主函数文件，请直接关注自己写上去的代码：

直接看43行代码：#include 'stdio.h'//要添加这个头文件

还有97行到112行：实现用HAL库函数和printf函数发送数据

  1 /**

  2   ******************************************************************************

  3   * File Name          : main.c

  4   * Description        : Main program body

  5   ******************************************************************************

  6   ** This notice applies to any and all portions of this file

  7   * that are not between comment pairs USER CODE BEGIN and

  8   * USER CODE END. Other portions of this file, whether 

  9   * inserted by the user or by software development tools

 10   * are owned by their respective copyright owners.

 11   *

 12   * COPYRIGHT(c) 2017 STMicroelectronics

 13   *

 14   * Redistribution and use in source and binary forms, with or without modification,

 15   * are permitted provided that the following conditions are met:

 16   *   1. Redistributions of source code must retain the above copyright notice,

 17   *      this list of conditions and the following disclaimer.

 18   *   2. Redistributions in binary form must reproduce the above copyright notice,

 19   *      this list of conditions and the following disclaimer in the documentation

 20   *      and/or other materials provided with the distribution.

 21   *   3. Neither the name of STMicroelectronics nor the names of its contributors

 22   *      may be used to endorse or promote products derived from this software

 23   *      without specific prior written permission.

 24   *

 25   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS'

 26   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 27   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 28   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

 29   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 30   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

 31   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

 32   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

 33   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 34   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 35   *

 36   ******************************************************************************

 37   */

 38 /* Includes ------------------------------------------------------------------*/

 39 #include 'main.h'

 40 #include 'stm32f1xx_hal.h'

 41 

 42 /* USER CODE BEGIN Includes */

 43 #include 'stdio.h'//添加这个头文件

 44 /* USER CODE END Includes */

 45 

 46 /* Private variables ---------------------------------------------------------*/

 47 UART_HandleTypeDef huart1;

 48 

 49 /* USER CODE BEGIN PV */

 50 /* Private variables ---------------------------------------------------------*/

 51 

 52 /* USER CODE END PV */

 53 

 54 /* Private function prototypes -----------------------------------------------*/

 55 void SystemClock_Config(void);

 56 static void MX_GPIO_Init(void);

 57 static void MX_USART1_UART_Init(void);

 58 

 59 /* USER CODE BEGIN PFP */

 60 /* Private function prototypes -----------------------------------------------*/

 61 

 62 /* USER CODE END PFP */

 63 

 64 /* USER CODE BEGIN 0 */

 65 

 66 /* USER CODE END 0 */

 67 

 68 int main(void)

 69 {

 70 

 71   /* USER CODE BEGIN 1 */

 72 

 73   /* USER CODE END 1 */

 74 

 75   /* MCU Configuration----------------------------------------------------------*/

 76 

 77   /* Reset of all peripherals, Initializes the Flash interface and the Systick. */

 78   HAL_Init();

 79 

 80   /* USER CODE BEGIN Init */

 81 

 82   /* USER CODE END Init */

 83 

 84   /* Configure the system clock */

 85   SystemClock_Config();

 86 

 87   /* USER CODE BEGIN SysInit */

 88 

 89   /* USER CODE END SysInit */

 90 

 91   /* Initialize all configured peripherals */

 92   MX_GPIO_Init();

 93   MX_USART1_UART_Init();

 94 

 95   /* USER CODE BEGIN 2 */

 96 

 97 HAL_UART_Transmit (&huart1,'使用HAL库函数发送数据n',21,1000);

 98 printf('n使用函数Printf函数发送数据n');

 99 

100 char t;

101 while(1)

102 {

103     scanf('%c',&t);//接受的t的数值

104     if(t=='0')

105     {

106         HAL_GPIO_WritePin (GPIOB,GPIO_PIN_5,0);//给低电平，红灯亮

107     }

108     if(t=='1')

109     {

110         HAL_GPIO_WritePin (GPIOB,GPIO_PIN_5,1);//给高电平，红灯灭

111     }

112 }

113 

114 

115   /* USER CODE END 2 */

116 

117   /* Infinite loop */

118   /* USER CODE BEGIN WHILE */

119   while (1)

120   {

121   /* USER CODE END WHILE */

122 

123   /* USER CODE BEGIN 3 */

124 

125   }

126   /* USER CODE END 3 */

127 

128 }

129 

130 /** System Clock Configuration

131 */

132 void SystemClock_Config(void)

133 {

134 

135   RCC_OscInitTypeDef RCC_OscInitStruct;

136   RCC_ClkInitTypeDef RCC_ClkInitStruct;

137 

138     /**Initializes the CPU, AHB and APB busses clocks 

139     */

140   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;

141   RCC_OscInitStruct.HSIState = RCC_HSI_ON;

142   RCC_OscInitStruct.HSICalibrationValue = 16;

143   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;

144   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

145   {

146     _Error_Handler(__FILE__, __LINE__);

147   }

148 

149     /**Initializes the CPU, AHB and APB busses clocks 

150     */

151   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

152                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

153   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;

154   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

155   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

156   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

157 

158   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)

159   {

160     _Error_Handler(__FILE__, __LINE__);

161   }

162 

163     /**Configure the Systick interrupt time 

164     */

165   HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

166 

167     /**Configure the Systick 

168     */

169   HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

170 

171   /* SysTick_IRQn interrupt configuration */

172   HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);

173 }

174 

175 /* USART1 init function */

176 static void MX_USART1_UART_Init(void)

177 {

178 

179   huart1.Instance = USART1;

180   huart1.Init.BaudRate = 9600;

181   huart1.Init.WordLength = UART_WORDLENGTH_8B;

182   huart1.Init.StopBits = UART_STOPBITS_1;

183   huart1.Init.Parity = UART_PARITY_NONE;

184   huart1.Init.Mode = UART_MODE_TX_RX;

185   huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;

186   huart1.Init.OverSampling = UART_OVERSAMPLING_16;

187   if (HAL_UART_Init(&huart1) != HAL_OK)

188   {

189     _Error_Handler(__FILE__, __LINE__);

190   }

191 

192 }

193 

194 /** Configure pins as 

195         * Analog 

196         * Input 

197         * Output

198         * EVENT_OUT

199         * EXTI

200 */

201 static void MX_GPIO_Init(void)

202 {

203 

204   GPIO_InitTypeDef GPIO_InitStruct;

205 

206   /* GPIO Ports Clock Enable */

207   __HAL_RCC_GPIOA_CLK_ENABLE();

208   __HAL_RCC_GPIOB_CLK_ENABLE();

209 

210   /*Configure GPIO pin Output Level */

211   HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_RESET);

212 

213   /*Configure GPIO pin : PB5 */

214   GPIO_InitStruct.Pin = GPIO_PIN_5;

215   GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;

216   GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

217   HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

218 

219 }

220 

221 /* USER CODE BEGIN 4 */

222 

223 /* USER CODE END 4 */

224 

225 /**

226   * @brief  This function is executed in case of error occurrence.

227   * @param  None

228   * @retval None

229   */

230 void _Error_Handler(char * file, int line)