232接口怎么驱动，在stm32平台写一个C语言的例程

在STM32平台上使用RS-232接口进行串口通信，需要进行如下配置：

1. 配置串口的波特率、数据位、停止位和校验位等参数；

2. 配置串口的中断或者DMA模式，以实现接收和发送数据；

3. 编写相应的中断服务函数或者DMA回调函数，处理接收和发送数据；

4. 调用相应的库函数，进行串口的初始化、发送和接收操作。

以下是一个简单的C语言例程，用于在STM32平台上驱动RS-232接口进行串口通信:

#include "stm32f4xx.h"
#include "stm32f4xx_hal.h"

#define UART_TX_Pin GPIO_PIN_9
#define UART_TX_GPIO_Port GPIOA
#define UART_RX_Pin GPIO_PIN_10
#define UART_RX_GPIO_Port GPIOA

UART_HandleTypeDef huart2;

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);

int main(void)
{
  HAL_Init();

  SystemClock_Config();

  MX_GPIO_Init();
  MX_USART2_UART_Init();

  while (1)
  {
    uint8_t data = 0x55;
    HAL_UART_Transmit(&huart2, &data, 1, 100);
    HAL_Delay(1000);
  }
}

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 = 50;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  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_3) != HAL_OK)
  {
    Error_Handler();
  }
}

static void MX_USART2_UART_Init(void)
{
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
}

static void MX_GPIO_Init(void)
{
  __HAL_RCC_GPIOA_CLK_ENABLE();

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin = UART_TX_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
  HAL_GPIO_Init(UART_TX_GPIO_Port, &GPIO_InitStruct);

  GPIO_InitStruct.Pin = UART_RX_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
  HAL_GPIO_Init(UART_RX_GPIO_Port, &GPIO_InitStruct);
}

void HAL_UART_MspInit(UART_HandleTypeDef *huart)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if (huart->Instance == USART2)
  {
    __HAL_RCC_USART2_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();

    GPIO_InitStruct.Pin = UART_TX_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
    HAL_GPIO_Init(UART_TX_GPIO_Port, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = UART_RX_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
    HAL_GPIO_Init(UART_RX_GPIO_Port, &GPIO_InitStruct);
  }
}

void HAL_UART_MspDeInit(UART_HandleTypeDef *huart)
{
  if (huart->Instance == USART2)
  {
    __HAL_RCC_USART2_CLK_DISABLE();

    HAL_GPIO_DeInit(UART_TX_GPIO_Port, UART_TX_Pin);
    HAL_GPIO_DeInit(UART_RX_GPIO_Port, UART_RX_Pin);
  }
}

在以上的例程中，我们通过使用HAL库函数来初始化串口，并调用HAL_UART_Transmit()函数向串口发送数据。需要注意的是，这里使用的是USART2串口，使用的GPIO管脚是PA9和PA10。如果需要使用其他串口，需要相应地修改代码。

同时，为了保证串口的稳定性和可靠性，在实际使用中还需要根据具体的需求进行相应的配置和调试。