Re: How to snif full-duplex UART protocol between two nodes

From	Grant Edwards <invalid@invalid.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: How to snif full-duplex UART protocol between two nodes
Date	2023-02-20 22:18 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<tt0rk6$68m$1@reader2.panix.com> (permalink)
References	<tsvh99$mpm3$1@dont-email.me>

Show all headers | View raw

On 2023-02-20, pozz <pozzugno@gmail.com> wrote:

> Many times I need to snif and log on a file the activity between two 
> nodes that talk over a full-duplex UART (separate TX and RX lines).

If you have to do that "many times", then buy a serial protocol
analyzer widget that has hardware that has two capture ports and
timestamps every bit/byte.

I have and older version of this and it works brilliantly:

    https://www.iftools.com/analyzer/msb-rs232/index.en.php

There are similar but cheaper products from other vendors, but if it's
something you need to do often, then it's worth a few hundred
dollars/euros to get a decent one.

> Just an example, consider a host MCU that talks with a modem through AT 
> commands. It's a half-duplex protocol because the MCU sends the AT 
> command and the modem replies. However the modem is able to send URC 
> messages that can be emitted at any time.
>
> I think the better approach is to use two different UART/USB converters, 
> one for each signal (of course, both signals goes to the RX inputs of 
> the converters).

The latency/buffer in the USB adpaters is awful. Spend some money and
by a real serial analyzer.

> What about the sofware on the PC? It should open two serial ports and 
> monitors both of them, joining together the messages on a single file. A 
> great feature would be to have a timestamp for each message, where a 
> message is "\r\n" delimited.

Thread

How to snif full-duplex UART protocol between two nodes pozz <pozzugno@gmail.com> - 2023-02-20 11:16 +0100
  Re: How to snif full-duplex UART protocol between two nodes Don Y <blockedofcourse@foo.invalid> - 2023-02-20 04:17 -0700
  Re: How to snif full-duplex UART protocol between two nodes Theo <theom+news@chiark.greenend.org.uk> - 2023-02-20 12:23 +0000
  Re: How to snif full-duplex UART protocol between two nodes Richard Damon <Richard@Damon-Family.org> - 2023-02-20 07:59 -0500
  Re: How to snif full-duplex UART protocol between two nodes Paul Rubin <no.email@nospam.invalid> - 2023-02-20 13:52 -0800
    Re: How to snif full-duplex UART protocol between two nodes pozz <pozzugno@gmail.com> - 2023-02-21 10:59 +0100
      Re: How to snif full-duplex UART protocol between two nodes Don Y <blockedofcourse@foo.invalid> - 2023-02-21 04:11 -0700
        Re: How to snif full-duplex UART protocol between two nodes Theo <theom+news@chiark.greenend.org.uk> - 2023-02-22 11:33 +0000
          Re: How to snif full-duplex UART protocol between two nodes Don Y <blockedofcourse@foo.invalid> - 2023-02-22 05:08 -0700
    Re: How to snif full-duplex UART protocol between two nodes Rick C <gnuarm.deletethisbit@gmail.com> - 2023-02-21 14:05 -0800
      Re: How to snif full-duplex UART protocol between two nodes Paul Rubin <no.email@nospam.invalid> - 2023-02-21 16:55 -0800
        Re: How to snif full-duplex UART protocol between two nodes Brian Cockburn <brian.cockburn.1959@gmail.com> - 2023-04-22 07:03 -0700
  Re: How to snif full-duplex UART protocol between two nodes Grant Edwards <invalid@invalid.invalid> - 2023-02-20 22:18 +0000
  Re: How to snif full-duplex UART protocol between two nodes Clifford Heath <no.spam@please.net> - 2023-02-21 09:58 +1100
  Re: How to snif full-duplex UART protocol between two nodes Andrew Smallshaw <andrews@sdf.org> - 2023-02-21 07:05 +0000
  Re: How to snif full-duplex UART protocol between two nodes Andrew Smallshaw <andrews@sdf.org> - 2023-02-21 07:07 +0000

csiph-web