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我正在使用 STM32F0 微控制器的 ADC 通道（12 位分辨率）来读取电路板三个不同点的电压值。我要做的是每2秒读取一次值（我有2秒的时间读取三个点的值）并通过UART接口发送。为了选择我正在读取的 ADC 通道，我正在实现电压读取功能，如下所示：

uint16_t readv1(void){
    //Here I try to read ADC_CHANNEL_1
    //chConfig and txtbuff are global variables:
    //ADC_ChannelConfTypeDef chConfig;
    //char txtbuff[64];

    chConfig.Channel = ADC_CHANNEL_1;
    HAL_ADC_ConfigChannel(&hadc, &chConfig);
    uint32_t vref = HAL_ADC_GetValue(&hadc);
    uint16_t vref2 = (uint16_t) vref;
    sprintf(TextBuffer, "%u\n", vref2);
    HAL_UART_Transmit(&huart4, (uint8_t*)txtbuff, strlen(txtbuff), 0xFFFFFFFF);

    return vref2;
}

这是扫描一个 ADC 通道的功能。为了读取其他两个 ADC 通道，我使用相同的程序，只需更改通道号所在n行中的值。注意在函数中声明的类型相同，但是是全局变量，是否应该在每个函数中声明为局部变量？chConfig.Channel = ADC_CHANNEL_n;nchConfigsConfigMX_ADC_Init()chConfig

我遇到的问题是该readv1函数读取一个恒定电压（我已经用电压表检查过），但是通过 UART 显示在终端中的数字变化很大，在 120 到 2400 之间。我不确定是否使用该线chConfig.Channel = ADC_CHANNEL_1;来选择频道很好，或者是否有任何其他程序要遵循。我怎样才能正确读取每个 ADC 的值？

为了每两秒扫描一次 ADC，我使用了一个 8 MHz 定时器，如下所示：

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim){
    if (htim->Instance==TIM3){
        //Here I call the functions which read the voltage values of different ADC channels
        volt1 = readv1();
        readv2(volt1);
        readv3(volt1);
    }
}

这是我初始化外围设备的主要功能：

int main(void)
{

  /* MCU Configuration----------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* Configure the system clock */
  SystemClock_Config();

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USART4_UART_Init();
  MX_ADC_Init();
  MX_TIM3_Init();

  /* USER CODE BEGIN 2 */
  HAL_ADC_Start_IT(&hadc);
  HAL_TIM_Base_Start_IT(&htim3);
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {

  }
}

以下是定时器和 ADC 的初始化函数：

/* TIM3 init function */
static void MX_TIM3_Init(void)
{

  TIM_ClockConfigTypeDef sClockSourceConfig;
  TIM_MasterConfigTypeDef sMasterConfig;

  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 8000;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 1999;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
  {
    Error_Handler();
  }

  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }

}


/* ADC init function */
static void MX_ADC_Init(void)
{

  ADC_ChannelConfTypeDef sConfig;

    /**Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion) 
    */
  hadc.Instance = ADC1;
  hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
  hadc.Init.Resolution = ADC_RESOLUTION_12B;
  hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;
  hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  hadc.Init.LowPowerAutoWait = DISABLE;
  hadc.Init.LowPowerAutoPowerOff = DISABLE;
  hadc.Init.ContinuousConvMode = ENABLE;
  hadc.Init.DiscontinuousConvMode = DISABLE;
  hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
  hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc.Init.DMAContinuousRequests = DISABLE;
  hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
  if (HAL_ADC_Init(&hadc) != HAL_OK)
  {
    Error_Handler();
  }

    /**Configure for the selected ADC regular channel to be converted. 
    */
  sConfig.Channel = ADC_CHANNEL_0;
  sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
  sConfig.SamplingTime = ADC_SAMPLETIME_239CYCLES_5;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

    /**Configure for the selected ADC regular channel to be converted. 
    */
  sConfig.Channel = ADC_CHANNEL_1;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

    /**Configure for the selected ADC regular channel to be converted. 
    */
  sConfig.Channel = ADC_CHANNEL_2;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

    /**Configure for the selected ADC regular channel to be converted. 
    */
  sConfig.Channel = ADC_CHANNEL_4;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    Error_Handler();
  }

}
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1 回答 1

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我通过如下修改函数解决了这个问题：

uint16_t readv1(void){
    chConfig.Channel = ADC_CHANNEL_1;

    // I added these two lines after the ADC channel selection
    chConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
    chConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
    // The first one will configure the ADC channel as enabled
    // The second one is the sampling time (1.5)

    HAL_ADC_ConfigChannel(&hadc, &chConfig);

    // Then I added these two instructions:
    HAL_ADC_Start_IT(&hadc);
    HAL_ADCEx_Calibration_Start(&hadc);
    // The first one starts the ADC in interruption mode
    // The second one calls the calibration function

    uint32_t vref = HAL_ADC_GetValue(&hadc);

    // Finally I added these three last instructions:
    HAL_ADC_Stop_IT(&hadc);
    chConfig.Rank = ADC_RANK_NONE;
    HAL_ADC_ConfigChannel(&hadc, &chConfig);
    // The first one stops the ADC
    // The second one will configure the ADC channel as disabled
    // The third one sets the channel with the new parameters

    uint16_t vref2 = (uint16_t) vref;
    sprintf(TextBuffer, "%u\n", vref2);
    HAL_UART_Transmit(&huart4, (uint8_t*)txtbuff, strlen(txtbuff), 0xFFFFFFFF);    

    return vref2;
}

我添加了我在读取 ADC 通道的三个函数中提到的行。实际上，当我使用相同的程序读取所有 ADC 通道时，我创建了一个函数，该函数接收通道号作为参数。

于 2017-04-22T09:44:47.073 回答