<div dir="ltr">Hi Michael,<div><br></div><div>The change looks helpful, thanks. I'll try it during the course of the day.</div><div><br></div><div>It does prompt me to ask a question that I had - On the i3, if you do something like send a lock from the key or the Connected Drive APP then the OBD-II comes alive but goes asleep again in less than a minute.</div><div><br></div><div>if I have a PID that I poll infrequently - say every 120 seconds. What happens in this case? Would they be seen as "overdue" when the bus comes alive and polled immediately, or is it a matter of luck if the 120th tick arrives at a time when the bus is alive?<br></div><div><br></div><div>If the latter I need to poll even things like the VIN every 10 seconds to make sure I get it before the bus goes to sleep again.</div><div><br></div><div>Thanks,</div><div>Steve</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 7 Jan 2021 at 18:22, Michael Balzer <<a href="mailto:dexter@expeedo.de">dexter@expeedo.de</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>
Everyone,<br>
<br>
please pull & test the new "can-txfail-fix" branch. It's up to
date and includes the BMW i3 code already.<br>
<br>
I need to get feedback from users of both can1 (esp32can) &
can2/3/4 (mcp2515), as changes had to be made to both drivers.<br>
<br>
I'll quote from my commit: <br>
<a href="https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/commit/c94592a11ad2c989e65313d23a8876cf38787d70" target="_blank">https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/commit/c94592a11ad2c989e65313d23a8876cf38787d70</a><br>
<br>
<div style="box-sizing:border-box;display:block;color:rgb(36,41,46);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">
<pre style="box-sizing:border-box;font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,monospace;font-size:13px;margin-top:10px;margin-bottom:0px;max-width:100%;line-height:1.45;white-space:pre-wrap;overflow:visible">Design goals:
- any TX can either fail or succeed, the result state is terminal
- the respective TX callback is called exactly once
- transmissions fail on reaching the error-passive bus state
and on message/bus errors while in error-passive state
- a failed TX will be aborted (no retries after bus recovery),
i.e. will be retried at most 128 times (in error-active phase)
- reduce excessive CAN error logging
- reduce excessive interrupt load with switched-off buses
This results in the application being able to reliably detect a
switched-off vehicle bus by the TX callback's success indicator.
It also results in frames no longer being held in the TX buffer
or added to the TX queue when the bus is switched off. The
application can now rely on getting a clean bus state on every
reconnect, without any queued old frames to be sent automatically.
Secondary benefit from aborting the transmission is, the module
doesn't need to handle the load from the continuously triggered
CAN error interrupts by retransmission attempts in error-passive
state.</pre>
</div>
<br>
Reason for this was a) Steve's question on aborting transmissions /
flushing the queue and b) my new car now also switching off the bus,
with the annoying effect of a frozen can1 every 2-3 days, needing to
reboot the module. I'm not sure yet if the freeze issue is solved,
but I haven't had it since running these changes on my module.<br>
<br>
The other issue of the transceivers resending frames queued long ago
may have caused all sorts of strange & unrepeatable issues. I
remember the VW crew having problems that fell into this category.<br>
<br>
I've verified the new MCP2515 implementation only on my workbench
(with an Arduino as the CAN tester), so real life tests are
necessary.<br>
<br>
Thanks,<br>
Michael<br>
<br>
<pre cols="72">--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26</pre>
</div>
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