请使用RT-Thread studio开发程序，STM32F401RCT6PA1 TXD、PA0 RXD与ESP8266连接，使用AT指令连接WIFI

1. 首先，在RT-Thread Studio中新建一个STM32F401RCT6PA1的工程。
2. 将TXD和RXD引脚连接到ESP8266的TX和RX引脚上。
3. 在工程中添加ESP8266的AT指令驱动，可以使用RT-Thread Studio提供的AT指令驱动模板进行开发。
4. 在应用程序中使用AT指令连接WIFI，可以参考以下代码：

#include <rtthread.h>
#include <rtdevice.h>
#include <at.h>

#define WIFI_SSID "your_wifi_ssid"
#define WIFI_PASSWORD "your_wifi_password"

static int wifi_connect(void)
{
    char cmd[64];
    rt_uint32_t timeout = 10000;
    rt_size_t recv_len;
    char recv_buf[128];
    rt_uint32_t start_time, end_time;
    rt_device_t at_dev;

    /* 获取AT设备 */
    at_dev = rt_device_find("at");
    if (at_dev == RT_NULL)
    {
        rt_kprintf("AT device not found!\n");
        return -RT_ERROR;
    }

    /* 等待AT设备准备好 */
    if (rt_device_open(at_dev, RT_DEVICE_OFLAG_RDWR) != RT_EOK)
    {
        rt_kprintf("Open AT device failed!\n");
        return -RT_ERROR;
    }

    /* 检查模块是否正常 */
    rt_sprintf(cmd, "AT\r\n");
    if (at_send_wait_resp(at_dev, cmd, "OK", recv_buf, sizeof(recv_buf), &recv_len, timeout) != RT_EOK)
    {
        rt_kprintf("AT command error!\n");
        return -RT_ERROR;
    }

    /* 设置WIFI连接参数 */
    rt_sprintf(cmd, "AT+CWJAP=\"%s\",\"%s\"\r\n", WIFI_SSID, WIFI_PASSWORD);
    if (at_send_wait_resp(at_dev, cmd, "OK", recv_buf, sizeof(recv_buf), &recv_len, timeout) != RT_EOK)
    {
        rt_kprintf("Connect to WIFI failed!\n");
        return -RT_ERROR;
    }

    /* 检查WIFI连接状态 */
    start_time = rt_tick_get();
    while (1)
    {
        rt_sprintf(cmd, "AT+CWJAP?\r\n");
        if (at_send_wait_resp(at_dev, cmd, "+CWJAP:\"%s\"", recv_buf, sizeof(recv_buf), &recv_len, timeout) == RT_EOK)
        {
            rt_kprintf("Connect to WIFI success!\n");
            break;
        }

        end_time = rt_tick_get();
        if ((end_time - start_time) > (timeout / RT_TICK_PER_SECOND))
        {
            rt_kprintf("Connect to WIFI timeout!\n");
            return -RT_ERROR;
        }
    }

    return RT_EOK;
}

int main(void)
{
    wifi_connect();

    return 0;
}

5. 编译并下载程序到STM32F401RCT6PA1开发板中，程序将自动连接到指定的WIFI网络。