AT Socket中的串口问题，原因已经找到，usart.c问题，如下

发布于 2018-12-05 18:16:08 浏览：3277 订阅该版

* 本帖最后由 fengye 于 2018-12-6 19:45 编辑 *

1，根据AT命令客户端应用笔记配置工程，测试AT Socket，bsp用的是stm32f10x，编译下载后串口打印信息如下：
 \ | /
- RT -     Thread Operating System
 / | \     3.1.1 build Dec  5 2018
 2006 - 2018 Copyright by rt-thread team
[32m[I/SAL_SOC] Socket Abstraction Layer initialize success.[0m
[32m[I/at.clnt] AT client(V1.2.0) on device uart3 initialize success.[0m
msh >[31m[E/at.clnt] execute command (AT+RST) failed![0m
[31m[E/at.esp8266] RT AT send commands(AT+RST) error![0m
[31m[E/at.esp8266] AT network initialize failed (-1)![0m

,2，用串口监测是STM32串口3与8266通信，发现STM32指令的第一个字符没有发出来，如图：
![rst1.png](/uploads/201812/05/173458xbas3zz40z814n6z.png),

3，于是把AT Socket关闭，写了一个测试线程，把如下：
void test_thread_entry(void* parameter)
{    
    rt_uint8_t uart_rx_data;

/* 打开串口 */
    if (uart_open("uart3") != RT_EOK)
    {
        rt_kprintf("uart open error.<br>");
         while (1)
         {
            rt_thread_delay(10);
         }
    }

/* 单个字符写 */
    uart_putchar('2');
    uart_putchar('0');
    uart_putchar('1');
    uart_putchar('8');
    uart_putstring(" <br>");
    /* 写字符串 */
    uart_putstring("Hello RT-Thread! <br>");

while (1)
    {   
        /* 读数据 */
        uart_rx_data = uart_getchar();
        /* 错位 */
        uart_rx_data = uart_rx_data + 1;
        /* 输出 */
        uart_putchar(uart_rx_data);

}            
}

打印结果如图：发现第一个字符没有发出来
![uart.png](/uploads/201812/05/175436q2622szq2da21slv.png)

4，想起之前跑裸机时串口也遇到过这个问题，原因是配置完串口时，没有清发送完成标志，
于是在usart.c中的stm32_configure()函数中，加入
  /* CPU的小缺陷：串口配置好，如果直接Send，则第1个字节发送不出去 */
  USART_ClearFlag(uart->uart_device, USART_FLAG_TC);     /* 清发送完成标志，Transmission Complete flag */

static rt_err_t stm32_configure(struct rt_serial_device *serial, struct serial_configure *cfg)
{
    struct stm32_uart* uart;
    USART_InitTypeDef USART_InitStructure;

RT_ASSERT(serial != RT_NULL);
    RT_ASSERT(cfg != RT_NULL);

uart = (struct stm32_uart *)serial->parent.user_data;

USART_InitStructure.USART_BaudRate = cfg->baud_rate;

if (cfg->data_bits == DATA_BITS_8){
        USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    } else if (cfg->data_bits == DATA_BITS_9) {
        USART_InitStructure.USART_WordLength = USART_WordLength_9b;
    }

if (cfg->stop_bits == STOP_BITS_1){
        USART_InitStructure.USART_StopBits = USART_StopBits_1;
    } else if (cfg->stop_bits == STOP_BITS_2){
        USART_InitStructure.USART_StopBits = USART_StopBits_2;
    }

if (cfg->parity == PARITY_NONE){
        USART_InitStructure.USART_Parity = USART_Parity_No;
    } else if (cfg->parity == PARITY_ODD) {
        USART_InitStructure.USART_Parity = USART_Parity_Odd;
    } else if (cfg->parity == PARITY_EVEN) {
        USART_InitStructure.USART_Parity = USART_Parity_Even;
    }

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(uart->uart_device, &USART_InitStructure);

/* CPU的小缺陷：串口配置好，如果直接Send，则第1个字节发送不出去 */
        USART_ClearFlag(uart->uart_device, USART_FLAG_TC);     /* 清发送完成标志，Transmission Complete flag */
        
    /* Enable USART */
    USART_Cmd(uart->uart_device, ENABLE);

return RT_EOK;
}

然后先通过串口先测试效果，如下图：
![usat.png](/uploads/201812/05/175859derc0qccdc7tzt17.png)

5，开启AT Socket功能，发现还是不行，第一个字母发不出来，是加的位置不对吗？
6，后面我在发送第一条指令时，多加一个字符，代码如下：
static void esp8266_init_thread_entry(void *parameter)
{
    at_response_t resp = RT_NULL;
    rt_err_t result = RT_EOK;
    rt_size_t i;

resp = at_create_resp(128, 0, rt_tick_from_millisecond(5000));
    if (!resp)
    {
        LOG_E("No memory for response structure!");
        result = -RT_ENOMEM;
        goto __exit;
    }

rt_thread_delay(rt_tick_from_millisecond(5000));
    /* reset module */
    AT_SEND_CMD(resp, "AAT+RST");
    /* reset waiting delay */
    rt_thread_delay(rt_tick_from_millisecond(1000));
    /* disable echo */
    AT_SEND_CMD(resp, "ATE0");
    /* set current mode to Wi-Fi station */
    AT_SEND_CMD(resp, "AT+CWMODE=1");
    /* get module version */
    AT_SEND_CMD(resp, "AT+GMR");

模块就能正常连上网络，如图：
![succ.png](/uploads/201812/05/181212e6coq0o3zphl99zh.png)
有谁遇到过类似的问题，到底问题在哪里？看了一天代码了，硬是不知道到改哪里！望各位指点指点

10 个回答

armink 2018-12-06

这家伙很懒，什么也没写！

来一颗糖 2018-12-06

这家伙很懒，什么也没写！

fengye 2018-12-06

这家伙很懒，什么也没写！

fengye 2018-12-06

这家伙很懒，什么也没写！

armink 2018-12-06

这家伙很懒，什么也没写！

fengye 2018-12-06

这家伙很懒，什么也没写！

[i=s] 本帖最后由 fengye 于 2018-12-6 18:08 编辑 [/i]

总结：stm32f10x的BSP串口问题引起的，修改地方，usart.c中
1：static rt_err_t stm32_configure(struct rt_serial_device *serial, struct serial_configure *cfg)函数
     添加/* 清发送完成标志，Transmission Complete flag */
static rt_err_t stm32_configure(struct rt_serial_device *serial, struct serial_configure *cfg)
{
    struct stm32_uart* uart;
    USART_InitTypeDef USART_InitStructure;

RT_ASSERT(serial != RT_NULL);
    RT_ASSERT(cfg != RT_NULL);

uart = (struct stm32_uart *)serial->parent.user_data;

USART_InitStructure.USART_BaudRate = cfg->baud_rate;

return RT_EOK;
}

2：static int stm32_putc(struct rt_serial_device *serial, char c)函数
     添加/* 清发送完成标志，Transmission Complete flag */
static int stm32_putc(struct rt_serial_device *serial, char c)
{
    struct stm32_uart* uart;

RT_ASSERT(serial != RT_NULL);
    uart = (struct stm32_uart *)serial->parent.user_data;

if (serial->parent.open_flag & RT_DEVICE_FLAG_INT_TX)
    {
        if (!(uart->uart_device->SR & USART_FLAG_TXE))
        {
            USART_ITConfig(uart->uart_device, USART_IT_TC, ENABLE);
            return -1;
        }
        uart->uart_device->DR = c;
        USART_ITConfig(uart->uart_device, USART_IT_TC, ENABLE);
    }
    else
    {
        /* CPU的小缺陷：串口配置好，如果直接Send，则第1个字节发送不出去 */
        USART_ClearFlag(uart->uart_device,USART_FLAG_TC);

uart->uart_device->DR = c;
        while (!(uart->uart_device->SR & USART_FLAG_TC));
    }

return 1;
}
结贴