为什么我可以串口通信发送数据，但是接收不到数据？波特率和中英文都注意了，串口扩展版蓝灯闪了一下就灭了？

[2gs6]

import time
from pyb import UART

Always pass UART 3 for the UART number for your OpenMV Cam.

The second argument is the UART baud rate. For a more advanced UART control

example see the BLE-Shield driver.

uart = UART(3, 9600, timeout_char=1000)

while(True):

if uart.any():
    a=uart.readline()
    print(a)

[kidswong999]

https://singtown.com/learn/50240/

是按照视频步骤操作的吗？