例程中没有输出变量，接下来的任务就是通过串口输出 ADC1 的值了。

根据板子的设计，将串口输出到 USART3_PD9，USART3_PD8。通过新建立的项目完成硬件配置，主要是将 ADC 的函数拷贝到项目中。

1. /**
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2. 
   
3. * @brief USART3 Initialization Function
   
4. * @param None
   
5. * @retval None
   
6.   */static void MX_USART3_UART_Init(void)
   
7.   {
   
8. 
   
9. /* USER CODE BEGIN USART3_Init 0 */
   
10. 
    
11. /* USER CODE END USART3_Init 0 */
    
12. 
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13. /* USER CODE BEGIN USART3_Init 1 */
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14. 
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15. /* USER CODE END USART3_Init 1 */
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16. huart3.Instance = USART3;
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17. huart3.Init.BaudRate = 115200;
    
18. huart3.Init.WordLength = UART_WORDLENGTH_8B;
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19. huart3.Init.StopBits = UART_STOPBITS_1;
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20. huart3.Init.Parity = UART_PARITY_NONE;
    
21. huart3.Init.Mode = UART_MODE_TX_RX;
    
22. huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    
23. huart3.Init.OverSampling = UART_OVERSAMPLING_16;
    
24. huart3.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
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25. huart3.Init.ClockPrescaler = UART_PRESCALER_DIV1;
    
26. huart3.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
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27. if (HAL_UART_Init(&huart3) != HAL_OK)
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28. {
    
29.    Error_Handler();
    
30. }
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31. if (HAL_UARTEx_SetTxFifoThreshold(&huart3, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
    
32. {
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33.    Error_Handler();
    
34. }
    
35. if (HAL_UARTEx_SetRxFifoThreshold(&huart3, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
    
36. {
    
37.    Error_Handler();
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38. }
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39. if (HAL_UARTEx_DisableFifoMode(&huart3) != HAL_OK)
    
40. {
    
41.    Error_Handler();
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42. }
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43. /* USER CODE BEGIN USART3_Init 2 */
    
44. 
    
45. /* USER CODE END USART3_Init 2 */
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46. 
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47. }

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将例程拷贝到例程中，然后是 printf 函数的设置，main.c 中包含 #include <stdio.h>

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1. #if defined(__ICCARM__)
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2. /* New definition from EWARM V9, compatible with EWARM8 */
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3. int iar_fputc(int ch);
   
4. #define PUTCHAR_PROTOTYPE int putchar(int ch)
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5. #elif defined ( __CC_ARM ) || defined(__ARMCC_VERSION)
   
6. /* ARM Compiler 5/6*/
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7. #define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
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8. #elif defined(__GNUC__)
   
9. #define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
   
10. #endif /* __ICCARM__ */

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还有就是声明 PUTCHAR_PROTOTYPE 宏。
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1. /* USER CODE BEGIN 4 */
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2. /**
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3. 
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4. * @brief  Retargets the C library printf function to the USART.
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5. * @param  None
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6. * @retval None
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7.   */
   
8.   PUTCHAR_PROTOTYPE
   
9.   {
   
10.   /* Place your implementation of fputc here */
    
11.   /* e.g. write a character to the USART1 and Loop until the end of transmission */
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12.   HAL_UART_Transmit(&huart3, (uint8_t *)&ch, 1, 0xFFFF);
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13. 
    
14. return ch;
    
15. }
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16. /* USER CODE END 4 */
    

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还需要一个 keil 的设置 MicroLib。

1. while (1)
   
2. {
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3.    /* USER CODE END WHILE */
   
4. /* Start ADC group regular conversion */
   
5.    if (HAL_ADC_Start_IT(&hadc1) != HAL_OK)
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6.    {
   
7.      /* Error: ADC conversion start could not be performed */
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8.      Error_Handler();
   
9.    }
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10. 
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11.    /* For this example purpose, wait until conversion is done */
    
12.    while (ubAdcGrpRegularUnitaryConvStatus != 1);
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13.    printf("mVolt=%d \n",uhADCxConvertedData_Voltage_mVolt);  
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14.    /* Reset status variable of ADC group regular unitary conversion */
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15.    ubAdcGrpRegularUnitaryConvStatus = 0;
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16. HAL_Delay(500);
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17.    /* USER CODE BEGIN 3 */
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18. }

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下面是输出的结果
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测试中我使用了我的一个宝贝，信号发生器。ADC 的性能和以往的ST差不多。
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( `1 O6 b$ N8 X* r+ I. s! T% b; L来源：EEWORLD论坛网友 bigbat 版权归原作者所有


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