Datasheet

4
2588FS–AVR–06/2013
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
DATA BU S
PA[0..7]PB[0..7]
11
RESET
XTAL[1..2]
CPU
3