Overview
The ATtiny261/461/861 is a low-power CMOS 8-bit microcontroller 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.

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 (ATtiny261/461/861) Endurance: 10,000 Write/Erase Cycles
   – 128/256/512 Bytes In-System Programmable EEPROM (ATtiny261/461/861) Endurance: 100,000 Write/Erase Cycles
   – 128/256/512 Bytes Internal SRAM (ATtiny261/461/861)
   – Programming Lock for Self-Programming Flash Program and 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
   – Universal Serial Interface with Start Condition Detector
   – 10-bit ADC
      11 Single Ended Channels
      16 Differential ADC Channel Pairs
      15 Differential ADC Channel Pairs with Programmable Gain (1x, 8x, 20x, 32x)
   – Programmable Watchdog Timer with Separate On-chip Oscillator
   – On-chip Analog Comparator
• 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, and Power-down Modes
   – Enhanced Power-on Reset Circuit
   – Programmable Brown-out Detection Circuit
   – Internal Calibrated Oscillator
• I/O and Packages
   – 16 Programmable I/O Lines
   – 20-pin SOIC, 32-pad MLF and 20-lead TSSOP
• Operating Voltage:
   – 2.7 - 5.5V for ATtiny261/461/861
• Speed Grade:
   – ATtiny261/461/861: 0 - 8 MHz @ 2.7 - 5.5V, 0 - 16 MHz @ 4.5 - 5.5V
   – Operating temperature: Automotive (-40°C to +125°C)
• Low Power Consumption
   – Active Mode ATD On: 1 MHz, 2.7V, 25°C: 300 µA
   – Power-down Mode no Watchdog: 2.7V, 25°C: 0.12 µA