Overview
ATtiny261A/461A/861A are low-power CMOS 8-bit microcontrollers based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the devices achieve 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
   – Up to 20 MIPS Throughput at 20 MHz
• High Endurance Non-volatile Memory Segments
   – 2/4/8K Bytes of In-System Self-Programmable Flash Program Memory
• Endurance: 10,000 Write/Erase Cycles
   – 128/256/512 Bytes of In-System Programmable EEPROM
• Endurance: 100,000 Write/Erase Cycles
   – 128/256/512 Bytes of Internal SRAM
   – Data retention: 20 Years at 85°C / 100 Years at 25°C
   – In-System Programmable via SPI Port
   – Programming Lock for Software Security
• Peripheral Features
   – One 8/16-bit Timer/Counter with Prescaler
   – One 8/10-bit High Speed Timer/Counter with 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
   – Interrupt and Wake-up on Pin Change
• Special Microcontroller Features
   – debugWIRE On-Chip Debug System
   – Power-on Reset and Programmable Brown-out Detection
   – Internal Calibrated Oscillator
   – External and Internal Interrupt Sources
   – Four Sleep Modes: Low Power Idle, ADC Noise Reduction, Standby and Power Down
   – On-Chip Temperature Sensor
• I/O and Packages
   – 16 Programmable I/O Lines
   – 20-pin PDIP, 20-pin SOIC, 20-pin TSSOP and 32-pad MLF
• Operating Voltage
   – 1.8 – 5.5V
• Speed Grades
   – 0 – 4 MHz @ 1.8 – 5.5V
   – 0 – 10 MHz @ 2.7 – 5.5V
   – 0 – 20 MHz @ 4.5 – 5.5V
• Power Consumption at 1 MHz, 1.8V, 25°C
   – Active: 200 µA
   – Power-Down Mode: 0.1 µA