DESCRIPTION
The DS87C520/DS83C520 EPROM/ROM High-Speed Micro is a fast 8051-compatible microcontroller. It features a redesigned processor core without wasted clock and memory cycles. As a result, it executes 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 offers a maximum crystal speed of 33 MHz, resulting in apparent execution speeds of 82.5 MHz (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 total interrupt sources with 6 external
■ Available in 40-pin PDIP, 44-pin PLCC, 44-pin TQFP, and 40-pin windowed CERDIP
■ Factory Mask DS83C520 or EPROM (OTP) DS87C520