STM32 C语言写一个请求写free modbus单个线圈代码

在STM32上使用C语言编写一个FreeModbus协议的单个线圈写入请求，通常涉及到HAL库的调用以及FreeModbus库的功能。以下是一个简单的示例：

#include "FreeModbus.h"
#include "stm32f1xx_hal.h"

// 假设你要操作的线圈地址是0x01
uint16_t coilAddress = 0x01;
uint16_t newCoilState = 1; // 新状态，1代表接通

void writeSingleCoil(uint16_t address, uint16_t state) {
    FreeModbusMasterContext master;
    FreeModbusResult result;

    // 初始化FreeModbus Master context
    if (FreeModbusMaster_Init(&master, &g_pBaudRate, g_pDataBits, g_pParity, g_pStopBits, g_pMode)) {
        // 连接到FreeModbus Slave
        result = FreeModbusMaster_Connect(&master, "127.0.0.1", FreeModbus_TCP);
        if (result == FM_OK) {
            // 发送写单个线圈请求
            result = FreeModbusMaster_WriteSingle Coil(&master, address, 1, &newCoilState); // 1表示只发送一次
            if (result == FM_OK) {
                // 如果写入成功，这里可以添加日志或者通知
                printf("Write Single Coil successful at address %d with state %d.\n", address, newCoilState);
            } else {
                printf("Error writing single coil: %d\n", result);
            }
            FreeModbusMaster_Disconnect(&master);
        } else {
            printf("Error connecting to slave: %d\n", result);
        }
        FreeModbusMaster_Free(&master);
    }
}

// 调用函数并传入线圈地址和新状态
writeSingleCoil(coilAddress, newCoilState);

请注意，这段代码假设你已经配置好了串口通信参数(`g_pBaudRate`, `g_pDataBits`, `g_pParity`, `g_pStopBits`, `g_pMode`)，并且`FreeModbus`库已链接到项目中。