View w78e51b datasheet:

Preliminary W78E51B 8-BIT FLASH MICROCONTROLLER GENERAL DESCRIPTION The W78E51B is an 8-bit microcontroller which can accommodate a wider frequency range with low power consumption. The instruction set for the W78E51B is fully compatible with the standard 8051. The W78E51B contains an 4K bytes FLASH ROM (Multiple-Time Programmable ROM); a 128 bytes RAM; four 8-bit bi-directional and bit-addressable I/O ports; an additional 4-bit I/O port P4; two 16-bit timer/counters; a hardware watchdog timer and a serial port. These peripherals are supported by seven sources two-level interrupt capability. To facilitate programming and verification, the FLASH-ROM inside the W78E51B allows the program memory to be programmed and read electronically. Once the code is confirmed, the user