TPMS renault Flag and Unknown fileds expériment

[benppppp]

Hello,
For information, I performed some test on TPMS renault to understand the fields flags and Unknown.
The studied sensor are recognised as:
src/devices/tpms_renault.c
Flags
I tried to vary the voltage supply: I removed the battery and vary the volatage with arduino PWM+RC filter (1000µF+220ohms).
Test performed on the renault TPMS E24 10R-041328
With a switch OFF/ON at 3.28V, flags is 35 then 31 after one minute then 30 after one more minute.
The flags don't vary with voltage between 2.7V and 3.3V
The sensor don't transmit any more data at 2.6V
Unknown
On the sensor E24 10R-041328 (mount on Clio4), Unknown is always FFFF
On sensor 407004CB0B(mount on Zoe 2), Unknown is 9409 for stable pressure, 8C09 for pressure decrease and sometime 9449 for ?????
The 9409 is necessary for Zoé2: I tried to mount E24 10R-041328 on Zoé2 and it don't work.

It is possible to transcode from E24 10R-041328 to 407004CB0B with CC1101+Arduino. I performed this here:
https://forum.arduino.cc/t/tpms-transcoder-for-renault-zoe2-with-cc1101-and-arduino-nano/1363151/8

Maybe, It should be useful to change the comments in src/devices/tpms_renault.c

[zuckschwerdt]

Very interesting post about the transcoding, thanks!

Then flags contains likely some initialization/startup indication? So far we have seen (hex) 30 32 34 36 -- you are also seeing 30 and 34 but with the last bit set, i.e. 31 and 35. The last bit might be "startup" or "reset" for 2 minutes.

The Zoe2 9409 for stable pressure, 8C09 for pressure decrease and 9449 for something else is a mystery.
Is it only ever those values? So many bits for just three states! But there might be a bit for "pressure alert" in there, BitBench -- 4th/5th bit for normal/alert and then 10th for the other state.

I'll add these findings as comment to the decoder: 76936cb