stm32f407-atk-explorer uart2不能正常工作【已解决】

发布于 2019-07-31 11:08:59 浏览：2515 订阅该版

* 本帖最后由 Liam 于 2019-7-31 16:28 编辑 *

在原子407开发板上根据RTT API手册 uart_sample.c 做串口实验，发现uart2不能正常写数据（uart3正常），2天没找到原因，来请教大家。
测试代码：
```#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>

/* defined the LED0 pin: PF9 */
#define LED0_PIN    GET_PIN(F, 9)

#define SAMPLE_UART_NAME       "uart3"
/* 用于接收消息的信号量 */
static struct rt_semaphore rx_sem;
static rt_device_t serial;

static struct rt_thread led_thread;
static rt_uint8_t led_thread_stack[512];

void led_thread_entry(void* parameter)
{
        rt_pin_mode(LED0_PIN, PIN_MODE_OUTPUT);
        
        while(1)
        {
                rt_pin_write(LED0_PIN, PIN_HIGH);
        rt_thread_mdelay(2000);
        rt_pin_write(LED0_PIN, PIN_LOW);
        rt_thread_mdelay(150);
        }
}

void thread2_entry(void* parameter)
{
        while(1)
        {
                rt_kprintf("enter %s <br>", __FUNCTION__);
                rt_thread_mdelay(1000);
        }
}

/* 接收数据回调函数 */
static rt_err_t uart_input(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 */
    rt_sem_release(&rx_sem);

return RT_EOK;
}
static void serial_thread_entry(void *parameter)
{
    char ch;

while (1)
    {
        /* 从串口读取一个字节的数据，没有读取到则等待接收信号量 */
        while (rt_device_read(serial, -1, &ch, 1) != 1)
        {
            /* 阻塞等待接收信号量，等到信号量后再次读取数据 */
            rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
        }
        
        rt_device_write(serial, 0, &ch, 1);
    }
}

static int uart_sample(int argc, char *argv[])
{
    rt_err_t ret = RT_EOK;
    char uart_name[RT_NAME_MAX];
    char str[] = "hello RT-Thread! <br>";

if (argc == 2)
    {
        rt_strncpy(uart_name, argv[1], RT_NAME_MAX);
    }
    else
    {
        rt_strncpy(uart_name, SAMPLE_UART_NAME, RT_NAME_MAX);
    }

/* 查找系统中的串口设备 */
    serial = rt_device_find(uart_name);
    if (!serial)
    {
        rt_kprintf("find %s failed!<br>", uart_name);
        return RT_ERROR;
    }
        
    /* 初始化信号量 */
    rt_sem_init(&rx_sem, "rx_sem", 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(serial, RT_DEVICE_FLAG_INT_RX);
    /* 设置接收回调函数 */
    rt_device_set_rx_indicate(serial, uart_input);
    /* 创建 serial 线程 */
    rt_thread_t thread = rt_thread_create("serial", serial_thread_entry, RT_NULL, 1024, 25, 10);
    /* 创建成功则启动线程 */
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
    else
    {
                rt_kprintf("create thread failed. <br>");
        ret = RT_ERROR;
    }

/* 发送字符串 */
    rt_device_write(serial, 0, str, (sizeof(str) - 1));
        
    return ret;
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(uart_sample, uart device sample);

int main(void)
{
    rt_err_t result;
        
        // thread 1        静态线程
        result = rt_thread_init(&led_thread,
                                                        "led_thread",
                                                        led_thread_entry,
                                                        RT_NULL,                        // 参数
                                                        &led_thread_stack[0],// 线程栈
                                                        sizeof(led_thread_stack),
                                                        20, 10);                        // 优先级 时间片
        if(result == RT_EOK)
                rt_thread_startup(&led_thread);

return RT_EOK;
}
```
![uart2.png](https://oss-club.rt-thread.org/uploads/201907/31/110618q8hquqzluk5u26l8.png)

![uart3.png](https://oss-club.rt-thread.org/uploads/201907/31/110618u3q30nzqm1tsoy3o.png)

![uart3_serial.png](https://oss-club.rt-thread.org/uploads/201907/31/110618jfdzffdwf7fdffd7.png)

![menuconfig.png](https://oss-club.rt-thread.org/uploads/201907/31/110619cee0eopgm4ew2opx.png)