The Key Technology of Designing the Universal Programmer for Freescale HCS12 Serial MCUs

摘要

For implementing on-line programming of Freescale HCS12 series MCU, designing a common downloading programmer which functions include chip selection, erase and write operations. Designing a database where Freescale HCS12 MCU Flash difference parameter values placed, so achieving HCS12 MCU family online programming versatility. Erase and write machine codes are provided in the RAM area of Flash memory, these codes will be run at high voltage, these codes are relocated from Flash to RAM area for improving flash operation stability during the high voltage. According to BDM communication theory, we have developed a separate BDM serial communication program, the target device only receives the user code from the programmer, programmer does not need send opcode and the address information, not waiting for a command, so, increasing the erase and write speed, the programmer has the versatility and easily using.