DESCRIPTION
The Philips 8XC451 is an I/O expanded single-chip microcontroller fabricated with Philips high-density CMOS technology. Philips epitaxial substrate minimizes latch-up sensitivity. The 8XC451 (includes the 80C451, 87C451 and 83C451) is a functional extension of the 87C51 microcontroller with three additional I/O ports and four I/O control lines for a total of 68 pins. Four control lines associated with port 6 facilitate high-speed asynchronous I/O functions. The 8XC451 includes a 4k × 8 ROM (83C451) EPROM (87C451), a 128 × 8 RAM, 56 I/O, two 16-bit timer/counters, a five source, two priority level, nested interrupt structure, a serial I/O port for either a full duplex UART, I/O expansion, or multi-processor communications, and on-chip oscillator and clock circuits. The 80C451 ROMless version includes all of the 83C451 features except the on-board 4k × 8 ROM. Idle mode freezes the CPU while allowing the RAM, timers, serial port, and interrupt system to continue functioning. Power-down mode freezes the oscillator, causing all other chip functions to be inoperative while maintaining the RAM contents.
NXP Semiconductors
