前言
串口可以实现单片机和上位机之间的通信，是生活中常见的通讯接口，本篇文章将以十二届蓝桥杯嵌入式部分真题为例，实现串口通信。

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5 _2 O# T9 R7 Z1.原理图以及配置元素
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: |; a+ W' `$ M. o& q- T分析:由图可知PA9为串口的TX端，PA10为串口的RX端。
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# y  @4 B! p" B- ?. {5 s6 D4 p) o2.CubeMx的配置步骤

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配置两个引脚为红框中的模式，一定要先配置引脚模式再激活串口1，否则当你没有选定PC4与PC5的模式时，串口1激活时会默认选中PC4和PC5为TX端和RX端。
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配置号PA9和PA10之后，激活串口1(题目要求波特率为9600)。

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" ]8 ^7 m; {0 i( h点击GENERATE CODE生成代码后点击Open Project即可。

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6 g1 U% ^! M7 n- F0 j8 n& B4.测试代码
interrupt.h:
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1. #ifndef __INTERRUPT_H__
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2. #define __INTERRUPT_H__
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3. 
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4. #include "main.h"
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5. 
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6. void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart);
   
7. 
   
8. #endif
   
9. 
   

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interrupt.c

1. #include "interrupt.h"
   
2. #include "usart.h"
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3. 
   
4. char RxBuffer[30];
   
5. unsigned char BufIndex = 0;
   
6. unsigned char Rxdat = 0;
   
7. 
   
8. void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
   
9. {
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10.         if(huart->Instance == USART1)
    
11.         {
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12.                 RxBuffer[BufIndex++] = Rxdat;
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13.                 HAL_UART_Receive_IT(&huart1, &Rxdat, 1);
    
14.         }
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15. }
    
16. 
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1. /* USER CODE BEGIN Header */
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2. /**
   
3.   ******************************************************************************
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4.   * @file           : main.c
   
5.   * @brief          : Main program body
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6.   ******************************************************************************
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7.   * @attention
   
8.   *
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9.   * <h2><center>© Copyright (c) 2023 STMicroelectronics.
   
10.   * All rights reserved.</center></h2>
    
11.   *
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12.   * This software component is licensed by ST under BSD 3-Clause license,
    
13.   * the "License"; You may not use this file except in compliance with the
    
14.   * License. You may obtain a copy of the License at:
    
15.   *                        opensource.org/licenses/BSD-3-Clause
    
16.   *
    
17.   ******************************************************************************
    
18.   */
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19. /* USER CODE END Header */
    
20. /* Includes ------------------------------------------------------------------*/
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21. #include "main.h"
    
22. #include "usart.h"
    
23. #include "gpio.h"
    
24. 
    
25. /* Private includes ----------------------------------------------------------*/
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26. /* USER CODE BEGIN Includes */
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27. #include "stdlib.h"
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28. #include "stdio.h"
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29. #include "string.h"
    
30. #include "interrupt.h"
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31. #include "lcd.h"
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32. /* USER CODE END Includes */
    
33. 
    
34. /* Private typedef -----------------------------------------------------------*/
    
35. /* USER CODE BEGIN PTD */
    
36. 
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37. /* USER CODE END PTD */
    
38. 
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39. /* Private define ------------------------------------------------------------*/
    
40. /* USER CODE BEGIN PD */
    
41. /* USER CODE END PD */
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42. 
    
43. /* Private macro -------------------------------------------------------------*/
    
44. /* USER CODE BEGIN PM */
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45. 
    
46. /* USER CODE END PM */
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47. 
    
48. /* Private variables ---------------------------------------------------------*/
    
49. 
    
50. /* USER CODE BEGIN PV */
    
51. extern unsigned char BufIndex;
    
52. extern char RxBuffer[30];
    
53. extern unsigned char Rxdat;
    
54. /* USER CODE END PV */
    
55. 
    
56. /* Private function prototypes -----------------------------------------------*/
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57. void SystemClock_Config(void);
    
58. /* USER CODE BEGIN PFP */
    
59. void Rx_Proc(void);
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60. /* USER CODE END PFP */
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61. 
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62. /* Private user code ---------------------------------------------------------*/
    
63. /* USER CODE BEGIN 0 */
    
64. 
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65. /* USER CODE END 0 */
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66. 
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67. /**
    
68.   * @brief  The application entry point.
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69.   * @retval int
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70.   */
    
71. int main(void)
    
72. {
    
73.   /* USER CODE BEGIN 1 */
    
74. 
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75.   /* USER CODE END 1 */
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76. 
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77.   /* MCU Configuration--------------------------------------------------------*/
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78. 
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79.   /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
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80.   HAL_Init();
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81. 
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82.   /* USER CODE BEGIN Init */
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83. 
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84.   /* USER CODE END Init */
    
85. 
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86.   /* Configure the system clock */
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87.   SystemClock_Config();
    
88. 
    
89.   /* USER CODE BEGIN SysInit */
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90. 
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91.   /* USER CODE END SysInit */
    
92. 
    
93.   /* Initialize all configured peripherals */
    
94.   MX_GPIO_Init();
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95.   MX_USART1_UART_Init();
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96.   /* USER CODE BEGIN 2 */
    
97.         LCD_Init();
    
98.         LCD_Clear(Black);
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99.         LCD_SetBackColor(Black);
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100.         LCD_SetTextColor(White);
     
101.         HAL_UART_Receive_IT(&huart1, &Rxdat, 1);
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102.   /* USER CODE END 2 */
     
103. 
     
104.   /* Infinite loop */
     
105.   /* USER CODE BEGIN WHILE */
     
106.   while (1)
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107.   {
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108.     /* USER CODE END WHILE */
     
109. 
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110.     /* USER CODE BEGIN 3 */
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111.                 if(BufIndex != 0)
     
112.                 {
     
113.                         unsigned char temp = BufIndex;
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114.                         HAL_Delay(1);
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115.                         if(BufIndex == temp)
     
116.                                 Rx_Proc();
     
117.                 }
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118.   }
     
119.   /* USER CODE END 3 */
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120. }
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121. 
     
122. /**
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123.   * @brief System Clock Configuration
     
124.   * @retval None
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125.   */
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126. void SystemClock_Config(void)
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127. {
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128.   RCC_OscInitTypeDef RCC_OscInitStruct = {0};
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129.   RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
     
130.   RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
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131. 
     
132.   /** Configure the main internal regulator output voltage
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133.   */
     
134.   HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
     
135.   /** Initializes the RCC Oscillators according to the specified parameters
     
136.   * in the RCC_OscInitTypeDef structure.
     
137.   */
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138.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     
139.   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
     
140.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
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141.   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     
142.   RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV3;
     
143.   RCC_OscInitStruct.PLL.PLLN = 20;
     
144.   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
     
145.   RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
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146.   RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
     
147.   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
     
148.   {
     
149.     Error_Handler();
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150.   }
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151.   /** Initializes the CPU, AHB and APB buses clocks
     
152.   */
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153.   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
     
154.                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
     
155.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     
156.   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
     
157.   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
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158.   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
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159. 
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160.   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
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161.   {
     
162.     Error_Handler();
     
163.   }
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164.   /** Initializes the peripherals clocks
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165.   */
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166.   PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
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167.   PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
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168.   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
     
169.   {
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170.     Error_Handler();
     
171.   }
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172. }
     
173. 
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174. /* USER CODE BEGIN 4 */
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175. int fputc(int ch, FILE *f)
     
176. {
     
177.         HAL_UART_Transmit(&huart1, (unsigned char *)&ch, 1, HAL_MAX_DELAY);
     
178.         return ch;
     
179. }
     
180. 
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181. void Rx_Proc(void)
     
182. {
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183.         if(BufIndex == 22)
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184.         {
     
185.                 char car_type[5];
     
186.                 char car_data[5];
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187.           char car_time[13];
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188.                 sscanf(RxBuffer, "%4s:%4s:%12s", car_type, car_data, car_time);
     
189.                 LCD_DisplayStringLine(Line0, (unsigned char*)car_type);
     
190.                 LCD_DisplayStringLine(Line1, (unsigned char*)car_data);
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191.                 LCD_DisplayStringLine(Line2, (unsigned char*)car_time);
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192.         }
     
193.         else
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194.         {
     
195.                 printf("Error\n");
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196.         }
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197.         BufIndex = 0;
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198.         memset(RxBuffer, 0, 30);
     
199. }
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200. /* USER CODE END 4 */
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201. 
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202. /**
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203.   * @brief  This function is executed in case of error occurrence.
     
204.   * @retval None
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205.   */
     
206. void Error_Handler(void)
     
207. {
     
208.   /* USER CODE BEGIN Error_Handler_Debug */
     
209.   /* User can add his own implementation to report the HAL error return state */
     
210.   __disable_irq();
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211.   while (1)
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212.   {
     
213.   }
     
214.   /* USER CODE END Error_Handler_Debug */
     
215. }
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216. 
     
217. #ifdef  USE_FULL_ASSERT
     
218. /**
     
219.   * @brief  Reports the name of the source file and the source line number
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220.   *         where the assert_param error has occurred.
     
221.   * @param  file: pointer to the source file name
     
222.   * @param  line: assert_param error line source number
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223.   * @retval None
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224.   */
     
225. void assert_failed(uint8_t *file, uint32_t line)
     
226. {
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227.   /* USER CODE BEGIN 6 */
     
228.   /* User can add his own implementation to report the file name and line number,
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229.      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
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230.   /* USER CODE END 6 */
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231. }
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232. #endif /* USE_FULL_ASSERT */
     
233. 
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234. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
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