从ttyUSB0写入和读取，无法获得响应

问题描述

我对Linux tty的经验不是很丰富.我的环境是带有大量USB串行接口的Raspbian.

有效方法:

  stty -F/dev/ttyUSB0 38400cu -l/dev/ttyUSB0 -s 38400 

将

cu 转换为/dev/ttyUSB0 即可.我可以在300毫秒内将命令写入终端，并从另一个终端获得响应.

什么不起作用:在一个终端中

  echo"command">/dev/ttyUSB0 

在另一个终端中(在回显之前运行)

  cat</dev/ttyUSB0 

或

  tail -f/dev/ttyUSB0 

没有输出.

但是当我 echo"command">/dev/ttyUSB0 并打开 cu ，我可以看到回显的命令以及那里另一个终端的响应.

我想念什么?

最诚挚的问候

Sundypha

ps:我也尝试过，是一个小的python脚本:

 #！/usr/bin/python导入序列ser = serial.Serial('/dev/ttyUSB0'，38400，xonxoff = True)ser.open()如果 ser.isOpen():ser.write('命令')响应= ser.readline()列印回应ser.close() 

也不起作用，挂在ser.readline()

上

解决方案

如果在回显USB0设备时没有照顾到它，那么是的，您将不会看到它的输出，因为它已经消失了./p>

尝试类似的东西:

尾-f/dev/ttyUSB0

然后将内容回显到其中.

I'm not very experienced with the Linux tty's.My environment is a Raspbian with a prolific USB-serial.

What works:

stty -F /dev/ttyUSB0 38400
cu -l /dev/ttyUSB0 -s 38400

cu to /dev/ttyUSB0 works. I can write my commands to the terminal and get response from the other terminal within 300ms.

What not works:in one terminal

echo "command" > /dev/ttyUSB0

in another terminal (running before echo)

cat < /dev/ttyUSB0

or

tail -f /dev/ttyUSB0

there is no output.

But when i echo "command" > /dev/ttyUSB0 and have cu open, I can see the echoed command and the response from the other terminal there.

What am I missing?

best regards

Sundypha

ps: What I tried too, was a little python script:

#!/usr/bin/python
import serial
ser = serial.Serial('/dev/ttyUSB0', 38400, xonxoff=True)
ser.open()
if ser.isOpen():
    ser.write('command')
    response = ser.readline()
    print response
    ser.close()

did not work either, hangs on ser.readline()

解决方案

If you are not cat'ing the USB0 device as you echo to it, then yes, you will not see its output because it has been and gone.

try something like:

tail -f /dev/ttyUSB0

and then echo stuff into it.

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