STM8S103的LSI频率测量问题

只看该作者 · 2015-11-9 23:08

本人想用STM8S103的AWU功能，看了ST库函数的例程也模仿着写了一段LSI频率的测试代码，代码如下：
//**********************************************************
//LSI频率测量函数*******************************************
uint32_t LSIMeasurment(void)
{

  uint32_t lsi_freq_hz = 0;
  uint32_t fmaster = 0;
  unint ICValue1 = 0;
  unint ICValue2 = 0;
unchar tmpccr1h = 0;
unchar tmpccr1l = 0;

  /* Get master frequency */
  fmaster = 16000000U;//16MHZ
  /* Enable the LSI measurement: LSI clock connected to timer Input Capture 1 */
  AWU_CSR |= 0x01;//AWU_CSR_MSR;

  /* Measure the LSI frequency with TIMER Input Capture 1 */
  /* Capture only every 8 events!!! */
  /* Enable capture of TI1 */

  TIM1_CCER1 &= 0xFE;//bit0=0,禁止捕抓才能对TIM1_CCMR1的(CC1S位操作)
  TIM1_CCMR1 = 0xFD; // TIM1设为捕抓输入模式,IC1映射到TI1上,每8件事触发一次。
  TIM1_CCER1 &= 0xFD;//
  TIM1_CCER1 |= 0x01;//使能捕抓
  /* Enable TIM1 */
TIM1_CR1 |= 0x01;  //启动计数器//TIM1_Cmd(ENABLE);

  /* wait a capture on cc1 */
  while((TIM1_SR1 & 0x02) != 0x02) ;
  /* Get CCR1 value*/
  //ICValue1 = TIM1_GetCapture1();
tmpccr1h = TIM1_CCR1H;
tmpccr1l = TIM1_CCR1L;
ICValue1 = (unint) tmpccr1l;
ICValue1 |= (unint)((unint)tmpccr1h << 8);

  TIM1_SR1 &= 0xFD;//CC1IF位清0//TIM1_ClearFlag(TIM1_FLAG_CC1);

  /* wait a capture on cc1 */
  while((TIM1_SR1 & 0x02) != 0x02);
  /* Get CCR1 value*/
  //ICValue2 = TIM1_GetCapture1();
tmpccr1h = TIM1_CCR1H;
tmpccr1l = TIM1_CCR1L;
ICValue1 = (unint) tmpccr1l;
ICValue1 |= (unint)((unint)tmpccr1h << 8);

  TIM1_SR1 &= 0xFD;//CC1IF位清0//TIM1_ClearFlag(TIM1_FLAG_CC1);

  /* Disable IC1 input capture */
  TIM1_CCER1 &= 0XFE;//(uint8_t)(~TIM1_CCER1_CC1E);
  /* Disable timer2 */
  //TIM1_Cmd(DISABLE);
  TIM1_CR1 &= 0xFE;  //停止计数器//TIM1_Cmd(DISABLE);
  /* Compute LSI clock frequency */
  lsi_freq_hz = (8 * fmaster) / (ICValue2 - ICValue1);

  /* Disable the LSI measurement: LSI clock disconnected from timer Input Capture 1 */
  AWU_CSR &= 0xFE;

return (lsi_freq_hz);
}

现在的问题是一直没能正确测量LSI死循环在“  while((TIM1_SR1 & 0x02) != 0x02) ;”这里了，LSI频率已经打开了的。
请大家帮忙分析分析问题所在，谢谢！