预分频器问题

只看该作者 · 2014-4-10 20:04

TIM4的预分频器的值是怎么获得的，它也包含预装载寄存器和影子寄存器，写入的预分频值先写入与装载寄存器，然后在事件更新时，预装载寄存器的值才传入影子寄存器，ARR中是这样的，那PRESCALER这里也是这样吗？手册中这样写的：The prescaler value is loaded through a preload register. The shadow register, which
contains the current value to be used, is loaded as soon as the LS byte has been written. 怎么是低八字节写入后就立即传入到影子寄存器了？