The high-performance, low-power Atmel AVR 8-bit microcontroller family features an advanced RISC architecture – 131 powerful instructions – most single-clock cycle execution – 32 x 8 general-purpose working registers – fully static operation – up to 20 MIPS throughput at 20MHz – on-chip 2-cycle multiplier. High-endurance non-volatile memory segments – 4/8/16/32KBytes of in-system self-programmable Flash program memory – 256/512/512/1KBytes EEPROM – 512/1K/1K/2KBytes internal SRAM – write/erase cycles: 10,000 Flash/100,000 EEPROM – data retention: 20 years at 85°C/100 years at 25°C – optional boot code section with independent lock bits. In-system programming by on-chip boot program for true read-while-write operation. Software security with programmable lock bits. Atmel QTouch library support – capacitive touch buttons, sliders, and wheels – QTouch and QMatrix acquisition – up to 64 sense channels. Peripheral features – two 8-bit timer/counters with separate prescaler and compare mode – one 16-bit timer/counter with separate prescaler, compare mode, and capture mode – real-time counter with separate oscillator – six PWM channels – 8-channel 10-bit ADC (TQFP and QFN/MLF packages) for temperature measurement – 6-channel 10-bit ADC (PDIP package) for temperature measurement – programmable serial USART – master/slave SPI serial interface – byte-oriented 2-wire serial interface (Philips I2C compatible) – programmable watchdog timer with separate on-chip oscillator – on-chip analog comparator – pin change interrupt and wake-up. Special microcontroller features – power-on reset and programmable brown-out detection – internal calibrated oscillator – external and internal interrupt sources – six sleep modes: idle, ADC noise reduction, power-save, power-down, standby, and extended standby. I/O and packages – 23 programmable I/O lines – 28-pin PDIP, 32-lead TQFP, 28-pad QFN/MLF, and 32-pad QFN/MLF.