[OpenTRV-dev] Help getting serial connection to Radbot

[Robert May]

Thanks Damon, Christoph.

I already moved to soldering my connections to eliminate that issue.

I can see the TX LED flash on my dongle when I hit <return>, and if I swap
the tx/rx connections so I have tx on dongle to tx on Radbot and rx on
dongle to rx on Radbot then after I hit <return> I see the rx led on the
dongle flash approx. every 2 seconds for a while - so I *think* I'm waking
it up.    This feels wrong, but past experience tells me that there is
sometimes confusion over how rx and tx pins are marked.

But I see nothing in my terminal.  I've shortened the wires as much as I
can, and I'm sure that my grounds are OK

Can you expand on what you mean by "perhaps one of the devices doesn’t like
the 3.0V supply"?

Here's a couple of pictures
https://www.dropbox.com/s/s8jdv6j9a4covw3/Photo%2014-02-2021%2C%2020%2041%2054.jpg?dl=0
https://www.dropbox.com/s/sp819pw2ds1lf73/Photo%2014-02-2021%2C%2020%2042%2011.jpg?dl=0
(not a good shot, but I'm sure the pins and +ve terminals are not touching)

Any other ideas?  I've been staring at this all day and can't see what's
wrong.

Rob.


On Sun, 14 Feb 2021 at 19:33, Christoph M. Wintersteiger <
christoph at winterstiger.at> wrote:

> Hi Rob,
>
>
>
> That’s great, you’ve got very far in a very short amount of time!
>
>
>
> It sounds like you’re “holding” the wires on – just solder them on if you
> have a soldering iron around, it’s easy enough to take them back off after
> the operation.
>
>
>
> I can imagine that there’s a ground potential problem and perhaps one of
> the devices doesn’t like the 3.0V supply. The Radbot takes very little
> power and I was able to simply power it from my USB-serial adapter, but
> that depends on the adapter of course. Alternatively, the RPi also has a
> 3.3V supply (and 5.0V too) and it has a serial port right next to the
> supply pins too, so if you have a few breadboard wires around, that would
> be a simple and quick alternative.
>
>
>
> Cheers,
>
> Christoph
>
>
>
> *From:* OpenTRV-dev <opentrv-dev-bounces at lists.opentrv.org.uk> *On Behalf
> Of *Robert May
> *Sent:* Sunday, 14 February, 2021 18:24
> *To:* Closed list for developer discussions <
> opentrv-dev at lists.opentrv.org.uk>
> *Subject:* [OpenTRV-dev] Help getting serial connection to Radbot
>
>
>
> I've finally found time to unbox my Radbots.   The plan is to build a
> combined stats hub and boiler controller based on a RPi.
>
>
>
> I've successfully compiled the code Christoph shared (
> https://github.com/wintersteiger/wlmcd) and used to to show the one
> Radbot I've powered up transmits and that I can receive the frames using a
> CC1101/RPi combination.  Of course the decryption fails as I've yet to set
> a decryption key.
>
>
>
> I'm struggling to get a connection over the serial port to the Radbot.
> I'm trying to follow the instructions shared by Tristan (
> https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs) but I
> can't seem to get any comms over the serial port.
>
>
>
> I've opened up my radbot to get better access to the pads.
>
> I'm powering the Radbot from a bench power supply at 3.0V
>
> I've got a USB serial dongle operating at 3.3V logic, grounded to the -ve
> supply.
>
> I think I'm hold the rx/tx lines on the pads (tx from my dongle to rx on
> the radbot and rx on the dongle to tx on the Radbot), but I get nothing
> from 'screen' that I'm using for my terminal.
>
>
>
> As far as I know I'm using 4800baud, 8-N-1 (screen /dev/ttyUSB0 4800),
> which I believ to be the expected settings?
>
>
>
> Can anyone see anything that I'm doing wrong or give me a pointer to
> things that I can try. ?
>
>
>
> Thanks,
>
> Rob.
>
>
>
>
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>
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