter1 Output Compare Register A page 121
0x2C (0x4C) OCR1B Timer/Counter1 Output Compare Register B page 122
0x2B (0x4B) OCR1C Timer/Counter1 Output Compare Register C page 122
0x2A (0x4A) OCR1D Timer/Counter1 Output Compare Register D page 122
0x29 (0x49) PLLCSR LSM PCKE PLLE PLOCK page 120
0x28 (0x48) CLKPR CLKPCE CLKPS3 CLKPS2 CLKPS1 CLKPS0 page 32
0x27 (0x47) TCCR1C COM1A1S COM1A0S COM1B1S COM1B0S COM1D1 COM1D0 FOC1D PWM1D page 117
0x26 (0x46) TCCR1D FPIE1 FPEN1 FPNC1 FPES1 FPAC1 FPF1 WGM11 WGM10 page 118
0x25 (0x45) TC1H TC19 TC18 page 121
0x24 (0x44) DT1 DT1H3 DT1H2 DT1H1 DT1H0 DT1L3 DT1L2 DT1L1 DT1L0 page 124
0x23 (0x43) PCMSK0 PCINT7 PCINT6 PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 page 54
0x22 (0x42) PCMSK1 PCINT15 PCINT14 PCINT13 PCINT12 PCINT11 PCINT10 PCINT9 PCINT8 page 54
0x21 (0x41) WDTCR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0 page 47
0x20 (0x40) DWDR DWDR[7:0] page 37
0x1F (0x3F) EEARH EEAR8 page 20
0x1E (0x3E) EEARL EEAR7 EEAR6 EEAR5 EEAR4 EEAR3 EEAR2 EEAR1 EEAR0 page 21
0x1D (0x3D) EEDR EEPROM Data Register page 21
0x1C (0x3C) EECR –– EEPM1 EEPM0 EERIE EEMPE EEPE EERE page 21
0x1B (0x3B) PORTA PORTA7 PORTA6 PORTA5 PORTA4 PORTA3 PORTA2 PORTA1 PORTA0 page 69
0x1A (0x3A) DDRA DDA7 DDA6 DDA5 DDA4 DDA3 DDA2 DDA1 DDA0 page 69
0x19 (0x39) PINA PINA7 PINA6 PINA5 PINA4 PINA3 PINA2 PINA1 PINA0 page 70
0x18 (0x38) PORTB PORTB7 PORTB6 PORTB5 PORTB4 PORTB3 PORTB2 PORTB1 PORTB0 page 70
0x17 (0x37) DDRB DDB7 DDB6 DDB5 DDB4 DDB3 DDB2 DDB1 DDB0 page 70
0x16 (0x36) PINB PINB7 PINB6 PINB5 PINB4 PINB3 PINB2 PINB1 PINB0 page 70
0x15 (0x35) TCCR0A TCW0 ICEN0 ICNC0 ICES0 ACIC0 CTC0 page 84
0x14 (0x34) TCNT0H Timer/Counter0 Counter Register High Byte page 86
0x13 (0x33) OCR0A Timer/Counter0 Output Compare Register A page 86
0x12 (0x32) OCR0B Timer/Counter0 Output Compare Register B page 86
0x11 (0x31) USIPP USIPOS page 136
0x10 (0x30) USIBR USI Buffer Register page 133
0x0F (0x2F) USIDR USI Data Register page 132
0x0E (0x2E) USISR USISIF USIOIF USIPF USIDC USICNT3 USICNT2 USICNT1 USICNT0 page 133
0x0D (0x2D) USICR USISIE USIOIE USIWM1 USIWM0 USICS1 USICS0 USICLK USITC page 134
0x0C (0x2C) GPIOR2 General Purpose I/O Register 2 page 22
0x0B (0x2B) GPIOR1 General Purpose I/O Register 1 page 23
0x0A (0x2A) GPIOR0 General Purpose I/O Register 0 page 23
0x09 (0x29) ACSRB HSEL HLEV ACM2 ACM1 ACM0 page 140
0x08 (0x28) ACSRA ACD ACBG ACO ACI ACIE ACME ACIS1 ACIS0 page 139
0x07 (0x27) ADMUX REFS1 REFS0 ADLAR MUX4 MUX3 MUX2 MUX1 MUX0 page 155
0x06 (0x26) ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 page 159
0x05 (0x25) ADCH ADC Data Register High Byte page 160
0x04 (0x24) ADCL ADC Data Register Low Byte page 160
0x03 (0x23) ADCSRB BIN GSEL REFS2MUX5ADTS2ADTS1ADTS0 page 161
0x02 (0x22) DIDR1 ADC10D ADC9D ADC8D ADC7D page 162
0x01 (0x21) DIDR0 ADC6D ADC5D ADC4D ADC3D AREFD ADC2D ADC1D ADC0D page 162
0x00 (0x20) TCCR1E –- OC1OE5 OC1OE4 OC1OE3 OC1OE2 OC1OE1 OC1OE0 page 119
8
2588ES–AVR–08/10
ATtiny261/461/861
Note: 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. I/O Registers within the address range 0x00 - 0x1F 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.
3. Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most other AVRs, the CBI and SBI
instructions will only operation the specified bit, and can therefore be used on registers containing such Status Flags. The
CBI and SBI instructions work with registers 0x00 to 0x1F only.
9
2588ES–AVR–08/10
ATtiny261/461/861
5. 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
ADIW Rdl,K Add Immediate to Word Rdh:Rdl ← Rdh:Rdl + K Z,C,N,V,S 2
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
SBIW Rdl,K Subtract Immediate from Word Rdh:Rdl ← Rdh:Rdl - K Z,C,N,V,S 2
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 ← 0xFF − Rd Z,C,N,V 1
NEG Rd Two’s Complement Rd ← 0x00 − 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 • (0xFF - 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 ← 0xFF None 1
BRANCH INSTRUCTIONS
RJMP k Relative Jump PC ← PC + k + 1 None 2
IJMP Indirect Jump to (Z) PC ← Z None 2
RCALL k Relative Subroutine Call PC ← PC + k + 1 None 3
ICALL Indirect Call to (Z) PC ← ZNone3
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 1/2/3
CP Rd,Rr Compare Rd − Rr Z, N,V,C,H 1
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
SBRC Rr, b Skip if Bit in Register Cleared if (Rr(b)=0) PC ← PC + 2 or 3 None 1/2/3
SBRS Rr, b Skip if Bit in Register is Set if (Rr(b)=1) PC ← PC + 2 or 3 None 1/2/3
SBIC P, b Skip if Bit in I/O Register Cleared if (P(b)=0) PC ← PC + 2 or 3 None 1/2/3
SBIS P, b Skip if Bit in I/O Register is Set if (P(b)=1) PC ← PC + 2 or 3 None 1/2/3
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
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
BIT AND BIT-TEST INSTRUCTIONS
SBI P,b Set Bit in I/O Register I/O(P,b) ← 1None2
CBI P,b Clear Bit in I/O Register I/O(P,b) ← 0None2
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
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ATtiny261/461/861
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) ← TNone1
SEC Set Carry C ← 1C1
CLC Clear Carry C ← 0 C 1
SEN Set Negative Flag N ← 1N1
CLN Clear Negative Flag N ← 0 N 1
SEZ Set Zero Flag Z ← 1Z1
CLZ Clear Zero Flag Z ← 0 Z 1
SEI Global Interrupt Enable I ← 1I1
CLI Global Interrupt Disable I ← 0 I 1
SES Set Signed Test Flag S ← 1S1
CLS Clear Signed Test Flag S ← 0 S 1
SEV Set Twos Complement Overflow. V ← 1V1
CLV Clear Twos Complement Overflow V ← 0 V 1
SET Set T in SREG T ← 1T1
CLT Clear T in SREG T ← 0 T 1
SEH Set Half Carry Flag in SREG H ← 1H1
CLH Clear Half Carry Flag in SREG H ← 0 H 1
DATA TRANSFER INSTRUCTIONS
MOV Rd, Rr Move Between Registers Rd ← Rr None 1
MOVW Rd, Rr Copy Register Word Rd+1:Rd ← Rr+1:Rr None 1
LDI Rd, K Load Immediate Rd ← KNone1
LD Rd, X Load Indirect Rd ← (X) None 2
LD Rd, X+ Load Indirect and Post-Inc. Rd ← (X), X ← X + 1 None 2
LD Rd, - X Load Indirect and Pre-Dec. X ← X - 1, Rd ← (X) None 2
LD Rd, Y Load Indirect Rd ← (Y) None 2
LD Rd, Y+ Load Indirect and Post-Inc. Rd ← (Y), Y ← Y + 1 None 2
LD Rd, - Y Load Indirect and Pre-Dec. Y ← Y - 1, Rd ← (Y) None 2
LDD Rd,Y+q Load Indirect with Displacement Rd ← (Y + q) None 2
LD Rd, Z Load Indirect Rd ← (Z) None 2
LD Rd, Z+ Load Indirect and Post-Inc. Rd ← (Z), Z ← Z+1 None 2
LD Rd, -Z Load Indirect and Pre-Dec. Z ← Z - 1, Rd ← (Z) None 2
LDD Rd, Z+q Load Indirect with Displacement Rd ← (Z + q) None 2
LDS Rd, k Load Direct from SRAM Rd ← (k) None 2
ST X, Rr Store Indirect (X) ← Rr None 2
ST X+, Rr Store Indirect and Post-Inc. (X) ← Rr, X ← X + 1 None 2
ST - X, Rr Store Indirect and Pre-Dec. X ← X - 1, (X) ← Rr None 2
ST Y, Rr Store Indirect (Y) ← Rr None 2
ST Y+, Rr Store Indirect and Post-Inc. (Y) ← Rr, Y ← Y + 1 None 2
ST - Y, Rr Store Indirect and Pre-Dec. Y ← Y - 1, (Y) ← Rr None 2
STD Y+q,Rr Store Indirect with Displacement (Y + q) ← Rr None 2
ST Z, Rr Store Indirect (Z) ← Rr None 2
ST Z+, Rr Store Indirect and Post-Inc. (Z) ← Rr, Z ← Z + 1 None 2
ST -Z, Rr Store Indirect and Pre-Dec. Z ← Z - 1, (Z) ← Rr None 2
STD Z+q,Rr Store Indirect with Displacement (Z + q) ← Rr None 2
STS k, Rr Store Direct to SRAM (k) ← Rr None 2
LPM Load Program Memory R0 ← (Z) None 3
LPM Rd, Z Load Program Memory Rd ← (Z) None 3
LPM Rd, Z+ Load Program Memory and Post-Inc Rd ← (Z), Z ← Z+1 None 3
SPM Store Program Memory (z) ← R1:R0 None
IN Rd, P In Port Rd ← PNone1
OUT P, Rr Out Port P ← Rr None 1
PUSH Rr Push Register on Stack STACK ← Rr None 2
POP Rd Pop Register from Stack Rd ← STACK None 2
MCU CONTROL INSTRUCTIONS
NOP No Operation None 1
SLEEP Sleep (see specific descr. for Sleep function) None 1
WDR Watchdog Reset (see specific descr. for WDR/Timer) None 1
BREAK Break For On-chip Debug Only None N/A
Mnemonics Operands Description Operation Flags #Clocks
11
2588ES–AVR–08/10
ATtiny261/461/861
6. Ordering Information
Notes: 1. These devices can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering informa-
tion and minimum quantities.
2. All packages are Pb-free, halide-free and fully green and they comply with the European directive for Restriction of Hazard-
ous Substances (RoHS).
3. For Speed vs. VCC, see Figure 19.3 on page 188.
4. Code indicators:
– U: matte tin
– R: tape & reel
6.1 ATtiny261
Speed (MHz)(3) Power Supply (V) Ordering Code(4) Package(2) Operational Range
10 1.8 - 5.5
ATtiny261V-10MU
ATtiny261V-10MUR
ATtiny261V-10PU
ATtiny261V-10SU
ATtiny261V-10SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
20 2.7 - 5.5
ATtiny261-20MU
ATtiny261-20MUR
ATtiny261-20PU
ATtiny261-20SU
ATtiny261-20SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
Package Type
32M1-A 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm, Micro Lead Frame Package (MLF)
20P3 20-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
20S2 20-lead, 0.300" Wide, Plastic Gull Wing Smal Outline Package (SOIC)
12
2588ES–AVR–08/10
ATtiny261/461/861
Notes: 1. These devices can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering informa-
tion and minimum quantities.
2. All packages are Pb-free, halide-free and fully green and they comply with the European directive for Restriction of Hazard-
ous Substances (RoHS).
3. For Speed vs. VCC, see Figure 19.3 on page 188.
4. Code indicators:
– U: matte tin
– R: tape & reel
6.2 ATtiny461
Speed (MHz)(3) Power Supply (V) Ordering Code(4) Package(2) Operational Range
10 1.8 - 5.5
ATtiny461V-10MU
ATtiny461V-10MUR
ATtiny461V-10PU
ATtiny461V-10SU
ATtiny461V-10SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
20 2.7 - 5.5
ATtiny461-20MU
ATtiny461-20MUR
ATtiny461-20PU
ATtiny461-20SU
ATtiny461-20SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
Package Type
32M1-A 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm, Micro Lead Frame Package (MLF)
20P3 20-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
20S2 20-lead, 0.300" Wide, Plastic Gull Wing Smal Outline Package (SOIC)
13
2588ES–AVR–08/10
ATtiny261/461/861
Notes: 1. These devices can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering informa-
tion and minimum quantities.
2. All packages are Pb-free, halide-free and fully green and they comply with the European directive for Restriction of Hazard-
ous Substances (RoHS).
3. For Speed vs. VCC, see Figure 19.3 on page 188.
4. Code indicators:
– U: matte tin
– R: tape & reel
6.3 ATtiny861
Speed (MHz)(3) Power Supply (V) Ordering Code(4) Package(2) Operational Range
10 1.8 - 5.5
ATtiny861V-10MU
ATtiny861V-10MUR
ATtiny861V-10PU
ATtiny861V-10SU
ATtiny861V-10SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
20 2.7 - 5.5
ATtiny861-20MU
ATtiny861-20MUR
ATtiny861-20PU
ATtiny861-20SU
ATtiny861-20SUR
32M1-A
32M1-A
20P3
20S2
20S2
Industrial
(-40°C to +85°C)(1)
Package Type
32M1-A 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm, Micro Lead Frame Package (MLF)
20P3 20-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP)
20S2 20-lead, 0.300" Wide, Plastic Gull Wing Smal Outline Package (SOIC)
14
2588ES–AVR–08/10
ATtiny261/461/861
7. Packaging Information
7.1 32M1-A
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
32M1-A, 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm, D
32M1-A
8/19/04
3.10 mm Exposed Pad, Micro Lead Frame Package (MLF)
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
D1
D
E1 E
e
b
A3
A2
A1
A
D2
E2
0.08 C
L
1
2
3
P
P
0
1
2
3
A 0.80 0.90 1.00
A1 – 0.02 0.05
A2 – 0.65 1.00
A3 0.20 REF
b 0.18 0.23 0.30
D 5.00 BSC
D1 4.75 BSC
D2 2.95 3.10 3.25
E 5.00 BSC
E1 4.75BSC
E2 2.95 3.10 3.25
e 0.50 BSC
L 0.30 0.40 0.50
P – – 0.60
– – 12o
Note: JEDEC Standard MO-220, Fig. 2 (Anvil Singulation), VHHD-2.
TOP VIEW
SIDE VIEW
BOTTOM VIE W
0
Pin 1 ID
Pin #1 Notch
(0.20 R)
K 0.20 – –
K
K
15
2588ES–AVR–08/10
ATtiny261/461/861
7.2 20P3
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
20P3, 20-lead (0.300"/7.62 mm Wide) Plastic Dual
Inline Package (PDIP) C
20P3
1/12/04
PIN
1
E1
A1
B
E
B1
C
L
SEATING PLANE
A
D
e
eB
eC
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A – – 5.334
A1 0.381 – –
D 25.493 – 25.984 Note 2
E 7.620 – 8.255
E1 6.096 – 7.112 Note 2
B 0.356 – 0.559
B1 1.270 – 1.551
L 2.921 – 3.810
C 0.203 – 0.356
eB – – 10.922
eC 0.000 – 1.524
e 2.540 TYP
Notes: 1. This package conforms to JEDEC reference MS-001, Variation AD.
2. Dimensions D and E1 do not include mold Flash or Protrusion.
Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
16
2588ES–AVR–08/10
ATtiny261/461/861
7.3 20S2
17
2588ES–AVR–08/10
ATtiny261/461/861
8. Errata
8.1 Errata ATtiny261
The revision letter in this section refers to the revision of the ATtiny261 device.
8.1.1 Rev A
No known errata.
8.2 Errata ATtiny461
The revision letter in this section refers to the revision of the ATtiny461 device.
8.2.1 Rev B
Yield improvement. No known errata.
8.2.2 Rev A
No known errata.
8.3 Errata ATtiny861
The revision letter in this section refers to the revision of the ATtiny861 device.
8.3.1 Rev B
No known errata.
8.3.2 Rev A
Not sampled.
18
2588ES–AVR–08/10
ATtiny261/461/861
9. Datasheet Revision History
Please note that the referring page numbers in this section refer to the complete document.
9.1 Rev. 2588E – 08/10
Added tape and reel in “Ordering Information” on page 227. Clarified Section 6.4 “Clock Output
Buffer” on page 32. Removed text "Not recommended for new design" from cover page.
9.2 Rev. 2588D – 06/10
1. Removed “Preliminary” from cover page.
2. Added clarification before Table 6-10, “Capacitance for Low-Frequency Crystal Oscilla-
tor,” on page 29.
3. Updated Figure 15-1 “Analog to Digital Converter Block Schematic” on page 143,
changed INTERNAL 1.18V REFERENCE to 1.1V.
4. Updated Table 18-8, “No. of Words in a Page and No. of Pages in the EEPROM,” on
page 173, No. of Pages from 64 to 32 for ATtiny261.
5. Adjusted notes in Table 19-1, “DC Characteristics. TA = -40°C to +85°C, VCC = 1.8V to
5.5V (unless otherwise noted).,” on page 187.
9.3 Rev. 2588C – 10/09
1. Updated document template. Re-arranged some sections.
2. Changed device status to "Not Recommended for New Designs".
3. Added Sections:
–“Data Retention” on page 6
–“Clock Sources” on page 25
–“Low Level Interrupt” on page 51
–“Prescaling and Conversion Timing” on page 145
–“Clock speed considerations” on page 131
4. Updated Sections:
–“Code Examples” on page 6
–“High-Frequency PLL Clock” on page 26
–“Normal Mode” on page 99
–“Features” on page 142
–“Temperature Measurement” on page 154
–“Limitations of debugWIRE” on page 164
–Step 1. on page 174
–“Programming the Flash” on page 180
–“System and Reset Characteristics” on page 190
5. Added Figures:
–“Flash Programming Waveforms” on page 182
–“Reset Pin Output Voltage vs. Sink Current (VCC = 3V)” on page 209
–“Reset Pin Output Voltage vs. Sink Current (VCC = 3V)” on page 209
–“Reset Pin Output Voltage vs. Sink Current (VCC = 3V)” on page 209
–“Reset Pin Output Voltage vs. Sink Current (VCC = 3V)” on page 209
19
2588ES–AVR–08/10
ATtiny261/461/861
–“Bandgap Voltage vs. Supply Voltage (VCC).” on page 216
6. Updated Figures:
–“Block Diagram” on page 4
–“Clock Distribution” on page 24
7. Added Table:
–“Capacitance for Low-Frequency Crystal Oscillator” on page 29
8. Updated Tables:
–“Start-up Times for the Internal Calibrated RC Oscillator Clock Selection” on page 28
–“Start-up Times for the 128 kHz Internal Oscillator” on page 29
–“Active Clock Domains and Wake-up Sources in Different Sleep Modes” on page 36
–“Serial Programming Characteristics, TA = -40°C to +85°C, VCC = 1.8 - 5.5V (Unless
Otherwise Noted)” on page 193
9. Updated Register Descriptions:
–“TCCR1A – Timer/Counter1 Control Register A” on page 112
–“TCCR1C – Timer/Counter1 Control Register C” on page 117
–“ADMUX – ADC Multiplexer Selection Register” on page 155
10. Updated assembly program example in section “Write” on page 17.
11. Updated “DC Characteristics. TA = -40°C to +85°C, VCC = 1.8V to 5.5V (unless other-
wise noted).” on page 187.
9.4 Rev. 2588B – 11/06
1. Updated “Ordering Information” on page 227.
2. Updated “Packaging Information” on page 230.
9.5 Rev. 2588A – 10/06
1. Initial Revision.
2588ES–AVR–08/10
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