c - 使用 STM32F0 ADC 单独读取不同的输入

Question

STM32F072CBU 微 Controller 。

我有多个输入到 ADC 并且想单独读取它们。 STMcubeMX 生成样板代码，假设我希望按顺序读取所有输入，但我无法弄清楚如何更正此问题。

This blog post表达了我遇到的同样问题，但给出的解决方案似乎不起作用。为每次转换打开和关闭 ADC 与返回值中的错误相关。只有当我在 STMcubeMX 中配置单个 ADC 输入，然后在不取消初始化 ADC 的情况下进行轮询时，才能返回准确的读数。

cubeMX 的 adc_init 函数:

/* 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_SYNC_PCLK_DIV4;
  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 = DISABLE;
  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(__FILE__, __LINE__);
  }

    /**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_41CYCLES_5;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**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(__FILE__, __LINE__);
  }

    /**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(__FILE__, __LINE__);
  }

    /**Configure for the selected ADC regular channel to be converted. 
    */
  sConfig.Channel = ADC_CHANNEL_3;
  if (HAL_ADC_ConfigChannel(&hadc, &sConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**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(__FILE__, __LINE__);
  }

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

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

}

主.c

int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

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

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

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

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

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_ADC_Init();
  MX_USART1_UART_Init();

  /* USER CODE BEGIN 2 */
  //HAL_TIM_Base_Start_IT(&htim3);
  init_printf(NULL, putc_wrangler);
  HAL_ADCEx_Calibration_Start(&hadc);
  HAL_ADC_DeInit(&hadc); // ADC is initialized for every channel change
  schedule_initial_events();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  event_loop();
  /* USER CODE END WHILE */

  /* USER CODE BEGIN 3 */

  /* USER CODE END 3 */

}

我现在关闭 ADC 并重新初始化以更改 channel 的过程:

// Set up
  ADC_ChannelConfTypeDef channelConfig;

  channelConfig.SamplingTime = samplingT;
  channelConfig.Channel = sensorChannel;
  channelConfig.Rank = ADC_RANK_CHANNEL_NUMBER;

  if (HAL_ADC_Init(&hadc) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  if (HAL_ADC_ConfigChannel(&hadc, &channelConfig) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

// Convert
  uint16_t retval;

  if (HAL_ADC_Start(&hadc) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  if (HAL_ADC_PollForConversion(&hadc, 1) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  if (HAL_ADC_GetError(&hadc) != HAL_ADC_ERROR_NONE)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

  retval = (uint16_t) HAL_ADC_GetValue(&hadc);

  if (HAL_ADC_Stop(&hadc) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

// Close
  HAL_ADC_DeInit(&hadc);

在这一点上，我不太确定是否有办法实现我想要的，STM32 似乎死定了在常规组中的事件 ADC 线路并按顺序转换。

Answer 1

如果您想在单次转换模式下读取多个 ADC channel ，则必须在每次读取之前更改 channel 设置，但不必重新初始化 ADC。只需按照以下操作，选择新 channel (如果 channel 必须不同，您也可以更改采样时间，但通常可以相同)，选择 channel 等级，然后调用 HAL_ADC_ConfigChannel 函数。在此之后，您可以执行转换。

void config_ext_channel_ADC(uint32_t channel, boolean_t val)
{
  ADC_ChannelConfTypeDef sConfig;

  sConfig.Channel = channel;
  sConfig.SamplingTime = ADC_SAMPLETIME_71CYCLES_5;

  if(True == val)
  {
    sConfig.Rank = ADC_RANK_CHANNEL_NUMBER;
  }
  else
  {
    sConfig.Rank = ADC_RANK_NONE;
  }

  HAL_ADC_ConfigChannel(&hadc, &sConfig);
}

uint32_t r_single_ext_channel_ADC(uint32_t channel)
{
  uint32_t digital_result;

  config_ext_channel_ADC(channel, True);

  HAL_ADCEx_Calibration_Start(&hadc);

  HAL_ADC_Start(&hadc);
  HAL_ADC_PollForConversion(&hadc, 1000);
  digital_result = HAL_ADC_GetValue(&hadc);
  HAL_ADC_Stop(&hadc);

  config_ext_channel_ADC(channel, False);

  return digital_result;
}

用法示例:

#define SUPPLY_CURRENT  ADC_CHANNEL_5
#define BATTERY_VOLTAGE ADC_CHANNEL_6

uint16_t r_battery_voltage(uint16_t mcu_vcc)
{
  float vbat;
  uint16_t digital_val;

  digital_val = r_single_ext_channel_ADC(BATTERY_VOLTAGE);
  vbat = (mcu_vcc/4095.0) * digital_val;
  vbat = vbat * 2;         // 1/2 voltage divider

  return vbat;
}

uint16_t r_supply_current(uint16_t mcu_vcc)
{
  float v_sense, current;
  uint16_t digital_val;

  digital_val = r_single_ext_channel_ADC(SUPPLY_CURRENT);
  v_sense = (mcu_vcc/4095.0) * digital_val;
  current = v_sense * I_SENSE_GAIN;

  return current;
}

此代码用于 STM32F030。要读取内部温度传感器和引用电压，需要使用与上述函数略有不同的版本，因为必须设置额外的使能位。

void config_int_channel_ADC(uint32_t channel, boolean_t val)
{
  ADC_ChannelConfTypeDef sConfig;
  sConfig.Channel = channel;

  if(val == True)
  {
    if(channel == ADC_CHANNEL_VREFINT)
    {
      ADC->CCR |= ADC_CCR_VREFEN;
      hadc.Instance->CHSELR = (uint32_t)(ADC_CHSELR_CHSEL17);
    }
    else if(channel == ADC_CHANNEL_TEMPSENSOR)
    {
      ADC->CCR |= ADC_CCR_TSEN;
      hadc.Instance->CHSELR = (uint32_t)(ADC_CHSELR_CHSEL16);
    }

    sConfig.Rank          = ADC_RANK_CHANNEL_NUMBER;
    sConfig.SamplingTime  = ADC_SAMPLETIME_239CYCLES_5;
  }
  else if(val == False)
  {
    if(channel == ADC_CHANNEL_VREFINT)
    {
      ADC->CCR &= ~ADC_CCR_VREFEN;
      hadc.Instance->CHSELR = 0;
    }
    else if(channel == ADC_CHANNEL_TEMPSENSOR)
    {
      ADC->CCR &= ~ADC_CCR_TSEN;
      hadc.Instance->CHSELR = 0;
    }

    sConfig.Rank          = ADC_RANK_NONE;
    sConfig.SamplingTime  = ADC_SAMPLETIME_239CYCLES_5;
  }

  HAL_ADC_ConfigChannel(&hadc,&sConfig);
}

uint32_t r_single_int_channel_ADC(uint32_t channel)
{
  uint32_t digital_result;

  config_int_channel_ADC(channel, True);

  HAL_ADCEx_Calibration_Start(&hadc);

  HAL_ADC_Start(&hadc);
  HAL_ADC_PollForConversion(&hadc, 1000);
  digital_result = HAL_ADC_GetValue(&hadc);
  HAL_ADC_Stop(&hadc);

  config_int_channel_ADC(channel, False);

  return digital_result;
}

用于 MCU VDD 计算的内部引用电压使用示例:

#define VREFINT_CAL_ADDR   ((uint16_t*) ((uint32_t) 0x1FFFF7BA))

static float FACTORY_CALIB_VDD = 3.31;

uint16_t calculate_MCU_vcc()
{
  float analog_Vdd;
  uint16_t val_Vref_int = r_single_int_channel_ADC(ADC_CHANNEL_VREFINT);

  analog_Vdd = (FACTORY_CALIB_VDD * (*VREFINT_CAL_ADDR))/val_Vref_int;

  return analog_Vdd * 1000;
}

内部温度传感器读数:

#define TEMP30_CAL_ADDR  ((uint16_t*) ((uint32_t) 0x1FFFF7B8))
#define TEMP110_CAL_ADDR ((uint16_t*) ((uint32_t) 0x1FFFF7C2))

static float FACTORY_CALIB_VDD = 3.31;

float r_MCU_temp(uint16_t mcu_vcc)
{
  float temp;
  float slope = ((110.0 - 30.0)/((*TEMP110_CAL_ADDR) - (*TEMP30_CAL_ADDR)));

  uint16_t ts_data = r_single_int_channel_ADC(ADC_CHANNEL_TEMPSENSOR);

  temp = ((mcu_vcc/FACTORY_CALIB_VDD) * ts_data)/1000;
  temp = slope * (temp - (*TEMP30_CAL_ADDR)) + 30;

  return round_to(temp, 0);
}

请注意，您的 MCU 的校准数据地址可能不同，请查看数据表以获取更多信息。