基于MC9S12XS128的汽车BCM的设计

为某车型设计了一款车身中央控制器BCM，实现了门锁控制、灯光控制、雨刷控制、车窗控制、LIN通信、RKE通信等功能。BCM采用Freescale的S12系列16位微处理器MC9S12XS128进行设计，通过多路开关检测芯片MC33993进行IO扩展，解决了多路开关、处理器IO管脚有限条件下的开关信号采集，开关信号检测程序设计中采用通用结构体统一了各路开关信号的状态监测及变化捕捉功能的实现，提高了代码效率及运行的稳定性。同时还叙述了BCM的硬件结构，根据BCM的工作方式设计了软件流程。

Abstract:

 A body central controller BCM was designed， which realized the door lock control， lighting control， wiper control， window control， LIN communication， RKE communications and other functions. BCM used Freescale’s S12 16’bit microprocessor MC9S12XS128 for its design， and used multiple switch detection chip MC33993 for IO expansion to solve switch detect in multi switch and limited IO pins condition. In switch detect programming， a common structure was adopted to implement switch signals status monitoring and its change capture， which improved the code efficiency and operational stability. Also BCM hardware architecture was described， and software process based on BCM’s work mode was designed