DESCRIPTION
The 87C654 Single-Chip 8-Bit Microcontroller is manufactured in an advanced CMOS process and is a derivative of the 80C51 microcontroller family. The 87C654 has the same instruction set as the 80C51. Two versions of the derivative exist:
83C654—16k bytes mask programmable ROM
87C654—EPROM version

This device provides architectural enhancements that make it applicable in a variety of applications for general control systems. The 87C654 contains a non-volatile 16k × 8 EPROM, a volatile 256 × 8 read/write data memory, four 8-bit I/O ports, two 16-bit timer/event counters (identical to the timers of the 80C51), a multi-source, two-priority-level, nested interrupt structure, an I2C interface, UART and on-chip oscillator and timing circuits. For systems that require extra capability, the 87C654 can be expanded using standard TTL compatible memories and logic.
The device also functions as an arithmetic processor having facilities for both binary and BCD arithmetic plus bit-handling capabilities.
The instruction set consists of over 100 instructions: 49 one-byte, 45 two-byte and 17 three-byte. With a 16MHz crystal, 58% of the instructions are executed in 0.75µs and 40% in 1.5µs. Multiply and divide instructions require 3µs.

FEATURES
• 80C51 central processing unit
• 16k × 8 EPROM expandable externally to 64k bytes
• 256 × 8 RAM, expandable externally to 64k bytes
• Two standard 16-bit timer/counters
• Four 8-bit I/O ports
• I2C-bus serial I/O port with byte oriented master and slave functions
• Full-duplex UART facilities
• Power control modes
   – Idle mode
   – Power-down mode
• Five package styles
• Extended temperature range
• OTP package available
• Two speed ranges
   – 16MHz
   – 20MHz