中移4G模块-ML302-OpenCpu开发-CJSON

B站：https://space.bilibili.com/309103931

中移4G模块-ML302专栏：https://blog.csdn.net/qq_33259323/category_10453372.html

中移4G模块-ML302文集：https://www.bilibili.com/read/readlist/rl328642

1.中移4G模块-ML302-OpenCpu开发-(固件编译和烧录)

https://blog.csdn.net/qq_33259323/article/details/108586847

https://www.bilibili.com/read/cv7876504

2.中移4G模块-ML302-OpenCpu开发-(MQTT连接阿里云)

https://blog.csdn.net/qq_33259323/article/details/108638945

https://www.bilibili.com/read/cv7876527

2.1中移4G模块-ML302-OpenCpu开发-(MQTT连接阿里云-订阅主题)

https://blog.csdn.net/qq_33259323/article/details/108960540

https://www.bilibili.com/read/cv7879954

2.2中移4G模块-ML302-OpenCpu开发-(MQTT连接阿里云-接收和发送数据)

https://blog.csdn.net/qq_33259323/article/details/108964810

https://www.bilibili.com/read/cv7886836

2.3中移4G模块-ML302-OpenCpu开发-(MQTT连接阿里云-RRPC通讯)

https://blog.csdn.net/qq_33259323/article/details/108965071

https://www.bilibili.com/read/cv7888259

3.中移4G模块-ML302-OpenCpu开发-串口开发

https://blog.csdn.net/qq_33259323/article/details/108974888

https://www.bilibili.com/read/cv7888865

4.中移4G模块-ML302-OpenCpu开发-51单片机串口转I2C

https://blog.csdn.net/qq_33259323/article/details/109020642

https://www.bilibili.com/read/cv7922942

5.中移4G模块-ML302-OpenCpu开发-MCP23017输入/输出

https://blog.csdn.net/qq_33259323/article/details/109109136

https://www.bilibili.com/read/cv7969395

7.中移4G模块-ML302-OpenCpu开发-PCF8591测量电压

https://blog.csdn.net/qq_33259323/article/details/109109266

https://www.bilibili.com/read/cv7969365

8.中移4G模块-ML302-OpenCpu开发-GPIO

https://blog.csdn.net/qq_33259323/article/details/108960947

https://www.bilibili.com/read/cv7877192

9.中移4G模块-ML302-OpenCpu开发-ADC

https://blog.csdn.net/qq_33259323/article/details/109020864

https://www.bilibili.com/read/cv7922958

10.中移4G模块-ML302-OpenCpu开发-CJSON

https://blog.csdn.net/qq_33259323/article/details/109020898

https://www.bilibili.com/read/cv7923020

11.中移4G模块-ML302-OpenCpu开发-HTTP

https://blog.csdn.net/qq_33259323/article/details/109020904

https://www.bilibili.com/read/cv7923054

中移4G模块-ML302-OpenCpu开发-CJSON

JSON转字符串

    cJSON *root=NULL;
    cJSON *sub_js=NULL;
    char *out=NULL;
    
    root = cJSON_CreateObject();
    cJSON_AddStringToObject(root, "version", "V1.1.0");
    cJSON_AddStringToObject(root, "imei", "1xxxxxxxxxxxxxxxx");
    cJSON_AddItemToObject(root, "data", sub_js = cJSON_CreateObject());
    cJSON_AddNumberToObject(sub_js, "status", 1);
    cJSON_AddTrueToObject(sub_js, "material");
    cJSON_AddTrueToObject(sub_js, "power_on");
    cJSON_AddNumberToObject(sub_js, "qty", 123);
    cJSON_AddStringToObject(root, "dt", "2020-01-07T05:15:52");
    
    out=cJSON_Print(root);
    cJSON_Delete(root); 
    cm_printf("[CJSON]:\n");
    cm_printf("%s\n",out);    
    cJSON_free(out);

字符串转JSON

    char * json = "{ \"json\" : { \"id\":1, \"nodeId\":11, \"deviceId\":111, \"deviceName\":\"aaa\", \"ieee\":\"01212\", \"ep\":\"1111\", \"type\":\"bbb\" }}";  
    char * json1 = "{\"id\":1, \"nodeId\":11, \"deviceId\":111, \"deviceName\":\"aaa\"}";  
    cJSON * root;  
    cJSON * format;  
    int value_int;  
    char * value_string;  
    
    root = cJSON_Parse(json);   
    format = cJSON_GetObjectItem(root,"json");     
    value_int = cJSON_GetObjectItem(format,"nodeId")->valueint;   
    value_string = cJSON_GetObjectItem(format,"ieee")->valuestring;   
    cm_printf( "%d\n", value_int );  
    cm_printf( "%s\n", value_string );  
    cJSON_Delete(root);  
        
    root = cJSON_Parse(json1);   
    value_int = cJSON_GetObjectItem(root,"id")->valueint;   
    value_string = cJSON_GetObjectItem(root,"deviceName")->valuestring;   
    cm_printf( "%d\n", value_int );  
    cm_printf( "%s\n", value_string );  
    cJSON_Delete(root);