Microchip Technology, Inc. AT89C51RC2

High-performance, 8-bit microcontroller with 32KB flash. It retains all features of the 80C52 with 256 Bytes of internal RAM, a 9-source 4-level interrupt controller, and three timer/counters. It features a programmable counter array, an XRAM of 1024 bytes, hardware watchdog timer, keyboard interface, SPI interface, versatile serial channel that facilitates multiprocessor communication (EUART), and a speed improvement mechanism (X2 mode). We recommend implementing an external brown-out to prevent any flash/EEPROM corruption during power-on or power-off.