关于ADC3的Calibration

只看该作者 · 2013-4-17 19:43

ADC1、ADC2、ADC3设置之后，进行Calibration：

  /* ADC1: Enable & Calibration */
  /* Enable ADC1 */
  ADC_Cmd(ADC1, ENABLE);

  /* Enable ADC1 reset calibration register */
  ADC_ResetCalibration(ADC1);
  /* Check the end of ADC1 reset calibration register */
  while(ADC_GetResetCalibrationStatus(ADC1));

  /* Start ADC1 calibration */
  ADC_StartCalibration(ADC1);
  /* Check the end of ADC1 calibration */
  while(ADC_GetCalibrationStatus(ADC1));

  /* ADC2: Enable & Calibration */
  /* Enable ADC2 */
  ADC_Cmd(ADC2, ENABLE);

  /* Enable ADC2 reset calibration register */
  ADC_ResetCalibration(ADC2);
  /* Check the end of ADC2 reset calibration register */
  while(ADC_GetResetCalibrationStatus(ADC2));

  /* Start ADC2 calibration */
  ADC_StartCalibration(ADC2);
  /* Check the end of ADC2 calibration */
  while(ADC_GetCalibrationStatus(ADC2));

  /* ADC3: Enable & Calibration */
  /* Enable ADC3 */
  ADC_Cmd(ADC3, ENABLE);

  /* Enable ADC3 reset calibration register */
  ADC_ResetCalibration(ADC3);
  /* Check the end of ADC3 reset calibration register */
  while(ADC_GetResetCalibrationStatus(ADC3));

  /* Start ADC3 calibration */
  ADC_StartCalibration(ADC3);
  /* Check the end of ADC3 calibration */
  while(ADC_GetCalibrationStatus(ADC3));

Run，然后就在  while(ADC_GetResetCalibrationStatus(ADC3));上死循环了。

查看stm32f10x_adc.c，找到ADC_ResetCalibration和ADC_GetResetCalibrationStatus：

void ADC_ResetCalibration(ADC_TypeDef* ADCx)
{
  /* Check the parameters */
  assert_param(IS_ADC_ALL_PERIPH(ADCx));
  /* Resets the selected ADC calibration registers */
  ADCx->CR2 |= CR2_RSTCAL_Set;
}

FlagStatus ADC_GetResetCalibrationStatus(ADC_TypeDef* ADCx)
{
  FlagStatus bitstatus = RESET;
  /* Check the parameters */
  assert_param(IS_ADC_ALL_PERIPH(ADCx));
  /* Check the status of RSTCAL bit */
  if ((ADCx->CR2 & CR2_RSTCAL_Set) != (uint32_t)RESET)
  {
/* RSTCAL bit is set */
bitstatus = SET;
  }
  else
  {
/* RSTCAL bit is reset */
bitstatus = RESET;
  }
  /* Return the RSTCAL bit status */
  return  bitstatus;
}

用Watchwindow查看，发现：
ADC1的CR2末四位：0011，其中RSTCAL为0；
ADC2的CR2末四位：0011，其中RSTCAL为0；
ADC3的CR2末四位：1011，其中RSTCAL为1.

Reference manual关于RSTCAL位的说明如下：This bit is set by software and cleared by hardware. It is cleared after the calibration registers are initialized.
就是说ADC3的Calibration功能在“ADCx->CR2 |= CR2_RSTCAL_Set;”之后没有“cleared by hardware”。

然而，ADC1、ADC2均没有出现这个问题，实在感到不解。本人初学，望各位大侠指导一下。