[chirp_devel] Getting copy of written serial data upon read

[kc9uum]

Ahh, I see, thanks! I was thinking of doing something like

indata=serial.read(1)
while indata != "?" or indata != "G"
    data += indata

in the download function. I'm not sure if that's proper Python grammar, but
you get the idea. Could be done with if as well, but I think your
echo_write suggestion is better.


On Mon, Apr 29, 2013 at 5:13 PM, Dan Smith <dsmith at danplanet.com> wrote:

> > I'm working on adding support for a new radio, the Ritron RTX-450.
> > It's a commercial radio, but with a bit of VCO tinkering works in the
> > ham bands.
>
> Cool!
>
> > I started with template.py, and use uv5r.py as a reference, since I
> > have one of those as well. So far, I've mapped out the memory and
> > established communication with the radio, but I'm having a problem
> > when I read the data.  To establish communication, I first send a
> > series of "?", followed by a "G". As soon as the radio receives the
> > G, it starts sending data. What's happening in chirp, though, is when
> > I do the serial.read(1), I'm getting the sent data back and then the
> > radio data, as if the buffer doesn't clear. This uses an Icom OPC-478
> > style cable, where RX and TX are simply wire-OR'd together, so that
> > does make sense. I should mention that this cable works fine with the
> > OE software. Do I just need to look for the sent string in the
> > response and filter it out, or is there a better way to handle this?
> > I tried inserting serial.flush() after serial.write("G"), but when
> > stepping through the program that seemed to do nothing.
>
> Yeah, so those sorts of cables "echo" because of the unified TX/RX
> line. So, the best way to hand that is something like:
>
> def _echo_write(radio, data):
>     radio.pipe.write(data)
>     radio.pipe.read(len(data))
>
> and use _echo_write(radio, "foo") instead of radio.pipe.write("foo") in
> your communication. Various permutations of the above are used in
> drivers having to deal with this sort of behavior.
>
> --
> Dan Smith
> www.danplanet.com
> KK7DS
>
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