[分享]stm32+rt 串口操作实例

发布于 2013-03-14 13:48:43 浏览：5000 订阅该版

大家好，在一般情况下，我们处理USART操作都是一个字符一个字符收到，到时候进行打印输出。
我现在实现的方式是，接收的字符放入缓冲中，设置一个超时定时器。等超时后处理对应的buffer就可以了。
大体代码如下:

```#define USART_BUFFER_SIZE 255
/* 定时器的控制块 */
static struct rt_timer timer_uart_tg;
static char tg_timeout_start = RT_FALSE;
char tg_uart_buffer[USART_BUFFER_SIZE];
rt_uint8_t tg_buffer_position = 0 ;

void timer_static_init()
{
	/* 初始化定时器 */
	rt_timer_init(&timer_uart_tg, "timer_tg",  /* 定时器名字是 timer1 */
		tg_read_timeout, /* 超时时回调的处理函数 */
		RT_NULL, /* 超时函数的入口参数 */
		10, /* 定时长度，以OS Tick为单位，即10个OS Tick */
		RT_TIMER_FLAG_ONE_SHOT); /* 单次定时器 */

}

//串口中断接收函数
static rt_err_t tg_rx_ind(rt_device_t device, rt_size_t size)
{
	//RT_ASSERT(shell != RT_NULL);

/* release semaphore to let finsh thread rx data */
	//rt_sem_release(&shell->rx_sem);
	//先不用线程的方式

char ch;
	/* read one character from device */
	while (rt_device_read(device, 0, &ch, 1) == 1)
	{
		/* handle CR key */
		if (ch == '
')
		{
			char next;

if (rt_device_read(device, 0, &next, 1) == 1)
				ch = next;
			else ch = '
';
		}
		
		//rt_kprintf("%c", ch);

if (tg_timeout_start == RT_FALSE)
		{
			tg_timeout_start = RT_TRUE;
			/* 启动定时器 */
			rt_timer_start(&timer_uart_tg);

}

///* it's a large line, discard it */
		if (tg_buffer_position >= USART_BUFFER_SIZE) tg_buffer_position = 0;

///* normal character */
		tg_uart_buffer[tg_buffer_position] = ch; ch = 0;
		tg_buffer_position ++;
		//shell->use_history = 0; /* it's a new command */

} /* end of device read */

return RT_EOK;
}

/* 定时器tg超时函数 */
static void tg_read_timeout(void* parameter)
{
	//rt_kprintf("one shot timer is timeout
");
	rt_uint8_t position = 0;
	tg_timeout_start = RT_FALSE;
	tg_uart_buffer[tg_buffer_position] = 0;

for (position=0; position<tg_buffer_position; position++)
	{
		rt_kprintf("%02x ",tg_uart_buffer[position]);
	}
	
	rt_kprintf("
");

tg_buffer_position = 0;

}```

大体就是这些了，和大家共同分享一起进步.