GENERAL DESCRIPTION
The P83C524 and P83C528 single-chip 8-bit microcontrollers are manufactured in an advanced CMOS process and are derivatives of the PCB80C51 microcontroller family. These devices provide architectural enhancements that make them applicable in a variety of applications in general control systems, especially in those systems which need a large ROM and RAM capacity on chip.
The P83C524 and P83C528 contain a non-volatile 16 k × 8 respectively 32 k × 8 read-only program memory, a volatile 512 bytes × 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 16-bit timer (identical to the timer 2 of the 8052), a multi-source, two-priority-level, nested interrupt structure, two serial interfaces (UART and bit-level I2C-bus), a watchdog timer (WDT) with a separate oscillator, an on-chip oscillator and timing circuits. For systems that require extra capability, the P83C524 and P83C528 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 P83C524 and P83C528 have the same instruction set as the PCB80C51 which consists of over 100 instructions: 49 one-byte, 46 two-byte and 16 three-byte. With a 16 MHz crystal, 58% of the instructions are executed in 750 ns and 40% in 1.5 µs. Multiply and divide instructions require 3 µs.

FEATURES
• 80C51 CPU
• 32 kbytes on-chip ROM, expandable externally to 64 kbytes Program Memory address space
• P83C524:
   – 16 kbytes on-chip ROM, expandable externally from 32 kbytes to 64 kbytes Program Memory address space (address space 16 k to 32 k not usable)
• P80C528:
   – ROMless version of P83C528
• P83C528:
   – 32 kbytes on-chip ROM, expandable externally from 32 kbytes to 64 kbytes Program Memory address space
• EPROM versions are available: see separate data sheet P87C524 and P87C528
• 512 bytes on-chip RAM, expandable externally to 64 kbytes Data Memory address space
• Four 8-bit I/O ports
• Full-duplex UART compatible with the standard 80C51 and the 8052
• Two standard 16-bit timer/counters
• An additional 16-bit timer (functionally equivalent to the timer 2 of the 8052)
• On-chip Watchdog Timer (WDT) with an own oscillator
• Bit-level I2C-bus hardware serial I/O Port
• 7-source and 7-vector interrupt structure with 2 priority levels
• Up to 3 external interrupt request inputs
• Two programmable power reduction modes (Idle and Power-down)
• Termination of Idle mode by any interrupt, external or WDT (watchdog) reset
• Wake-up from Power-down by external interrupt, external or WDT reset
• ROM code protection
• XTAL frequency range: 3.5 MHz to 16 MHz and 3.5 MHz to 24 MHz
• All packaging pin-outs fully compatible to the standard 8051/8052.