RT-Thread-AB32VG1之UART通讯RT-Thread问答社区

AB32VG1之UART通讯

发布于 2021-05-09 19:35:49 浏览：1235 订阅该版

[tocm]

# 1、UART详解
在CSDN上已经有大神详细的说明过了，[UART详解](https://blog.csdn.net/sternlycore/article/details/85244515?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522162055846516780366512467%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=162055846516780366512467&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~sobaiduend~default-2-85244515.first_rank_v2_pc_rank_v29&utm_term=UART%E8%AF%A6%E8%A7%A3)，百度上资源也很多，这里不详细介绍了。
# 2、硬件
TTL转RS232模块一个，蓝讯UART1。
串口参数为：波特率9600、停止位1、数据位8、无校验。
![image.png](https://oss-club.rt-thread.org/uploads/20210509/b3e54f0befce65f3255901f438981c95.png)
# 3、软件
## 3.1、开启UART1
在硬件中使能UART1。
![image.png](https://oss-club.rt-thread.org/uploads/20210509/ea17d0cc8be693944bf45f84f1fc30aa.png)
保存后自动添加进工程。
![image.png](https://oss-club.rt-thread.org/uploads/20210509/17ebce8cbf2af8ba48c811f0d6e392f8.png)
## 3.2、修改UART回调函数
1.0.5版本中串口的回调函数仅做了UART0的处理，其它串口未进行处理，所以需要修改，函数在drv_usart.c下，修改后的回调函数代码如下：
```
void uart_irq_process(struct rt_serial_device *serial)
{
    int ch = -1;
    rt_base_t level;
    struct rt_serial_rx_fifo* rx_fifo;

/* interrupt mode receive */
    rx_fifo = (struct rt_serial_rx_fifo*)serial->serial_rx;
    RT_ASSERT(rx_fifo != RT_NULL);

while (1)
    {
        ch = serial->ops->getc(serial);
        if (ch == -1) break;

/* disable interrupt */
        level = rt_hw_interrupt_disable();

rx_fifo->buffer[rx_fifo->put_index] = ch;
        rx_fifo->put_index += 1;
        if (rx_fifo->put_index >= serial->config.bufsz) rx_fifo->put_index = 0;

/* if the next position is read index, discard this 'read char' */
        if (rx_fifo->put_index == rx_fifo->get_index)
        {
            rx_fifo->get_index += 1;
            rx_fifo->is_full = RT_TRUE;
            if (rx_fifo->get_index >= serial->config.bufsz) rx_fifo->get_index = 0;

// _serial_check_buffer_size();
        }

/* enable interrupt */
        rt_hw_interrupt_enable(level);
    }

if(serial == &uart_obj[0].serial)
    {
       rt_size_t rx_length;

/* get rx length */
       level = rt_hw_interrupt_disable();
       rx_length = (rx_fifo->put_index >= rx_fifo->get_index)? (rx_fifo->put_index - rx_fifo->get_index):
           (serial->config.bufsz - (rx_fifo->get_index - rx_fifo->put_index));
       rt_hw_interrupt_enable(level);

if (rx_length)
       {
           shell_rx_ind();
       }
    }
    else
    {
       /* invoke callback */
       if (serial->parent.rx_indicate != RT_NULL)
       {
           rt_size_t rx_length;

/* get rx length */
           level = rt_hw_interrupt_disable();
           rx_length = (rx_fifo->put_index >= rx_fifo->get_index)? (rx_fifo->put_index - rx_fifo->get_index):
               (serial->config.bufsz - (rx_fifo->get_index - rx_fifo->put_index));
           rt_hw_interrupt_enable(level);

if (rx_length)
           {
               serial->parent.rx_indicate(&serial->parent, rx_length);
           }
       }
    }
}
```
添加串口例程，这里添加的是官网[UART设备](https://www.rt-thread.org/document/site/programming-manual/device/uart/uart/)中的第一个例程，既一发一回。
# 4、测试
开机收到hello RT-Thread!，并且发送什么回复什么，测试完成。
![image.png](https://oss-club.rt-thread.org/uploads/20210509/d5f78ada1fd8e94c7872504391ed4c2b.png)
# 5、代码地址
https://gitee.com/werper/ab32-vg1