stm32与esp8266串口2通信的代码

下面是一个简单的示例代码，演示了如何在STM32和ESP8266之间使用USART2进行串口通信。在这个示例中，STM32发送一个字符串给ESP8266，然后等待ESP8266的响应。

#include "stm32f10x.h"

#define USART2_TX_PIN GPIO_Pin_2
#define USART2_RX_PIN GPIO_Pin_3
#define USART2_GPIO GPIOA

USART_InitTypeDef USART_InitStructure;

void USART2_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO | RCC_APB2Periph_USART1, ENABLE);

  // Configure USART2 Tx (PA.2) as alternate function push-pull
  GPIO_InitStructure.GPIO_Pin = USART2_TX_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(USART2_GPIO, &GPIO_InitStructure);

  // Configure USART2 Rx (PA.3) as input floating
  GPIO_InitStructure.GPIO_Pin = USART2_RX_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(USART2_GPIO, &GPIO_InitStructure);

  // Configure USART2
  USART_InitStructure.USART_BaudRate = 115200;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
  USART_Init(USART2, &USART_InitStructure);

  // Enable USART2
  USART_Cmd(USART2, ENABLE);
}

void USART2_SendString(char* s)
{
  while(*s)
  {
    // Wait until data register is empty
    while(!(USART2->SR & USART_SR_TXE));
    USART_SendData(USART2, *s++);
  }
}

int main(void)
{
  char* message = "Hello, ESP8266!";

  USART2_Init();

  // Send message to ESP8266
  USART2_SendString(message);

  // Wait for response from ESP8266
  while(!(USART2->SR & USART_SR_RXNE));
  char response = USART_ReceiveData(USART2);

  // Do something with the response...

  while(1);

  return 0;
}

请注意，这只是一个简单的示例代码，实际实现中可能需要考虑更多的错误检测和容错处理。同时，ESP8266的串口通信也需要相应的配置和代码来处理STM32发送的数据和发送回来的响应。