写一段stm32与esp8266串口通信的代码

好的，以下是一段stm32与esp8266串口通信的代码：

#include "stm32f10x.h"

void USART1_Init(void) {
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    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_Rx | USART_Mode_Tx;

    USART_Init(USART1, &USART_InitStructure);

    USART_Cmd(USART1, ENABLE);
}

void USART1_SendByte(uint8_t byte) {
    while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    USART_SendData(USART1, byte);
}

void USART1_SendString(char* str) {
    while (*str) {
        USART1_SendByte(*str++);
    }
}

void USART2_Init(void) {
    USART_InitTypeDef USART_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    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_Rx | USART_Mode_Tx;

    USART_Init(USART2, &USART_InitStructure);

    USART_Cmd(USART2, ENABLE);
}

int main(void) {
    char recv;

    USART1_Init();
    USART2_Init();

    while (1) {
        if (USART_GetFlagStatus(USART2, USART_FLAG_RXNE) != RESET) {
            recv = USART_ReceiveData(USART2);
            USART1_SendByte(recv);
        }

        if (USART_GetFlagStatus(USART1, USART_FLAG_RXNE) != RESET) {
            recv = USART_ReceiveData(USART1);
            USART2_SendByte(recv);
        }
    }
}

这是一个简单的串口通信代码，利用stm32和esp8266之间的串口1和串口2实现数据的收发。其中，USART1接收到数据后会将数据发送到USART2，USART2接收到数据后会将数据发送回USART1。这样，两个串口之间就实现了数据的互发。