串口

stm32f407zgt6新建工程

发布于 2023-02-03 09:35:09 浏览：184 订阅该版

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# rt-thread studio新建stm32f407工程

rt-thread studio新建stm32f407工程，使用的版本是：2.2.6，stm32f4的支持包版本为0.2.2。先不用0.2.3，因为使用0.2.3建立的模板编译会报错。。

按照模板新建工程，默认使用内部时钟，编译，正常，串口1输出正常。修改为外部晶振，按照要求修改了代码，如下：
	
```c
void system_clock_config(int target_freq_mhz)
{
#if false
    RCC_OscInitTypeDef RCC_OscInitStruct = { 0 };
    RCC_ClkInitTypeDef RCC_ClkInitStruct = { 0 };

/** Configure the main internal regulator output voltage
     */
    __HAL_RCC_PWR_CLK_ENABLE();
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
    /** Initializes the CPU, AHB and APB busses clocks
     */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
    RCC_OscInitStruct.HSIState = RCC_HSI_ON;
    RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
    RCC_OscInitStruct.PLL.PLLM = 8;
    RCC_OscInitStruct.PLL.PLLN = target_freq_mhz;
    RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
    RCC_OscInitStruct.PLL.PLLQ = 4;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
    {
        Error_Handler();
    }
    /** Initializes the CPU, AHB and APB busses clocks
     */
    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
    {
        Error_Handler();
    }
#else
    RCC_OscInitTypeDef RCC_OscInitStruct = {0};
     RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

/** Configure the main internal regulator output voltage
     */
     __HAL_RCC_PWR_CLK_ENABLE();
     __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

/** Initializes the RCC Oscillators according to the specified parameters
     * in the RCC_OscInitTypeDef structure.
     */
     RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     RCC_OscInitStruct.HSEState = RCC_HSE_ON;
     RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
     RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     RCC_OscInitStruct.PLL.PLLM = 25;
     RCC_OscInitStruct.PLL.PLLN = 336;
     RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
     RCC_OscInitStruct.PLL.PLLQ = 4;
     if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
     {
       Error_Handler();
     }

/** Initializes the CPU, AHB and APB buses clocks
     */
     RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                                 |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
     RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
     RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
     RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
     {
       Error_Handler();
     }
#endif
}
```
同时修改了宏定义：

```c
#define BSP_CLOCK_SOURCE                  ("HSE")
#define BSP_CLOCK_SOURCE_FREQ_MHZ         ((int32_t)25)
#define BSP_CLOCK_SYSTEM_FREQ_MHZ         ((int32_t)168)
```
编译正常，调试发现输出不正常，乱码。
分析应该是时钟配置不正确，先检查系统时钟，发现不是设定的系统时钟，通过调试发现还需要修改`stm32f407zgt6\drivers\stm32f4xx_hal_conf.h`文件中的宏定义：
```c
#if !defined  (HSE_VALUE) 
  #define HSE_VALUE    ((uint32_t)25000000U) /*!< Value of the External oscillator in Hz */
#endif /* HSE_VALUE */
```
原先为8M，需要改为实际25M，重新编译调试，串口1正常输出。