STM32 TIMER2的使用

配置定时100us的配置如下：

1. TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;  

2. RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);  

3. TIM_DeInit(TIM2);  

4. TIM_TimeBaseStructure.TIM_Period = 1;//59999;//1199;//9999;  

5. TIM_TimeBaseStructure.TIM_CounterMode =  TIM_CounterMode_Up;  

6. TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;  

7. TIM_TimeBaseStructure.TIM_Prescaler=3499;//分频35999  

8. TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);  

9. TIM_ClearFlag(TIM2,TIM_IT_Update);  

10. TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);  

11. TIM_Cmd(TIM2, DISABLE);  

//((1+TIM_Prescaler )/f_soc)*(1+TIM_Period )=((1+7199)/72M)*(1+9999)=1秒

time = ((1+3499)/72M)*(1+1) =100us ：f_soc =72MHz

看STM32的时钟树可以知道 Timer的f_soc= APB1_Clk * APB1_Prescaler

APB1_Clk = AHB_Clk /APB1_Prescaler

AHB_CLk = Sysclk /AHB_Prescaler

我这里的时钟设置 Sysclk = 72MHz

AHB_Prescaler = 1 => AHB_Clk = 72MHz

因为 APB1_CLK_max = 36MHz

所以  APB1_Prescaler =2

于是 Timer2 的f_soc = 72MHz