Timer1复位触发器代码错误

当使用tiM1测量信号的频率时，我发现了一些非常有趣/奇怪的东西：


将TIM2和TIM1设置为使用相同的预分频器（例如8）。 TIM2配置为生成周期为10000的PWM，在这种情况下产生2Mhz /（8 * 10000）= 25Hz信号。

然后，TIM1配置为输入CapCom模式，其触发控制器在输入通道1的每个上升沿复位定时器。
现在将引脚TIM2_Chan1与TIM1_Chan1连接。理论上，在TIM1的CapCompareReg1中获得的值应该完全等于TIM2的周期。

在这个例子中，CCR1包含8880而不是9999.当为TIM1采用较小的预分频器时，这些值的偏差更加严重。
：
TIM1_DeInit（）;

/ *将TIM1频率设置为1 Mhz（= 2Mhz / 2），因此1个单位= 1us * /
TIM1_TimeBaseInit（8，TIM1_COUNTERMODE_UP，60000,0）; //溢出前最多60000步

/ * TIM1通道1用于（PC1）上升沿，没有分频器（1）和滤波器（0）* /

TIM1_ICInit（TIM1_CHANNEL_1，TIM1_ICPOLARITY_RISING，TIM1_ICSELECTION_DIRECTTI，TIM1_ICPSC_DIV1,0x00）;

/ *用于同步​​计数器的触发输入（TRGI）* /
TIM1_SelectInputTrigger（TIM1_TS_TI1FP1）;
/ *复位模式 - 所选触发信号的上升沿（本例中为TI1FP1）重新初始化计数器和
生成寄存器的更新。 * /
TIM1_SelectSlaveMode（TIM1_SLAVEMODE_RESET）;
/ *溢出中断;启用Capture1中断* /
TIM1_ITConfig（TIM1_IT_UPDATE | TIM1_IT_CC1，ENABLE）;
/ *生成更新事件* /
TIM1_GenerateEvent（TIM1_EVENTSOURCE_UPDATE）;
/ *清除CC1并更新标志* /
TIM1_ClearFlag（TIM1_FLAG_CC1 | TIM1_FLAG_UPDATE）;
//更新URS位van TIM_CR1，只有上溢/下溢才会产生中断。
TIM1_UpdateRequestConfig（TIM1_UPDATESOURCE_REGULAR）;
/ *启用TIM1 * /
TIM1_Cmd（ENABLE）;
TIM1_GenerateEvent（TIM1_EVENTSOURCE_UPDATE）;

// ---------------------------
TIM2_TimeBaseInit（TIM2_PRESCALER_8,9999）;
/ * PWM1模式配置：Channel1 * /
TIM2_OC1Init（TIM2_OCMODE_PWM1，TIM2_OUTPUTSTATE_ENABLE，4000，TIM2_OCPOLARITY_HIGH）;
TIM2_OC1PreloadConfig（ENABLE）;
TIM2_ARRPreloadConfig（ENABLE）;
/ * TIM2启用计数器* /
TIM2_Cmd（ENABLE）;
// ---------------------------


/ *启用常规中断* /
enableInterrupts（）;


void TIM1_CAP_COM_IRQHandler（void）中断12

{
measuredTime =（TIM1_GetCapture1（））;
TIM1_ClearFlag（TIM1_FLAG_CC1）; //清除捕获比较标志
}


因此，计时器必须在某处丢失“计数”。具有讽刺意味的是，使用EXTI中断完成整个操作并在软件中启动/停止计数器更为准确。

我很想相信我的代码是错误的，但是我明白了while定时器同步实现可能是一个废话。

＃破碎定时器STM8S



以下为原文




I found something very funny/weird when using TIM1 to measure the frequency of a signal:


Set TIM2 and TIM1 to use the same prescaler (e.g. 8). TIM2 is configured to generate PWM with period 10000, in this case resulting in 2Mhz/(8*10000)=25Hz signal.

Then, TIM1 is configured in Input CapCom mode, and its trigger controller resets the timer on every rising edge on input channel1.
Now connect pins TIM2_Chan1 with TIM1_Chan1. In theory, the values obtained in CapCompareReg1 of TIM1 should equal the period of TIM2 perfectly.

In this example, the CCR1 contains 8880 instead of 9999. The values deviate even more worse when taking smaller prescalers for TIM1.





:
    TIM1_DeInit();

     /* Set TIM1 Frequency to 1 Mhz (=2Mhz/2), thus 1 unit = 1us */
   TIM1_TimeBaseInit(8, TIM1_COUNTERMODE_UP, 60000, 0);//Max 60000 steps before overflow
      
  /* TIM1 channel 1 is used (PC1) with rising edge and no divider (1) nor filter (0) */

   TIM1_ICInit(TIM1_CHANNEL_1, TIM1_ICPOLARITY_RISING, TIM1_ICSELECTION_DIRECTTI,  TIM1_ICPSC_DIV1, 0x00);     
  
   /* the trigger input (TRGI) to used to synchronize the counter */
     TIM1_SelectInputTrigger(TIM1_TS_TI1FP1);
   /* Reset mode - Rising edge of the selected trigger signal (TI1FP1 in this case) re-initializes the counter and
      generates an update of the registers. */
   TIM1_SelectSlaveMode(TIM1_SLAVEMODE_RESET);
   /* Overflow interrupt ; Capture1 interrupt enabled */
   TIM1_ITConfig(TIM1_IT_UPDATE | TIM1_IT_CC1, ENABLE);
   /* Generate an update event */
   TIM1_GenerateEvent(TIM1_EVENTSOURCE_UPDATE);
   /* Clear CC1 and update Flag */
   TIM1_ClearFlag(TIM1_FLAG_CC1 | TIM1_FLAG_UPDATE);
     //Update URS bit van TIM_CR1 so only over/underflow generates interrupt.
     TIM1_UpdateRequestConfig(TIM1_UPDATESOURCE_REGULAR);
     /* Enable TIM1 */
   TIM1_Cmd(ENABLE);
     TIM1_GenerateEvent(TIM1_EVENTSOURCE_UPDATE);
  
     //---------------------------
     TIM2_TimeBaseInit(TIM2_PRESCALER_8, 9999);
     /* PWM1 Mode configuration: Channel1 */  
     TIM2_OC1Init(TIM2_OCMODE_PWM1, TIM2_OUTPUTSTATE_ENABLE, 4000, TIM2_OCPOLARITY_HIGH);
     TIM2_OC1PreloadConfig(ENABLE);
     TIM2_ARRPreloadConfig(ENABLE);
     /* TIM2 enable counter */
     TIM2_Cmd(ENABLE);
     //---------------------------
  
  
   /* Enable general interrupts */
   enableInterrupts();




void TIM1_CAP_COM_IRQHandler(void) interrupt 12

{
     measuredTime = (TIM1_GetCapture1());
     TIM1_ClearFlag(TIM1_FLAG_CC1);//Clear capture-compare flag
}
  
  
So, the timer must lose ''counts'' somewhere. Ironically, it is more accurate to do the whole thing with EXTI interrupts and start/stop the counter in software.

I would love to believe that my code is wrong, but it dawns on me that the while timer synchronisation implementation could be a piece of crap.
  
#broken-timer-stm8s