The AT8xC5112 retains all the features of the standard 80C51 with 8 Kbytes ROM/OTP program memory, 256 bytes of internal RAM, a 8-source, 4-level interrupt system, an on-chip oscillator and two timer/counters. The AT8xC5112 is dedicated for analog interfacing applications. For this, it has a 10bit, 8 channels A/D converter and a five channels Programmable Counter Array. In addition, the AT8xC5112 has a Hardware Watchdog Timer, a versatile serial channel that facilitates multiprocessor communication (EUART) with an independent baud rate generator, a SPI serial bus controller and a X2 speed improvement mechanism. The X2 feature allows to keep the same CPU power at a divided by two oscillator frequency.