新手学习用STM32, ADC问题请教

只看该作者 · 2008-11-1 10:01

STM32F101运行正常 (PB0~PB8 I/O能输入输出,vREF+=3.3v, VREF-=0V), 想编程对PC1端口的模拟输入进行读取 (万用表量得端口的输入电压为1.2V),程序如下所示,但读到的DataValue值总是0x0000;
大侠们帮忙看看问题出在那。

......
u16 DataValue;
......
/* Configure PC.01 (ADC Channel11) as analog input -------------------------*/
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

/* ADC1 configuration ------------------------------------------------------*/
  ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 1;
  ADC_Init(ADC1, &ADC_InitStructure);

/* ADC1 regular channel1 configuration */
  ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_55Cycles5);

/* Enable ADC1 */
  ADC_Cmd(ADC1, ENABLE);

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

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

/* Start ADC1 Software Conversion */
  ADC_SoftwareStartConvCmd(ADC1, ENABLE);

DataValue = ADC_GetConversionValue(ADC1);