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<p>There is a comment in the FreeBSD device driver source for the
CH340 which says something along the lines of:</p>
<p>"This is a driver for the WinChipHead CH340. The worst USB to
serial converter chip in the world."</p>
<p>Having had roughly the same experience as the person who
eventually designed this:</p>
<p><a class="moz-txt-link-freetext" href="https://uart-adapter.com/#why">https://uart-adapter.com/#why</a></p>
<p>... I eventually gave up and bought one, and it's paid for itself
over the past couple of years in saved time/doubt when debugging
stuff.</p>
<p>It uses a genuine (not pirate/clone) chip from Glasgow-based
FTDI.</p>
<p>A little on the (very common) fakes here:</p>
<p><a class="moz-txt-link-freetext" href="https://www.voltlog.com/identifying-replacing-a-fake-ftdi-ft232r-chip-voltlog-314/">https://www.voltlog.com/identifying-replacing-a-fake-ftdi-ft232r-chip-voltlog-314/</a></p>
<p>If you don't need the galvanic isolation and wide voltage range
of the µart, then you can get basic 3.3v / 5v FTDI based adapters
from RS or Farnell etc.<br>
</p>
<p><a class="moz-txt-link-freetext" href="https://uk.farnell.com/ftdi/lc234x/eval-brd-usb-to-uart-interface/dp/2753006">https://uk.farnell.com/ftdi/lc234x/eval-brd-usb-to-uart-interface/dp/2753006</a></p>
<p>HTH!<br>
</p>
<p>Cheers,</p>
<p>Tim.<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 14/02/2021 23:25, Robert May wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAK=sgrvsZod0SO10LdZ7dQnfYb8vhgu798sa7yWHqakWrZBjSA@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">Regardless of what else changed I can't make it
work with my (cheap) CH430 USB dongle (similar to this one: <a
href="https://www.ebay.co.uk/itm/3-3V-5V-Serial-Adapter-Module-CH340G-USB-to-TTL-6-Pin-UART-Adapter/192935577926?hash=item2cebdb4946:g:RFsAAOSwyXNZ-mJr"
moz-do-not-send="true">https://www.ebay.co.uk/itm/3-3V-5V-Serial-Adapter-Module-CH340G-USB-to-TTL-6-Pin-UART-Adapter/192935577926?hash=item2cebdb4946:g:RFsAAOSwyXNZ-mJr</a>).
It works fine with the PI's built in serial port, so no
actual dongle needed at all.
<div><br>
</div>
<div>To use the built in serial port you need to stop the PI
using it for boot messages and attaching a terminal to it:</div>
<div>sudo raspi-config; Select option 3 Interface Options, and
then Option P6 Serial port; Answer 'no' to the question
"would you like a login shell to be accessible over serial?",
and 'yes' to "Would you like the serial port hardware to be
enabled", and then reboot.</div>
<div><br>
</div>
<div>Then connect Physical pin 8 (TxD) to TX pad on Radbot and
physical pin 10 (RxD) to RX pad on radbot. COnnect one of
the ground pins (e.g. physical pin 6) to the -ve terminal of
the radbot. and start a terminal on /dev/ttyAMA0</div>
<div><br>
</div>
<div>Either screen (if you have it installed): screen
/dev/ttyAMA0 4800. (Ctl-A k to kill the session and exit)</div>
<div>or microcom (installed in base image): busybox microcom -s
4800 /dev/ttyAMA0 (Ctrl-X to exit)</div>
<div>
<div><br>
</div>
<div>If it's safe to power the Radbot from 5V then it could be
powered from the PI, but not from the 3.3V rail if the motor
unit's attached (usually OK to get at least 300mA from the
5V rail, but only 50mA allowed from the 3.3v rail - source: <a
href="https://www.circuits.dk/everything-about-raspberry-gpio/#:~:text=The%20total%20maximum%20recommended%20current,the%20rest%20of%20the%20board"
moz-do-not-send="true">https://www.circuits.dk/everything-about-raspberry-gpio/#:~:text=The%20total%20maximum%20recommended%20current,the%20rest%20of%20the%20board</a>.
). If my memory serves me I was seeing about 160mA draw
when the motor was running.</div>
</div>
<div><br>
</div>
<div>Rob.</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, 14 Feb 2021 at 23:01,
Tristan Keen <<a href="mailto:tristan.keen@gmail.com"
target="_blank" moz-do-not-send="true">tristan.keen@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">Glad to hear you got there!
<div><br>
</div>
<div> My USB/Serial cable (link in Part List wiki page) was
outputting 4.9 V open circuit from the "power"
connections, so I presume it was connected to the USB main
power output. Originally I tried powering the Radbot via
a couple of low value (82 Ohm) resistors as I was a bit
nervous of driving it at the higher than expected voltage,
but couldn't connect reliably. After checking the Atmel
328P's datasheet, which suggests a 2.7 - 6V range, I
removed the resistors and tried again - it worked.
Voltage dropped to 4.4 volts or so when the motor came on
during its initial valve cycling though.</div>
<div>
<div><br>
</div>
<div>So far all four appear to be unharmed...</div>
</div>
<div><br>
</div>
<div>Tristan.</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, 14 Feb 2021 at
22:26, Robert May <<a
href="mailto:rob@themayfamily.me.uk" target="_blank"
moz-do-not-send="true">rob@themayfamily.me.uk</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div dir="ltr">Thanks all. I'm there (or at least I
think I am).
<div><br>
<div>I changed a number of things - the voltage I'm
driving the Radbot (now at 3.3v), I remade my
solder connections and replaced the
wires/connectors as I think one of the dupont
connectors was loose, and I moved to using the
built in serial port of the PI (/dev/AMA0). I'll
see if I can work out which of these was actually
the culprit.</div>
</div>
<div><br>
</div>
<div>Out of interest, what is the max voltage that is
safe to run the Radbot. If I understand this page
correctly (<a
href="https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs"
target="_blank" moz-do-not-send="true">https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs</a>)
then it is suggesting powering it at 5V (direct from
the USB port)</div>
<div><br>
</div>
<div>Onwards.</div>
<div>Rob.</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, 14 Feb 2021
at 21:45, Damon Hart-Davis <<a
href="mailto:dhd@exnet.com" target="_blank"
moz-do-not-send="true">dhd@exnet.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px
0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>Hi,
<div><br>
</div>
<div>1) FWIW, when I am powering remotely, eg to
reflash, I tend to run at 3.6V.</div>
<div><br>
</div>
<div>2) Yes, I think that we label our TX and RX
the ‘wrong’ way round and have confused
ourselves from time to time. Almost certainly
an early error or at least bad choice by me,
reinforced by my trying to then be consistent
across schematics.</div>
<div><br>
</div>
<div>3) FWIW I use a FTDI TTL-232R-3V3 to talk to
Radbots.</div>
<div><br>
</div>
<div>Rgds</div>
<div><br>
</div>
<div>Damon<br>
<div><br>
<blockquote type="cite">
<div>On 14 Feb 2021, at 20:52, Robert May
<<a
href="mailto:rob@themayfamily.me.uk"
target="_blank" moz-do-not-send="true">rob@themayfamily.me.uk</a>>
wrote:</div>
<br>
<div>
<div dir="ltr">Thanks Damon, Christoph.
<div><br>
</div>
<div>I already moved to soldering my
connections to eliminate that issue.</div>
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>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</div>
<div><br>
</div>
<div>Can you expand on what you mean by
"perhaps one of the devices doesn’t
like the 3.0V supply"?</div>
<div><br>
</div>
<div>Here's a couple of pictures</div>
<div><a
href="https://www.dropbox.com/s/s8jdv6j9a4covw3/Photo%2014-02-2021%2C%2020%2041%2054.jpg?dl=0"
target="_blank"
moz-do-not-send="true">https://www.dropbox.com/s/s8jdv6j9a4covw3/Photo%2014-02-2021%2C%2020%2041%2054.jpg?dl=0</a><br>
</div>
<div><a
href="https://www.dropbox.com/s/sp819pw2ds1lf73/Photo%2014-02-2021%2C%2020%2042%2011.jpg?dl=0"
target="_blank"
moz-do-not-send="true">https://www.dropbox.com/s/sp819pw2ds1lf73/Photo%2014-02-2021%2C%2020%2042%2011.jpg?dl=0</a>
(not a good shot, but I'm sure the
pins and +ve terminals are not
touching)<br>
</div>
<div><br>
</div>
<div>Any other ideas? I've been staring
at this all day and can't see what's
wrong.</div>
<div><br>
</div>
<div>Rob.</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On
Sun, 14 Feb 2021 at 19:33, Christoph
M. Wintersteiger <<a
href="mailto:christoph@winterstiger.at"
target="_blank"
moz-do-not-send="true">christoph@winterstiger.at</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div lang="EN-US">
<div>
<p class="MsoNormal">Hi Rob,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">That’s great,
you’ve got very far in a very
short amount of time! </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">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.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">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.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Cheers,</p>
<p class="MsoNormal">Christoph</p>
<p class="MsoNormal"> </p>
<div
style="border-right:none;border-bottom:none;border-left:none;border-top:1pt
solid
rgb(225,225,225);padding:3pt 0in
0in">
<p class="MsoNormal"><b>From:</b>
OpenTRV-dev <<a
href="mailto:opentrv-dev-bounces@lists.opentrv.org.uk"
target="_blank"
moz-do-not-send="true">opentrv-dev-bounces@lists.opentrv.org.uk</a>>
<b>On Behalf Of </b>Robert
May<br>
<b>Sent:</b> Sunday, 14
February, 2021 18:24<br>
<b>To:</b> Closed list for
developer discussions <<a
href="mailto:opentrv-dev@lists.opentrv.org.uk"
target="_blank"
moz-do-not-send="true">opentrv-dev@lists.opentrv.org.uk</a>><br>
<b>Subject:</b> [OpenTRV-dev]
Help getting serial connection
to Radbot</p>
</div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal">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.</p>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">I've
successfully compiled the
code Christoph shared (<a
href="https://github.com/wintersteiger/wlmcd"
target="_blank"
moz-do-not-send="true">https://github.com/wintersteiger/wlmcd</a>)
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.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">I'm
struggling to get a
connection over the serial
port to the Radbot. I'm
trying to follow the
instructions shared by
Tristan (<a
href="https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs"
target="_blank"
moz-do-not-send="true">https://github.com/tyrken/heatmon/wiki/Reprogramming-Radbot-TRVs</a>)
but I can't seem to get any
comms over the serial port.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">I've
opened up my radbot to get
better access to the pads.</p>
</div>
<div>
<p class="MsoNormal">I'm
powering the Radbot from a
bench power supply at 3.0V</p>
</div>
<div>
<p class="MsoNormal">I've got
a USB serial dongle
operating at 3.3V logic,
grounded to the -ve supply.</p>
<div>
<p class="MsoNormal">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.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">As far
as I know I'm using
4800baud, 8-N-1 (screen
/dev/ttyUSB0 4800), which
I believ to be the
expected settings?</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Can
anyone see anything that
I'm doing wrong or give me
a pointer to things that I
can try. ?</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Thanks,</p>
</div>
<div>
<p class="MsoNormal">Rob.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
</div>
</div>
</div>
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