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).
The DS87C520/DS83C520 are pin compatible with all three packages of the standard 8051, and include standard resources such as three timer/counters, serial port, and four 8-bit I/O ports. They feature 16kB of EPROM or mask ROM with an extra 1kB of data RAM. Both OTP and windowed packages are available.
Besides greater speed, the microcontroller includes a second full hardware serial port, seven additional interrupts, programmable Watchdog Timer, Brownout Monitor, and Power-Fail Reset. The device also provides dual data pointers (DPTRs) to speed block data memory moves. It also can adjust the speed of MOVX data memory access from two to nine machine cycles for flexibility in selecting external memory and peripherals.