STC89C52 ESP-01 MQTT 订阅消息 C语言代码

以下是STC89C52与ESP8266 ESP-01模块通过MQTT协议进行订阅消息的C语言代码：

#include "reg52.h"
#include "stdio.h"
#include "string.h"
#include "stdlib.h"

#define uchar unsigned char
#define uint unsigned int

sbit LED=P0^0; //LED灯连接P0.0口

//串口波特率设置
#define BAUD 9600     
#define FOSC 11059200L
#define T1MS (65536-FOSC/12/1000) //1ms定时器计数值

//MQTT服务器地址和端口
#define SERVER_IP "192.168.1.100"
#define SERVER_PORT 1883

//订阅的主题
#define TOPIC "/test/topic"

//ESP8266模块发送AT指令的函数
void esp8266_cmd(char* cmd)
{
    char buf[100];
    memset(buf, 0, sizeof(buf));
    sprintf(buf, "%s\r\n", cmd);
    printf("%s", buf);
    while(1)
    {
        if(strstr(buf, "OK") || strstr(buf, "ERROR"))
            return;
        if(SBUF != 0)
            buf[strlen(buf)] = SBUF;
    }
}

//连接MQTT服务器
void mqtt_connect()
{
    char cmd[100];
    //发送MQTT连接请求
    sprintf(cmd, "AT+CIPSTART=\"TCP\",\"%s\",%d\r\n", SERVER_IP, SERVER_PORT);
    esp8266_cmd(cmd);
    sprintf(cmd, "AT+CIPSEND=%d\r\n", 34 + strlen(TOPIC));
    esp8266_cmd(cmd);
    printf("0104000000064d5154540402001e0004");
    printf("%02x", strlen(TOPIC) >> 8);
    printf("%02x", strlen(TOPIC) & 0xff);
    printf("%s", TOPIC);
    while(1)
    {
        if(strstr(cmd, "SEND OK"))
            break;
    }
}

//订阅主题
void mqtt_subscribe()
{
    char cmd[100];
    sprintf(cmd, "AT+CIPSEND=%d\r\n", 35 + strlen(TOPIC));
    esp8266_cmd(cmd);
    printf("8205");
    printf("%02x", strlen(TOPIC) >> 8);
    printf("%02x", strlen(TOPIC) & 0xff);
    printf("%s", TOPIC);
    printf("00");
    while(1)
    {
        if(strstr(cmd, "SEND OK"))
            break;
    }
}

//处理接收到的MQTT消息
void mqtt_process(char* msg)
{
    if(strstr(msg, "ON"))
        LED = 0;
    else if(strstr(msg, "OFF"))
        LED = 1;
}

//接收串口数据中断处理函数
void serial_isr() interrupt 4
{
    if(RI == 1)
    {
        RI = 0;
        SBUF = P0;
        if(SBUF == '+')
        {
            char buf[100];
            memset(buf, 0, sizeof(buf));
            uint i = 0;
            while(1)
            {
                if(SBUF != 0)
                {
                    buf[i++] = SBUF;
                    if(i >= sizeof(buf))
                        break;
                    if(strstr(buf, "OK") || strstr(buf, "ERROR"))
                        break;
                }
            }
            if(strstr(buf, TOPIC))
            {
                char msg[100];
                memset(msg, 0, sizeof(msg));
                uint j = 0;
                while(SBUF != 0)
                {
                    msg[j++] = SBUF;
                    if(j >= sizeof(msg))
                        break;
                }
                mqtt_process(msg);
            }
        }
    }
}

//定时器1中断处理函数
void timer1_isr() interrupt 3
{
    static uint cnt = 0;
    TH1 = T1MS >> 8;
    TL1 = T1MS & 0xff;
    if(++cnt >= 1000)
    {
        cnt = 0;
        LED = !LED;
    }
}

//主函数
void main()
{
    //串口初始化
    TMOD = 0x20;
    TH1 = T1MS >> 8;
    TL1 = T1MS & 0xff;
    TR1 = 1;
    SM0 = 0;
    SM1 = 1;
    REN = 1;
    ES = 1;
    EA = 1;
    //连接WiFi热点
    esp8266_cmd("AT+CWMODE=1");
    esp8266_cmd("AT+CWJAP=\"ssid\",\"password\"");
    //连接MQTT服务器并订阅主题
    mqtt_connect();
    mqtt_subscribe();
    //循环等待接收MQTT消息
    while(1);
}

需要注意的是，上述代码需要在STC89C52的环境下编译运行，且需要将ESP8266 ESP-01模块与STC89C52通过串口连接，同时需要将LED灯连接到P0.0口。另外，代码中的MQTT服务器地址、端口和订阅的主题需要根据实际情况进行修改。