IN87C51N

The IN87C51N is the EPROM version of the 80C51. Microcontroller fabricated with high-density CMOS technology. It contains 4K bytes of on chip Program memory that can be electrically programmed The 80C51 contains a 4k x 8 ROM , a 128 x 8 RAM , 32 I/O lines, two 16-bit counter/timers, a five-source, two-priority level nested interrupt structure, a serial I/O port for  either multi-processor communications, I/O expansion or full duplex UART, and on-chip oscillator and clock circuits.

The IN87C51N has two software selectable modes of power reduction  idle mode and power-down mode. The idle mode freezes the CPU while allowing the RAM, timers, serial port, and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator, causing all other chip functions to be inoperative.