DESCRIPTION

The DS87C520/DS83C520 EPROM/ROM high-speed microcontrollers are fast 8051-compatible microcontrollers. They feature a redesigned processor core without wasted clock and memory cycles. As a result, the devices execute every 8051 instruction between 1.5 and 3 times faster than the original for the same crystal speed. Typical applications will see a speed improvement of 2.5 times using the same code and the same crystal. The DS87C520/DS83C520 offer a maximum crystal speed of 33MHz, resulting in apparent execution speeds of 82.5MHz (approximately 2.5X).

FEATURES

■ 80C52 Compatible

8051 Pin- and Instruction-Set Compatible

Four 8-Bit I/O Ports

Three 16-Bit Timer/Counters

256 Bytes Scratchpad RAM

■ Large On-Chip Memory

16kB Program Memory

1kB Extra On-Chip SRAM for MOVX

■ ROMSIZE Feature

Selects Internal ROM Size from 0 to 16kB

Allows Access to Entire External Memory Map

Dynamically Adjustable by Software

Useful as Boot Block for External Flash

■ High-Speed Architecture

4 Clocks/Machine Cycle (8051 = 12)

Runs DC to 33MHz Clock Rates

Single-Cycle Instruction in 121ns

Dual Data Pointer

Optional Variable Length MOVX to Access Fast/Slow RAM/Peripherals

■ Power Management Mode

Programmable Clock Source to Save Power

CPU Runs from (crystal/64) or (crystal/1024)

Provides Automatic Hardware and Software Exit

■ EMI Reduction Mode Disables ALE

■ Two Full-Duplex Hardware Serial Ports

■ High Integration Controller Includes:

Power-Fail Reset

Early-Warning Power-Fail Interrupt

Programmable Watchdog Timer

■ 13 Interrupt Sources with Six External

■ Available in 40-pin PDIP, 44-Pin PLCC, 44-Pin TQFP, and 40-Pin Windowed CERDIP

■ Factory Mask DS83C520 or EPROM (OTP) DS87C520