Serial Connector Software Interaction

Question

Suppose you want to offer an interface for other programmers, which allows them to write code like this:

# connect to remote Linux device >>> conn = myClass('/dev/ttyUSB0', 115200, '8N1') >>> conn.login('myname', 'mypass') >>> output = conn.command('ls -al') >>> print output total 3 drwxr-xr-x 49 myname myname 4096 Jun 21 15:13 . drwxr-xr-x 4 root root 4096 Mar 20 14:43 .. drwxr-xr-x 49 myname myname 1005 Jun 14 11:23 .vimrc >>> output2 = conn.command('cd ..') >>> print output2 >>> 

How could you implement it?

Current state

I first thought of pyserial , but it seems to treat the serial connection just as a file, similar to an object, and not like a terminal. I found from it the source code that pyserial itself uses termios , which at least seems to allow some terminal configuration options. But what structure allows terminal-like IO? I’m just a newbie in the whole world of embedded systems in general, but so far it seems to me that an IO terminal through a serial connection should be a normal everyday problem in this environment, and there should already be a structure that performs “hard work.” But so far then I could not find him.

Background

Currently, most people in my company are checking their topics for developing an embedded system manually. But we want to switch to a more automatic script with a lot of unittest like scripts. Since we already have an interface like UART for our embedded systems, I would like to give the authors of these test scripts the opportunity to write code more intuitively, since in any case they could interact with devices through a minicomputer or screen.

Answer 1

I would strongly consider using Twisted and projects using Twisted for Python projects talking to terminals. I saw a terminal screen scraper written in Twisted, and at least one telnet public client on GitHub - https://github.com/fjogstad/twisted-telnet-client .

I'm not sure what terminal interface you are trying to talk to, but at least here is an example of a terminal emulator in Twisted: https://launchpad.net/python-tvi955 .

The good thing about using an asynchronous structure like Twisted would be that you could test one test server at the same time on multiple virtual machines or physical machines.

Answer 2

DO NOT REQUEST A SPECIAL QUESTION, but most likely you found it on Google to get the following:

If you really want to interact with the serial i / f interface , try using: pyserial ( pip install pyserial ):

here is an example :

 import serial ser = serial.Serial( port='/dev/ttyUSB1', baudrate=9600, parity=serial.PARITY_ODD, stopbits=serial.STOPBITS_TWO, bytesize=serial.SEVENBITS ) ser.open() ser.write("bla bla" + '\r')