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关于stm32 APB总线上的”接口时钟使能”与”外设时钟使能” | 重归混沌的BLOG

关于stm32 APB总线上的”接口时钟使能”与”外设时钟使能”

作者

今天看<<例说stm32>>上的RTC时钟,发现他没有使能APB1的上BKP时钟,就能读出BKP寄存器里的内容.很是不解,又看了一遍发现APB总线上的时钟使能分为两种,一种是时接口时钟一种是外设时钟.
又仔细观查了一下时钟树发现在APB外设时钟使能寄存器上表现为接口时钟的都已经有了自己的时钟,再经实验证明所有这种不需要在APB上使能就有自已时钟的外设(即在APBxENR的某一位上代表的是这个外设的接口时钟的外设)在不需要使能接口时钟的情况下就能读出这种外设的寄存器的内容!

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