如何通过HAL库函数使用ADC？

1万 · 2015-11-12 18:16

  * @file stm32f4xx_hal_adc.c

==============================================================================
                  ##### ADC Peripheral features #####
  ==============================================================================
  [..]
  (#) 12-bit, 10-bit, 8-bit or 6-bit configurable resolution.
  (#) Interrupt generation at the end of conversion, end of injected conversion,
   and in case of analog watchdog or overrun events
  (#) Single and continuous conversion modes.
  (#) Scan mode for automatic conversion of channel 0 to channel x.
  (#) Data alignment with in-built data coherency.
  (#) Channel-wise programmable sampling time.
  (#) External trigger option with configurable polarity for both regular and
   injected conversion.
  (#) Dual/Triple mode (on devices with 2 ADCs or more).
  (#) Configurable DMA data storage in Dual/Triple ADC mode.
  (#) Configurable delay between conversions in Dual/Triple interleaved mode.
  (#) ADC conversion type (refer to the datasheets).
  (#) ADC supply requirements: 2.4 V to 3.6 V at full speed and down to 1.8 V at
   slower speed.
  (#) ADC input range: VREF(minus) = VIN = VREF(plus).
  (#) DMA request generation during regular channel conversion.

-------------------------------------------------------------------------------------------
上面这些ADC外设特性说明，介绍了STM32F4的ADC特点，学习时候也是很重要的。

1万 · 2015-11-12 19:00

                  ##### How to use this driver #####
  ==============================================================================
怎样使用这些驱动呢？
(#)Initialize the ADC low level resources by implementing the HAL_ADC_MspInit():                         初始化ADC底层资源，通过HAL——ADC_MspInit()
   (##) Enable the ADC interface clock using __HAL_RCC_ADC_CLK_ENABLE()
   (##) ADC pins configuration
         (+++) Enable the clock for the ADC GPIOs using the following function:
               __HAL_RCC_GPIOx_CLK_ENABLE()
         (+++) Configure these ADC pins in analog mode using HAL_GPIO_Init()
   (##) In case of using interrupts (e.g. HAL_ADC_Start_IT())
         (+++) Configure the ADC interrupt priority using HAL_NVIC_SetPriority()
         (+++) Enable the ADC IRQ handler using HAL_NVIC_EnableIRQ()
         (+++) In ADC IRQ handler, call HAL_ADC_IRQHandler()
   (##) In case of using DMA to control data transfer (e.g. HAL_ADC_Start_DMA())
         (+++) Enable the DMAx interface clock using __HAL_RCC_DMAx_CLK_ENABLE()
         (+++) Configure and enable two DMA streams stream for managing data
               transfer from peripheral to memory (output stream)
         (+++) Associate the initialized DMA handle to the CRYP DMA handle
               using  __HAL_LINKDMA()
         (+++) Configure the priority and enable the NVIC for the transfer complete
               interrupt on the two DMA Streams. The output stream should have higher
               priority than the input stream.
----------------------------------------
这个说明写的不够人性化，直接看例程的过程吧。
HAL_ADC_Init(&AdcHandle)
第一步是这个，通过判断返回值确认是否初始化成功。

typedef struct
{
  ADC_TypeDef                *Instance;                /*!< Register base address */

  ADC_InitTypeDef             Init;                      /*!< ADC required parameters */

  __IO uint32_t                NbrOfCurrentConversionRank;  /*!< ADC number of current conversion rank */

  DMA_HandleTypeDef          *DMA_Handle;                /*!< Pointer DMA Handler */

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

  __IO HAL_ADC_StateTypeDef    State;                      /*!< ADC communication state */

  __IO uint32_t                ErrorCode;                /*!< ADC Error code */
}ADC_HandleTypeDef;
这个就是传递参数的结构体类型。

1万 · 2015-11-12 19:08

/*##-1- Configure the ADC peripheral #######################################*/
  AdcHandle.Instance       = ADCx;

  AdcHandle.Init.ClockPrescaler = ADC_CLOCKPRESCALER_PCLK_DIV2;
  AdcHandle.Init.Resolution = ADC_RESOLUTION_12B;
  AdcHandle.Init.ScanConvMode = DISABLE;
  AdcHandle.Init.ContinuousConvMode = ENABLE;
  AdcHandle.Init.DiscontinuousConvMode = DISABLE;
  AdcHandle.Init.NbrOfDiscConversion = 0;
  AdcHandle.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  AdcHandle.Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T1_CC1;
  AdcHandle.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  AdcHandle.Init.NbrOfConversion = 1;
  AdcHandle.Init.DMAContinuousRequests = ENABLE;
  AdcHandle.Init.EOCSelection = DISABLE;
-----------------------------
上面是例程的初始化函数，我们发现，第一个Register base address 的Instance是赋值了一个ADCx.
#define ADCx                         ADC3
ADCx就是上面的宏ADC3.
也就是这里要传送过去的是模数转换的通道号
下面全是对  ADC_InitTypeDef             Init;类型的初始化，也就是ADC required parameters
后面那些没有被初始化的变量实际上是不需要初始化的，系统在处理过程用要存储各种变量时候使用的。

__IO uint32_t                NbrOfCurrentConversionRank;  /*!< ADC number of current conversion rank */

  DMA_HandleTypeDef          *DMA_Handle;                /*!< Pointer DMA Handler */

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

  __IO HAL_ADC_StateTypeDef    State;                      /*!< ADC communication state */

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

1万 · 2015-11-12 20:02

/*##-2- Configure ADC regular channel ######################################*/
  sConfig.Channel = ADCx_CHANNEL;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
  sConfig.Offset = 0;

  if(HAL_ADC_ConfigChannel(&AdcHandle, &sConfig) != HAL_OK)
  {
/* Channel Configuration Error */
Error_Handler();
  }
----------------------
接下来就是这个配置，那么这个结构体是什么内容呢？
{
  uint32_t Channel;       /*!< The ADC channel to configure.
                              This parameter can be a value of @ref ADC_channels */
  uint32_t Rank;          /*!< The rank in the regular group sequencer.
                              This parameter must be a number between Min_Data = 1 and Max_Data = 16 */
  uint32_t SamplingTime; /*!< The sample time value to be set for the selected channel.
                              This parameter can be a value of @ref ADC_sampling_times */
  uint32_t Offset;       /*!< Reserved for future use, can be set to 0 */
}ADC_ChannelConfTypeDef;

结构体一共四个成员，分别是：ADC通道，这里是选择的8通道，也就是使用的是ADC3的第八通道，好难理解。。。
第二个，RANK,就是排名的意思，队列。也就是在分组的序列。可以选择的参数有1到16的整数。
第三个采样时间，
第四个是，偏移。保留使用，可以设置为0

1万 · 2015-11-12 20:05

/*##-3- Start the conversion process and enable interrupt ##################*/
  if(HAL_ADC_Start_DMA(&AdcHandle, (uint32_t*)&uhADCxConvertedValue, 1) != HAL_OK)
  {
/* Start Conversation Error */
Error_Handler();
  }

下面就是开始启动转换了，照样传递那刚才的参数，另外传递转换后值的存储位置。
__IO uint16_t uhADCxConvertedValue = 0;
这个是初始化时候的值。

1万 · 2015-11-12 20:10

/**
  * @brief  Conversion complete callback in non blocking mode
  * @param  AdcHandle : AdcHandle handle
  * @NOTE This example shows a simple way to report end of conversion, and
  *       you can add your own implementation.
  * @retval None
  */
void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* AdcHandle)
{
  /* Turn LED3 on: Transfer process is correct */
  BSP_LED_On(LED3);
}

最后在中断里执行相关指令，就是完成转换后干啥呢，这里采用LED点亮来回应。