用HAL库写GET_ADC(uint8_t ch)函数，实现读取PA3 PA4口

好的，下面是用HAL库写GET_ADC(uint8_t ch)函数的代码实现：

#include "stm32f1xx_hal.h"

ADC_HandleTypeDef hadc1;

/** 
  * @brief  Initializes the ADC MSP.
  * @param  hadc: ADC handle
  * @retval None
  */
void HAL_ADC_MspInit(ADC_HandleTypeDef* hadc)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(hadc->Instance==ADC1)
  {
    /* Peripheral clock enable */
    __HAL_RCC_ADC1_CLK_ENABLE();
  
    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**ADC1 GPIO Configuration    
    PA3     ------> ADC1_IN3
    PA4     ------> ADC1_IN4 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_3|GPIO_PIN_4;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  }
}

/** 
  * @brief  DeInitializes the ADC MSP.
  * @param  hadc: ADC handle
  * @retval None
  */
void HAL_ADC_MspDeInit(ADC_HandleTypeDef* hadc)
{
  if(hadc->Instance==ADC1)
  {
    /* Peripheral clock disable */
    __HAL_RCC_ADC1_CLK_DISABLE();
  
    /**ADC1 GPIO Configuration    
    PA3     ------> ADC1_IN3
    PA4     ------> ADC1_IN4 
    */
    HAL_GPIO_DeInit(GPIOA, GPIO_PIN_3|GPIO_PIN_4);
  }
}

/**
  * @brief  Get ADC value.
  * @param  ch: ADC channel.
  * @retval ADC value.
  */
uint16_t GET_ADC(uint8_t ch)
{
    ADC_ChannelConfTypeDef sConfig = {0};
    uint16_t adc_value;

    /* Initialize ADC */
    hadc1.Instance = ADC1;
    hadc1.Init.ScanConvMode = DISABLE;
    hadc1.Init.ContinuousConvMode = DISABLE;
    hadc1.Init.DiscontinuousConvMode = DISABLE;
    hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START;
    hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
    hadc1.Init.NbrOfConversion = 1;
    if (HAL_ADC_Init(&hadc1) != HAL_OK)
    {
        Error_Handler();
    }

    /* Configure ADC channel */
    sConfig.Channel = ch == 0 ? ADC_CHANNEL_3 : ADC_CHANNEL_4;
    sConfig.Rank = ADC_REGULAR_RANK_1;
    sConfig.SamplingTime = ADC_SAMPLETIME_13CYCLES_5;
    if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
    {
        Error_Handler();
    }

    /* Start ADC conversion */
    if (HAL_ADC_Start(&hadc1) != HAL_OK)
    {
        Error_Handler();
    }

    /* Wait for ADC conversion to complete */
    if (HAL_ADC_PollForConversion(&hadc1, 100) != HAL_OK)
    {
        Error_Handler();
    }

    /* Get ADC value */
    adc_value = HAL_ADC_GetValue(&hadc1);

    /* Stop ADC conversion */
    if (HAL_ADC_Stop(&hadc1) != HAL_OK)
    {
        Error_Handler();
    }

    /* De-initialize ADC */
    HAL_ADC_DeInit(&hadc1);

    return adc_value;
}

调用方式为：

uint16_t adc_value1, adc_value2;
adc_value1 = GET_ADC(0); // 读取PA3口的ADC值
adc_value2 = GET_ADC(1); // 读取PA4口的ADC值

这段代码会初始化ADC，并通过GET_ADC函数读取指定的ADC通道上的值。