Quote:
Originally Posted by RedErik
Hmmm, maybe that's not confusing at all. You could be entirely right saying that when unit boots or powers down is completely dependent of MCU and CAN messages, not 12V supply. That would mean we don't have to worry about connecting unit to appropriate terminal, rather figuring out MCU. Which in this case is even more complicated... no one has reverse engineered MCU and Chinese are slow (if at all) to implement user requests.
But this would make so much more sense than "primitive" voltage dependency. You could power up or down unit based on CAN messages form CAS (I believe this is how it's done in G series cars - with equivalent of CAS). That would also explain why unit powers up with bench supply and not necessarily when you connect that through CID connector. MCU must have a routine to check for presence of CAN network, if there is one - wait for message and act accordingly, if none detected - power up in "standalone mode".
I would need to go through some materials I have and TIS to verify what I just said, but it makes a very compelling argument. However if that is the case... there is nothing we can do now to benefit from that. We would need to pressure our sellers so they can talk to their engineers and these engineers than would have to... unbreakable chain of command. Someone it this thread suggested way back when if we could talk to the right people, do some crowdfunding, we could probably buy the source code for MCU and Android. I for one would throw in few quid for that.
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Perhaps we can achieve that be disconnecting CAN from head unit and connect CAN via CID.
In this case the unit will power up because it will detect can signal and power off when terminal 30g closes the circuit after 30 minutes.
But the screen will stay on for that time.
The appropriate way is to shut down the screen after you switch ignition off , light up screen when you press the volume knob in iDrive and stay alive for some time after .
the appropriate