Keil MDK STM32系列

配置 ADC

模式: 如果只启用了一个ADC, 这里只能配置为Independent mode
时钟分频: 这个选项是ADC的预分频器, 可设置为2/4/6/8, 决定了一个ADC时钟周期. 加入设置为2, 由于ADC是挂载在APB2总线(84M)上, 所以一个ADC时钟便是84 * M/2=42M
分辨率: 最高为12位分辨率, 分辨率越高转换时间越长
数据对齐方式: 如果选择12位分辨率, 右对齐, 得到的结果最大便是4096.
扫描模式: 转换完一个通道会不会继续转换下一个通道
连续转换模式: 使能的话转换将连续进行
不连续转换模式: 当使能多个转换通道时, 可单独设置不连续转换通道.
DMA连续请求: 是否连续请求DMA.
EOC标志设置: 当有多个转换通道时, 是每转换完一个通道设置一次EOC标志还是所有通道都转换完设置一次EOC标志.
转换的通道数:
触发模式: 可选择软件触发, 外部触发或定时器事件触发
秩序列表: 设置转换周期数和转换顺序
注入通道设置
窗口看门狗模式

配置 ADC 为主动请求模式

while (1)

{

  /*##-1- Start the conversion process #######################################*/

  HAL_ADC_Start(&hadc1);

  /*##-2- Wait for the end of conversion #####################################*/

   /*  Before starting a new conversion, you need to check the current state of

              the peripheral; if it’s busy you need to wait for the end of current

              conversion before starting a new one.

              For simplicity reasons, this example is just waiting till the end of the

              conversion, but application may perform other tasks while conversion

              operation is ongoing. */

  HAL_ADC_PollForConversion(&hadc1, 50);

  /* Check if the continous conversion of regular channel is finished */

  if(HAL_IS_BIT_SET(HAL_ADC_GetState(&hadc1), HAL_ADC_STATE_REG_EOC))

  {

      /*##-3- Get the converted value of regular channel  ######################*/

      AD_Value = HAL_ADC_GetValue(&hadc1);

      printf("MCU Temperature : %.1f¡æ\r\n",((AD_Value*3300/4096-760)/2.5+25));

  }

  HAL_Delay(1000);

}

配置 ADC 为多通道连续扫描DMA模式

开ADC的IN0/IN1两个通道
- 在Pinout图上, 将PA0和PA1设为ADC1_IN0和ADC2_IN1
配置时钟
ADC1相关配置
ADCs_Common_Settings
- Mode: Independent mode
ADC_Settings
- Clock Prescaler: PCLK2 divided by 4 可以在时钟配置页看到PCLK2的值
- Resolution: 12bits (15 ADC Clock cycles) 采样精度12bit, 此时每次采样需要15个时钟周期, 8bit对应11个时钟周期
- Data Alignment: Right alignment
- Scan Conversion Mode: Enabled
- Continuous Conversion Mode: Enabled --> for DMA
- Discontinuous Conversion Mode: Disabled
- DMA Continuous Requests: Enabled
- End Of Conversion Selection: EOC flag at the end of single channel conversion
ADC_Regular_ConversionMode
- Number of Conversion: 2 --> 2 channels
- External Trigger Conversion Source: Regular Conversion launched by software
- External Trigger Conversion Edge: None
- Rank: 1: Choose channel 0
- Rank: 2: Choose channel 1
ADC_Injected_ConversionMode
- Number of Conversions: 0
DMA相关配置
ADC1
- Stream: DMA2 Stream 4
- Direction: Peripheral To Memory
- Priority: High
DMA Request Settings
- Mode: Circular
- Increment Address: Memory
- Datawidth: Peripheral->Half Word, Memory->Half Word
NVIC Settings
- ADC1 global interrupt: Enabled unchecked
- DMA2 stream4 global interrupt: Enabled checked

ADC+DMA配置, 体现在代码上的变化

stm32f4xx_hal_conf.h 去掉了ADC的注释

#define HAL_ADC_MODULE_ENABLED

stm32f4xx_it.h 增加了方法声明

void DMA2_Stream4_IRQHandler(void);

stm32f4xx_it.c 增加了对应的typeDef和方法定义

extern DMA_HandleTypeDef hdma_adc1;

void DMA2_Stream4_IRQHandler(void)

{

  HAL_DMA_IRQHandler(&hdma_adc1);

}

stm32f4xx_hal_msp.c

extern DMA_HandleTypeDef hdma_adc1;

void HAL_ADC_MspInit(ADC_HandleTypeDef* hadc)

{

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  if(hadc->Instance==ADC1)

  {

    __HAL_RCC_ADC1_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();

    /**ADC1 GPIO Configuration

    PA0-WKUP     ------> ADC1_IN0

    PA1     ------> ADC1_IN1

    */

    GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;

    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;

    GPIO_InitStruct.Pull = GPIO_NOPULL;

    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

    /* ADC1 DMA Init */

    /* ADC1 Init */

    hdma_adc1.Instance = DMA2_Stream4;

    hdma_adc1.Init.Channel = DMA_CHANNEL_0;

    hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;

    hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;

    hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;

    hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;

    hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;

    hdma_adc1.Init.Mode = DMA_CIRCULAR;

    hdma_adc1.Init.Priority = DMA_PRIORITY_HIGH;

    hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_DISABLE;

    if (HAL_DMA_Init(&hdma_adc1) != HAL_OK)

    {

      Error_Handler();

    }

    __HAL_LINKDMA(hadc,DMA_Handle,hdma_adc1);

  }

}

void HAL_ADC_MspDeInit(ADC_HandleTypeDef* hadc)

{

  if(hadc->Instance==ADC1)

  {

    /* Peripheral clock disable */

    __HAL_RCC_ADC1_CLK_DISABLE();

    /**ADC1 GPIO Configuration

    PA0-WKUP     ------> ADC1_IN0

    PA1     ------> ADC1_IN1

    */

    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_0|GPIO_PIN_1);

    /* ADC1 DMA DeInit */

    HAL_DMA_DeInit(hadc->DMA_Handle);

  }

}

main.c

ADC_HandleTypeDef hadc1;

DMA_HandleTypeDef hdma_adc1;

static void MX_ADC1_Init(void)

{

  ADC_ChannelConfTypeDef sConfig = {0};

  hadc1.Instance = ADC1;

  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;

  hadc1.Init.Resolution = ADC_RESOLUTION_12B;

  hadc1.Init.ScanConvMode = ENABLE;

  hadc1.Init.ContinuousConvMode = ENABLE;

  hadc1.Init.DiscontinuousConvMode = DISABLE;

  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;

  hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;

  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;

  hadc1.Init.NbrOfConversion = 2;

  hadc1.Init.DMAContinuousRequests = ENABLE;

  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;

  if (HAL_ADC_Init(&hadc1) != HAL_OK)

  {

    Error_Handler();

  }

  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.

  */

  sConfig.Channel = ADC_CHANNEL_0;

  sConfig.Rank = 1;

  sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;

  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

  {

    Error_Handler();

  }

  /** Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.

  */

  sConfig.Channel = ADC_CHANNEL_1;

  sConfig.Rank = 2;

  if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)

  {

    Error_Handler();

  }

}

/**

  * Enable DMA controller clock

  */

static void MX_DMA_Init(void)

{

  __HAL_RCC_DMA2_CLK_ENABLE();

  HAL_NVIC_SetPriority(DMA2_Stream4_IRQn, 0, 0);

  HAL_NVIC_EnableIRQ(DMA2_Stream4_IRQn);

}

最后, 在main.c中增加用于存储DMA数据的数组, 将数组地址传给HAL_ADC_Start_DMA()开启DMA传输就可以得到数据了.

DMA数组大小和中断的问题

数组的大小与HAL_ADC_Start_DMA()方法第三个参数length一致, 这里length代表的是数据的个数. 在设置这个大小时, 如果开启了DMAx_Streamx_IRQn的中断, 要考虑sConfig.SamplingTime指定的采样时间不能太短, 太短的话会一直卡在中断里(因为中断什么都不做也需要时间). 这个与SYSCLK大小无关, 在两个通道采样时

如果这里指定的值为ADC_SAMPLETIME_3CYCLES, 这个数组大小至少为6, 如果等于4采样循环会卡住
如果指定的值为ADC_SAMPLETIME_15CYCLES, 这个数组大小至少为4
如果指定的值为ADC_SAMPLETIME_28CYCLES, 数组大小可以为2

如果不需要使用DMA中断, 可以在 MX_DMA_Init()方法中, 将HAL_NVIC_EnableIRQ(DMA2_Stream4_IRQn);这句注释掉或者改成HAL_NVIC_DisableIRQ(DMA2_Stream4_IRQn);指定禁用它, 这个数组就可以设到最小(和采样通道数一致)了.

uint16_t ADC_Value[6];

main(void) {

   HAL_ADC_Start_DMA(&hadc1,(uint32_t*)&ADC_Value, 6);    // Enable DMA transfer

   while (1)

  {

    printf("%d %d %d %d\r\n",

      ADC_Value[0], ADC_Value[1], ADC_Value[2], ADC_Value[3]);

    HAL_Delay(100);

  }

}

DMA中断处理回调

查看代码可以看到, 在stm32f4xxx_hal_dma.h中, 定义的 DMA_HandleTypeDef 类型中, 包含了几个对应中断的处理方法

typedef struct __DMA_HandleTypeDef

{

  DMA_Stream_TypeDef         *Instance;                                                        /*!< Register base address                  */

  DMA_InitTypeDef            Init;                                                             /*!< DMA communication parameters           */

  HAL_LockTypeDef            Lock;                                                             /*!< DMA locking object                     */

  __IO HAL_DMA_StateTypeDef  State;                                                            /*!< DMA transfer state                     */

  void                       *Parent;                                                          /*!< Parent object state                    */

  void                       (* XferCpltCallback)( struct __DMA_HandleTypeDef * hdma);         /*!< DMA transfer complete callback         */

  void                       (* XferHalfCpltCallback)( struct __DMA_HandleTypeDef * hdma);     /*!< DMA Half transfer complete callback    */

  void                       (* XferM1CpltCallback)( struct __DMA_HandleTypeDef * hdma);       /*!< DMA transfer complete Memory1 callback */

  void                       (* XferM1HalfCpltCallback)( struct __DMA_HandleTypeDef * hdma);   /*!< DMA transfer Half complete Memory1 callback */

  void                       (* XferErrorCallback)( struct __DMA_HandleTypeDef * hdma);        /*!< DMA transfer error callback            */

  void                       (* XferAbortCallback)( struct __DMA_HandleTypeDef * hdma);        /*!< DMA transfer Abort callback            */

  __IO uint32_t              ErrorCode;                                                        /*!< DMA Error code                          */

  uint32_t                   StreamBaseAddress;                                                /*!< DMA Stream Base Address                */

  uint32_t                   StreamIndex;                                                      /*!< DMA Stream Index                       */

}DMA_HandleTypeDef;

其中处理接收完成的方法是 XferCpltCallback , 这个在 stm32f4xx_hal_adc.c 中, 被指定为相应的静态方法

stm32f4xx_hal_adc.c

HAL_StatusTypeDef HAL_ADC_Start_DMA(ADC_HandleTypeDef* hadc, uint32_t* pData, uint32_t Length)

{

  //...

  /* Set the DMA transfer complete callback */

  hadc->DMA_Handle->XferCpltCallback = ADC_DMAConvCplt;

对应不同外设, 指定的方法是不同的, 例如对于uart, stm32f4xx_hal_uart.c中指定的是

HAL_StatusTypeDef HAL_UART_Transmit_DMA(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)

{

  //...

  /* Set the UART DMA transfer complete callback */

  huart->hdmatx->XferCpltCallback = UART_DMATransmitCplt;

对于ADC, 再进一步在ADC_DMAConvCplt()方法中定义了处理方法

static void ADC_DMAConvCplt(DMA_HandleTypeDef *hdma)

{

  //...

    /* Conversion complete callback */

#if (USE_HAL_ADC_REGISTER_CALLBACKS == 1)

    hadc->ConvCpltCallback(hadc);

#else

    HAL_ADC_ConvCpltCallback(hadc);

#endif /* USE_HAL_ADC_REGISTER_CALLBACKS */

  }

  else /* DMA and-or internal error occurred */

  {

    if ((hadc->State & HAL_ADC_STATE_ERROR_INTERNAL) != 0UL)

    {

      /* Call HAL ADC Error Callback function */

#if (USE_HAL_ADC_REGISTER_CALLBACKS == 1)

      hadc->ErrorCallback(hadc);

#else

      HAL_ADC_ErrorCallback(hadc);

#endif /* USE_HAL_ADC_REGISTER_CALLBACKS */

    }

  else

  {

      /* Call DMA error callback */

      hadc->DMA_Handle->XferErrorCallback(hdma);

    }

  }

}

所以, 开发时只需要定义 HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc) 和 HAL_ADC_ErrorCallback(ADC_HandleTypeDef* hadc)方法, 就能处理DMA传输完成的中断

参考

https://blog.csdn.net/weixin_42157650/article/details/88913871
仅用2个字节做buffer的ADC https://controllerstech.blogspot.com/2017/08/adc-using-dma.html
禁用DMA中断 https://shequ.stmicroelectronics.cn/forum.php?mod=viewthread&tid=615792