摘 要： 一種采用高性能8位微控制器MC68HC908RF2與傳感器、射頻收發器相結合的汽車胎壓" title="胎壓">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" 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title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測" title="胎壓監測">胎壓監測系統的設計方案，描述了該監測系統的功能、硬件實現和軟件設計流程。
關鍵詞： MC68HC908RF2 胎壓監測系統 間接式TPMS 直接式TPMS ABS
自汽車誕生100多年來，汽車爆胎" title="爆胎">爆胎造成的重大交通事故一直是困擾汽車界的技術難題。尤其在汽車的高速行駛過程中，輪胎故障是所有駕駛者最為擔心和最難預防的，也是突發性交通事故發生的重要原因。據相關統計資料數據表明[1]，目前我國在高速公路上發生的交通事故有70%～80%是由于輪胎問題引起的，其中將近50%為爆胎事故。怎樣防止爆胎已成為安全駕駛的一個重要課題。據專家分析，保持標準的車胎氣壓行駛和及時發現車胎漏氣是防止爆胎的關鍵。為此，基于解決此類問題的各種胎壓監測系統[2](TPMS)產品應運而生。本文介紹的TPMS是一種主動安全技術產品，它采用無線傳輸技術，通過胎壓監測模塊和接收模塊" title="接收模塊">接收模塊，對在行使過程中的汽車輪胎氣壓、溫度實時自動地監測，對輪胎漏氣、低壓、溫度過高進行報警，即在發生事故前發出警報，提醒駕駛員采取措施，以防止爆胎事故的發生，為汽車駕駛者提供更可靠的保障。此外還有延長輪胎使用壽命，節省燃油的功能。
1 MC68HC908RF2芯片簡介
MC68HC908RF2[3]微控制器是FREESCALE公司生產的一款低成本、高性能的8位微控制器單元(MCU)，它是M68HC08家族中的成員之一，采用了增強型M68HC08中心處理單元(CPU08)，適用于多種模式、存儲尺寸和類型。這款MCU產品經過優化，實現了低功耗運行，采用小型的32針腳小外形四方扁平封裝(LQFP)，該封裝由兩部分組成，第一部分是2KB Flash HC08 MCU(部件編號MC68HC908RK2)；第二部分是射頻轉發器(部件編號MC33493)，在自由空間中能將數據傳輸幾百米，適用于汽車胎壓監測系統" title="汽車胎壓監測系統">汽車胎壓監測系統。
MC68HC908RF2的主要特性如下：
(1)高性能的M68HC08體系結構。
(2)完全向上兼容M6508、M146805和M68HC05系列的對象代碼。
(3)在3.3V供電時的最大內部總線頻率為4MHz。
(4)2KB的片上FLASH存儲器，128B的片上RAM。
(5)16位的2通道定時器接口模塊(TIM)。
(6)12個通用I/O口，帶鍵盤喚醒功能的6位鍵盤中斷。
(7)1個內置的高頻發射模塊UHF(MC33493模塊)。
(8)較寬的工作溫度范圍：-40°C～＋125°C。
2 汽車胎壓監測系統工作原理
本設計是在基于FREESCALE的MC68HC908RF2、MPXY8020A[4]、MC33594[5]等核心芯片以及優化解決方案的基礎上，設計的一套汽車胎壓監測報警系統，對高速行駛汽車的胎壓進行連續監測及預報，并記錄最后100秒的胎壓信息，為安全行車及行車管理提供依據。系統工作原理如圖1所示。
由圖1可知，該監測系統由胎壓監測模塊和中央接收模塊兩個主要部分組成。其中胎壓監測模塊安裝在汽車輪胎內，該模塊帶有傳感器和無線發射裝置，主要用來監測輪胎內的氣壓和溫度并把監測到的數據通過發射裝置發送給接收模塊；中央接收模塊安裝在駕駛室操作盤附近，帶有無線接收裝置、聲光報警模塊和液晶顯示模塊，無線接收裝置接收到胎壓監測模塊發送來的數據，將各輪胎的氣壓和溫度由液晶顯示模塊顯示，駕駛者通過顯示模塊即可掌握各個輪胎的氣壓和溫度狀況，當輪胎氣壓、溫度發生異常將要出現危險征兆時，就會通過聲光報警模塊自動報警，以提醒駕駛者減速慢行或做相應的檢查和檢修，從而保證行車的安全以及輪胎保持在正常運行狀態。此外，為了系統功能的更新和維護方便，該模塊還保留了與上位機的USART通信接口。
3 汽車胎壓監測系統硬件設計
汽車胎壓監測系統硬件設計主要分為胎壓監測模塊和中央接收模塊兩大部分，下面介紹具體實現。
3.1 胎壓監測模塊硬件設計
由圖2可知，胎壓監測模塊硬件部分主要由傳感器、控制器和天線匹配網絡三部分組成。其中傳感器采用的是具有測量溫度、壓力功能的MPXY8020A。該傳感器將一個變容壓力傳感元件、一個溫度傳感元件和一個接口電路(帶喚醒功能)集成在同一芯片中；具有電源管理和數字輸出功能，其低功耗的特殊功能是專門為TPMS而設計，內部的介質保護過濾器可以使其硅片免受環境影響。MPXY8020A根據對S0、S1管腳的不同配置有4種操作模式：待機/復位模式、測量氣壓模式、測量溫度模式和輸出數據讀取模式。與控制器MC68HC908RF2共有6條引腳連線，其中2個引腳用于控制其操作模式，2個引腳用于數據串行交換，1個引腳用于喚醒控制器。 MPXY8020A還具有復位功能，該引腳作為一個輸出端子，定時向控制器發送復位信號，確保模塊可靠工作。
控制器MC68HC908RF2將8位Flash單片機(MCU)和UHF發射器(MC33493)集成在同一芯片內。MCU連接傳感器，定期檢查氣壓和溫度數據。發射器雖然與MCU集成在一起，但其工作完全由MCU控制，設定其工作頻率和模式，從而控制數據的發送。匹配網絡主要是確保由MC33493傳送來的數據能以無線通信的標準發送出去。
3.2 中央接收模塊硬件設計
中央接收模塊通過指示燈閃爍或液晶顯示來告知駕駛員車輛各輪胎當前的壓力、溫度是否異常。中央接收模塊硬件結構如圖3所示，主要由無線接收部分、主控制器以及相關的外圍器件組成。無線接收部分由高集成UHF接收器MC33594及其匹配網絡組成；MC33594具有接收并解調OOK或FSK調制的Manchester(曼徹斯特編碼)數據的功能，同時通過其SPI總線接口可與主控制器進行數據交換；若采用FSK調制，MC33594可支持數據管理器——Manchester數據解碼器，如果有匹配的天線，其靈敏度可以達到-103dBm。
主控制器的選擇與TPMS無關，只要該控制器帶有SPI總線接口，就可以接收、處理MC33594按順序發送來的數據。本設計中采用基于增強的AVR RISC結構的低功耗8位CMOS微控制器ATmega16，該控制器具有運行速度快、流水線方式執行指令、可在線編程、保密性高、價格低廉等特點。對于與主控制器相連的外圍器件其功能是當汽車的胎壓或溫度出現異常情況時，可通過聲、光和液晶顯示等形式向駕駛員告警。此外為了查詢、設置參數方便和便于通過計算機分析胎壓數據，該模塊還設計了鍵盤模塊和與計算機的串行通信接口。
4 汽車胎壓監測系統軟件設計
針對汽車胎壓監測系統的硬件設計，其軟件設計分為胎壓監測和中央接收兩部分。
4.1 胎壓監測模塊軟件設計
胎壓監測模塊的功能是準確、及時地監測各輪胎的內部氣壓、溫度數據并發送，其軟件流程圖如圖4所示。模塊上電后，首先控制器MC68HC908RF2對自身及傳感器MPXY8020A進行初始化。為了降低能耗，延長電池的使用壽命，控制器在沒有數據需要處理和傳輸的情況下，將自身配置成STOP模式，同時將傳感器配置成STANDBY模式，傳感器在此模式下其OUT引腳每3秒會喚醒(下降沿觸發)控制器響應鍵盤中斷。控制器在中斷處理程序中，通過修改傳感器的工作模式，分別讀取采集到的胎壓和溫度數據，然后啟動射頻發射模塊將數據以曼徹斯特編碼方式發送出去，同時進入省電模式，等待響應新的中斷。
4.2 中央接收模塊軟件設計
中央接收模塊軟件功能是完成數據的接收、處理、判別、顯示和告警，其流程如圖5所示。
該模塊以ATMEGA16為主控制器，在完成初始化后將自身配置為主機模式，通過SPI口對射頻接收器MC33594進行初始化，將其配置在315MHz FSK模式下工作，然后又將自己配置成從機模式，等待接收數據。MC33594在接收到從胎壓監測模塊發送來的壓力、溫度數據后，由SPI口傳送給控制器，控制器在接收數據的同時還要對該數據進行校驗和復雜的算法處理，并對處理后的結果進行判斷。若當前輪胎內部壓力、溫度超出了預先預定的范圍，則立即啟動聲光報警，通過蜂鳴器、發光二極管提示駕駛員當前存在異常，同時由LCD將發生異常的輪胎號、胎內信息顯示出來；否則提示汽車運行正常。此外，控制器還可以利用鍵盤設定、更新輪胎壓力、溫度上/下限值和輪胎ID號，利用串口實現與PC之間的通信，便于查詢、分析記錄的數據，為優化控制算法和分析交通事故提供依據。
目前，市場上的TPMS 產品主要分為兩種類型：一種是間接式TPMS，該類系統是通過汽車ABS系統的輪速傳感器來比較輪胎之間的轉速差別，以達到監測胎壓的目的；另一種是直接式TPMS，這種系統是利用安裝在每一個輪胎里的壓力傳感器來直接測量輪胎的氣壓、溫度，并對各輪胎氣壓、溫度進行監視，當輪胎氣壓太低或有滲漏時，系統會自動報警。本設計為直接式TPMS，實驗測試證明：該系統借助芯片組和軟件優化算法，能夠識別輪胎(包括備用胎)，檢測壓力過大或不足的情況，還能夠補償貨物重量的變化，監控輪胎溫度，對異常情況及時報警。此外，該系統還兼容各種汽車平臺和輪胎技術，模塊級的能量管理可以延長電池的使用壽命，并在電池電量過低時發出信號。
隨著人們對汽車主動安全性要求的提高及TPMS對防止重大交通事故發生的積極作用，市場對高性能的TPMS的需求量將會進一步增加。因此，汽車胎壓監測報警系統具有廣闊的發展空間和非常好的市場前景。
參考文獻
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