This application note describes how to use the Keil µVision2 suite of tools to debug an application for the Ultra-High-Speed Flash family of microcontrollers, which includes the DS89C420, DS89C430, DS89C440, and DS89C450. This process involves loading a debug monitor application into the DS89C4X0 which communicates with Keil µVision2 over a selected serial port. ……