分类：JQ8900

本例程是一个简单的串口通信的交互例程，通过了RT-thread系统来实现。

简要叙述程序思路：

1. 创建两个进程句柄，serial与serial2。
2. 调用一系列初始化串口设备的函数，分别是rt_device_find（查找设备），rt_device_set_rx_indicate（设置接收回调函数）。
3. 启动线程，调用函数并检测接受到的信息
4. 接收到对应信息后调用函数向JQ8900模块发送命令
5. 同时保留了按钮操控的效果，通过rt_pin_attach_irq设置按钮中断函数

以下给出源码：

/*
基于RTT的手机通过esp8266操作JQ8900功放模块的一种方式
所用开发板 野火指南者
WiFi模块   ESP8266
功放模块   JQ8900
RTT版本    4.0.2（野火BSP）
*/
#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>
#ifndef KEY0_PIN_NUM
    #define KEY0_PIN_NUM      GET_PIN(A, 0) /* PA0 Key1 pin脚*/
#endif
#ifndef KEY1_PIN_NUM
    #define KEY1_PIN_NUM      GET_PIN(C, 13) /* PC13 Key2 pin脚*/
#endif
#ifndef SAMPLE_UART_NAME
#define SAMPLE_UART_NAME       "uart2"        /* JQ8900所接串口 请先事先在env中打开*/
#endif
#ifndef UART_NAME
#define UART_NAME              "uart3"        /* ESP8266所接串口*/
#endif
static rt_device_t serial;   
static rt_device_t serial2;   
struct serial_configure config = RT_SERIAL_CONFIG_DEFAULT; /* 句柄默认设置 */
static struct rt_semaphore rx_sem;
static rt_err_t uart_input(rt_device_t dev, rt_size_t size)
{
    rt_sem_release(&rx_sem);
    return RT_EOK;
}
static void Re_music(void *args)
{
    static char buffer1[4]={0xAA,0x05,0x00,0xAF};    //JQ8900上一曲命令
    rt_uint32_t tx_length;
    tx_length=4;
    int i = 0;
    while(i < 4){
    rt_device_write(serial,0,&buffer1[i],tx_length);  //循环发送
    i++;}
    rt_kprintf("jun\n");
}
static void next_music(void *args)
{
    static char buffer1[4]={0xAA,0x06,0x00,0xB0};    //JQ8900下一曲命令
    rt_uint32_t tx_length;
    tx_length=4;
    int i = 0;
    while(i < 4){
    rt_device_write(serial,0,&buffer1[i],tx_length);
    i++;}
    rt_kprintf("bian\n");
}

static void nmsl(void *parameter){
  
      char ch;

    while (1)
    {
        while (rt_device_read(serial2, -1, &ch, 1) != 1)
        {
            rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
        }
        if(ch == 'a'){         //esp8266检测接受信息，为a则调用函数
          Re_music(0);
        }
        if(ch == 'b'){
          next_music(0);
        }

}
}

static void serial_thread_entry(void *parameter)
{
  //  char ch;
    while (1)
      
    {    
    rt_pin_mode(KEY0_PIN_NUM, PIN_MODE_INPUT_PULLUP);
    rt_pin_attach_irq(KEY0_PIN_NUM, PIN_IRQ_MODE_FALLING, Re_music, RT_NULL);   //设置按钮中断回调函数
    rt_pin_irq_enable(KEY0_PIN_NUM, PIN_IRQ_ENABLE);
    rt_pin_mode(KEY1_PIN_NUM, PIN_MODE_INPUT_PULLUP);
    rt_pin_attach_irq(KEY1_PIN_NUM, PIN_IRQ_MODE_FALLING, next_music, RT_NULL);
    rt_pin_irq_enable(KEY1_PIN_NUM, PIN_IRQ_ENABLE);    
    }
}
static int mdr5(int argc, char *argv[])
{
    rt_err_t ret = RT_EOK;
    char uart_name[RT_NAME_MAX];
    if (argc == 2)
    {
        rt_strncpy(uart_name, argv[1], RT_NAME_MAX);
    }
    else
    {
        rt_strncpy(uart_name, SAMPLE_UART_NAME, RT_NAME_MAX);
    }
    serial = rt_device_find(uart_name);
    serial2 = rt_device_find(UART_NAME);
    if (!serial)
    {
        rt_kprintf("find %s failed!\n", uart_name);
        return RT_ERROR;
    }
    if (!serial2)
    {
        rt_kprintf("find %s failed!\n", UART_NAME);
        return RT_ERROR;
    }
    rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
    rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);
    config.baud_rate = BAUD_RATE_9600;    //串口设置为9600
    config.data_bits = DATA_BITS_8;
    config.stop_bits = STOP_BITS_1;
    config.parity = PARITY_NONE;
    rt_device_control(serial, RT_DEVICE_CTRL_CONFIG, &config);
    rt_device_set_rx_indicate(serial, uart_input);
    
    rt_device_open(serial2, RT_DEVICE_FLAG_INT_RX);
    rt_device_set_rx_indicate(serial2, uart_input);
    rt_thread_t thread1 = rt_thread_create("serial2", nmsl, RT_NULL, 1024, 25, 10);
        if (thread1 != RT_NULL)
    {
        rt_thread_startup(thread1);
    }
    else
    {
        ret = RT_ERROR;
    }
    
    
    rt_thread_t thread = rt_thread_create("serial", serial_thread_entry, RT_NULL, 1024, 25, 10);
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
    else
    {
        ret = RT_ERROR;
    }
    return ret;
}
MSH_CMD_EXPORT(mdr5, uart JUN);

值得注意的是，JQ8900模块的波特率是9600，需要使用rt_device_control函数来设置串口波特率，而esp8266则不用

本程序还设置了一个接受信号量，用来在串口接收到信息之后发送信号量，来表示已经接受到数据。