摘要
针对大多数嵌入式系统键盘显示电路复杂、不灵活、维护困难等问题,结合指纹识别系统在汽车安全领域的应用,介绍了基于I2C总线的数码管显示驱动和键盘扫描控制芯片CH452S以及扩展口器件PCF8574AP在指纹识别系统键盘显示接口中的应用,包括硬件电路连接和软件程序设计。采用I2C总线,不仅占用端口资源少,电路结构简单,而且易于电路扩展与系统升级。
In order to solve the problems of complex circuit, inflexible structure and difficult maintenance in keyboard and display interface of embedded system, combining with the application of FIS（fmgerprint identification system） in vehicle security system, it introduces PCF8574AP and CH452S used in keyboard and display interface of FIS base on I2C bus, including hardware connection and software program. By using I2C bus, it has advantages of taking up few 110 ports, simple circuit structure, easy circuit extending and system upgrading.
