Design and application of CPLD in vehicle exhaust gas measurer

New kind of vehicle exhaust gas measurer based on CPLD is designed. Hardware circuit block diagram of exhaust gas measurer is introduced, since P89C668 single chip machine has only a UART, ISP programming port, micro-printer interface and last position machine communication port need to serial communication. To solve this contradiction, is choiced interface design for EPM7128SLC84-15 chip, which single chip machine control and use one function. QUARTUS II software development tool and VHDL program language are adopted. Modularization programming mode of CPLD is compiled, which every module has a corresponding VHDL file. The results show that design cost is reduced 20% and development cycle of vehicle exhaust gas measurer is reduced 14 month, vehicle exhaust gas measurer can meet expectant request.