Design And Application Of MC9S12 Series MCU ISP System

Along with the widely application and popularization of high performance, low power loss MC9S12 series MCU, which newly promoted by Freescale semiconductor Inc., the paper thoroughly studied the MC9S12 Background Debug Mode (BDM); and analyzed MC9S12 work principle of In System Programming (ISP), in order to solve the problem of program upgrading to make electronic engineers use the MC9S12 series MCU in their applications more conveniently and fully exert the MCU's functions. Then the paper provided the developing plan of Procedure Downloads System for MC9S12 series MCU, the design and implementation from the aspect of overall, hardware and software. By compiling and composing MC9S12 monitor routine and PC software, program upgrading and debugging of MCU have been realized successfully. On the basis of analysing the operating principle of MC9S12 BDM module deeply, the communication function bunch has been used to solve the problem of communication with multi-bus frequency target MCU, and In System Programming with Flash in average pattern and protection pattern is implemented, which based on various Flash mechanisms.