The OSD Design Of Vehicle Imfomation And Communication System Based On CPLD

This paper describes the design and realization of CPLD of vehicle information and communication system。This paper focuses on the OSD video signals process and human-machine interface。FPGA,Graph Control device and CPLD are available to design a external OSD control。According to the bill of material study, the CPLD solution is the lowest cost solution。MCU and CPLD can access the SRAM for OSD data via four different ways: latching data,using /WAIT signal of MCU,diable OSD diplay till whole frame data updated and MCU access SRAM during LCD line/filed blanking。Develop C code and then compile it to assembly code, figure out the numner of MCU instruction cycletime for MCU to transform one frame OSD data to SRAM。Select latching data as the CPLD core engine, as this mehod can reduce OSD data process cycle time and whole system will be more robuster。Base on the optimized OSD software architecture, it will reduce software development time of whole system,and will reduce manufacture test cycle time with buil-in OSD test patterns。Evaluated the external OSD control module with whole information and communication system, redesigned the video cable,added I2C bus buffer between OSD control module and LCD driver. Fixed the blurred image defect with optimized the font OSD library design。...