There are many reasons to upgrade older 8051 designs that use high-speed microcontrollers
(DS80C310/DS80C320/DS80C323/DS8xC520) to the newer ultra-high-speed flash microcontrollers
(DS89C430/DS89C450). Incentives to upgrade include higher performance, additional features and
peripherals, and the flexibility of internal flash memory.

This application note discusses some important differences between the two microcontroller families and explains how to upgrade from the high-speed to the ultra-high-speed devices.