rtthread串口接收不定长数据

之前做过DMA加串口空闲中断的方式接收不定长数据，想移植过来，但是那样的话就用不上rtthread自带的信号量这个内容了，于是基于信号量做了一个不定长接收的功能，基本思路是用两个字节间的时间间隔来做区分两帧的依据，用信号量好处不用另外开定时器，代码如下：

#define SAMPLE_UART4_NAME       "uart4"       /* 需要操作的设备 */
static struct rt_semaphore      rx_sem4;      /* 信号量 */
static rt_device_t              serial4;      /* 设备句柄 *//* 接收数据回调函数 */
static rt_err_t uart4_rx_ind(rt_device_t dev, rt_size_t size)
{/* 串口接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */if (size > 0){rt_sem_release(&rx_sem4);}return RT_EOK;
}static char uart_ZIGBEE_get_char(void)
{char ch;static uint8_t rv_flag = 1;while (rt_device_read(serial4, 0, &ch, 1) == 0){rt_sem_control(&rx_sem4, RT_IPC_CMD_RESET, RT_NULL);if(rv_flag)rt_sem_take(&rx_sem4, RT_WAITING_FOREVER);else if(-RT_ETIMEOUT == rt_sem_take(&rx_sem4, 100))//超时100ms未获得串口数据  100是根据时钟节拍来定 节拍单位是1/RT_TICK_PER_SECOND 秒{rv_flag = 1; //收完一帧ch = '\n'; //也可以用别的当伪帧尾return ch;}}rv_flag = 0; //正常获取一个字节return ch;
}/* 数据解析线程 */
static void ZIGBEE_data_parsing(void)
{char rx_temp = 0, rx_len = 0;char data_buf[30] = {0};while (1){rx_temp = uart_ZIGBEE_get_char();if(rx_temp != '\n'){data_buf[(rx_len++) % 30] = rx_temp;//防止数组越界}else //开始处理一帧数据{rx_len = 0;rt_kprintf("uart4 received data is %s\n", data_buf);/* 帧数据处理 */memset(data_buf, 0, sizeof(data_buf));}}
}static int uart4_ZIGBEE(void)
{rt_err_t ret = RT_EOK;/* 查找系统中的串口设备 */serial4 = rt_device_find(SAMPLE_UART4_NAME);if (!serial4){rt_kprintf("find %s failed!\n", SAMPLE_UART4_NAME);return RT_ERROR;}/* 初始化信号量 */rt_sem_init(&rx_sem4, "rx_sem4", 0, RT_IPC_FLAG_FIFO);/* 以中断接收及轮询发送模式打开串口设备 */rt_device_open(serial4, RT_DEVICE_FLAG_INT_RX);/* 设置接收回调函数 */rt_device_set_rx_indicate(serial4, uart4_rx_ind);/* 创建 serial 线程 */rt_thread_t thread = rt_thread_create("ZIG_th", (void (*)(void *parameter))ZIGBEE_data_parsing,RT_NULL, 512, RT_THREAD_PRIORITY_MAX-10, 10);/* 创建成功则启动线程 */if (thread != RT_NULL){rt_thread_startup(thread);}else{ret = RT_ERROR;}return ret;
}INIT_APP_EXPORT(uart4_ZIGBEE);

最终效果如下：