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-GPIO

ML302模块一共有20路GPIO，但是有些GPIO是和串口I2CSPI共用的，所以实际上没有那么多

GPIO输出

// 测试GPIO 19
int test_gpio = 19;
cm_gpio_cfg_t cfg;         //GPIO设置结构体
cfg.id = test_gpio;        //ID号
cfg.dir = CM_GPIO_OUT;     //方向设置：CM_GPIO_OUT输出,CM_GPIO_IN输入
cfg.irq_enable = 0;        //使能
cm_gpio_init(&cfg);        //初始化传入设置结构体
cm_gpio_pull_config(test_gpio, CM_GPIO_PULL_UP);    //设置上下拉,CM_GPIO_PULL_DOWN ,CM_GPIO_PULL_UPosDelay(5000);                            //SDK自带延时函数
cm_gpio_write(test_gpio,CM_GPIO_HIGH);    // 写GPIO，让GPIO19高电平
osDelay(5000);
cm_gpio_write(test_gpio,CM_GPIO_LOW);    // 写GPIO，让GPIO19低电平
osDelay(5000);

GPIO输入

//    设置GPIO20 读
int read_gpio = 20;
cm_gpio_cfg_t read_cfg;
read_cfg.id = read_gpio;
read_cfg.dir = CM_GPIO_IN;
read_cfg.irq_enable = 0;
cm_gpio_init(&read_cfg);if(cm_gpio_read(20) == 1){// 干啥干啥干啥
}