hal库 用串口1 dma1_4通道设置代码

以下是基于HAL库的串口1 DMA1_4通道设置代码示例：

#include "stm32f4xx_hal.h"

UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_tx;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART1_UART_Init(void);

int main(void)
{
  HAL_Init();
  SystemClock_Config();
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_USART1_UART_Init();

  uint8_t tx_data[] = "Hello, world!\r\n";
  HAL_UART_Transmit_DMA(&huart1, tx_data, sizeof(tx_data));

  while (1)
  {
    // Do something else
  }
}

void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  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 = 84;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
  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_2) != HAL_OK)
  {
    Error_Handler();
  }
}

static void MX_USART1_UART_Init(void)
{
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }
}

static void MX_DMA_Init(void)
{
  __HAL_RCC_DMA1_CLK_ENABLE();

  hdma_usart1_tx.Instance = DMA1_Stream4;
  hdma_usart1_tx.Init.Channel = DMA_CHANNEL_4;
  hdma_usart1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
  hdma_usart1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
  hdma_usart1_tx.Init.MemInc = DMA_MINC_ENABLE;
  hdma_usart1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
  hdma_usart1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
  hdma_usart1_tx.Init.Mode = DMA_NORMAL;
  hdma_usart1_tx.Init.Priority = DMA_PRIORITY_LOW;
  hdma_usart1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
  if (HAL_DMA_Init(&hdma_usart1_tx) != HAL_OK)
  {
    Error_Handler();
  }
  __HAL_LINKDMA(&huart1, hdmatx, hdma_usart1_tx);
}

void Error_Handler(void)
{
  // Handle error
}

在上述代码中，首先使用HAL库对系统时钟、GPIO、DMA和USART1进行初始化。然后定义一个需要发送的数据数组`tx_data`，并通过调用`HAL_UART_Transmit_DMA`函数将其发送到USART1上。`HAL_UART_Transmit_DMA`函数将数据发送到USART1之前，首先将数据复制到DMA缓冲区中，并启动DMA传输。因此，该函数不会阻塞程序的执行，而是在DMA传输完成后通过回调函数通知主程序。这里使用了USART1的DMA1_4通道。