5

7753BS–AVR–08/08

ATtiny261/461/861

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 con-

ventional CISC microcontrollers.

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, 6 general purpose I/O lines, 32

general purpose working registers, one 8-bit Timer/Counter with compare modes, one 8-bit high

speed Timer/Counter, Universal Serial Interface, Internal and External Interrupts, a 4-channel,

10-bit ADC, a programmable Watchdog Timer with internal Oscillator, and three software select-

able power saving modes. The Idle mode stops the CPU while allowing the SRAM,

Timer/Counter, ADC, Analog Comparator, and Interrupt system to continue functioning. The

Power-down mode saves the register contents, disabling all chip functions until the next Inter-

rupt or Hardware Reset. The ADC Noise Reduction mode stops the CPU and all I/O modules

except ADC, to minimize switching noise during ADC conversions.

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 with a full suite of program and system development

tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators, In-Circuit Emu-

lators, and Evaluation kits.