Specifications of Atmel 8 Bit 28 Pins Microcontroller ATMEGA328P Microchip: 4.5V-5.5V operating range Up to 20MHz Part: ATMEGA328P-AU 32kB Flash program memory 1kB EEPROM 2kB Internal SRAM Two8-bit Timer/Counters One16-bit Timer/Counter RTC with separate oscillator 6 PWM Channels 8 Channel 10-bit ADC Serial USART Master/Slave SPI interface 2-wire (I2C) interface Watchdog timer Analog comparator 23 IO lines Data retention: 20 years at 85oC/ 100 years at 25oC