[OpenTRV-dev] Help getting serial connection to Radbot

[Robert May]

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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