[Ovmsdev] What happened to TPMS?

Craig Leres leres at xse.com
Wed Apr 22 12:11:57 HKT 2020

On 2020-04-21 20:21, Mark Webb-Johnson wrote:
> I think the issue you have is that after a firmware update the module 
> will reboot. That will mean it will lose the metrics for TPMS.
> Those metrics won’t come back until the car has been driven.
> I don’t see a simple solution. We could address it in v2 protocol by not 
> sending the tpms message unless the metrics are defined, but that might 
> still mess up the stale indicator. That wouldn’t affect the individual 
> metrics and v3 protocol we are trying to move to for the future.
> There is a small amount of RTC ram that is retained through a reboot. 
> Perhaps we could have a mechanism to save+restore certain metrics there? 
> But not at all simple.

I think the same situation exists for soc, if you decide to go with the 
"don't send when undefined" it would be good to change it too.

I just did some testing and I guess the V3 protocol already works this way.


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