Thread: Renault "Tuner List" Head Unit/CD changer hacking - Controls

Originally Posted by Ale

Here my schematic for both programming PIC and test with PC or HU.

Hey, this looks really simple. I thought the circuit would have been much more complicated !

I have corrected the link error but Track number is still blank.

Track number is blank ?
That's weird. Are you sending "PLAYING" frames once per second ?

Just for take a look this is a complete project developed with free MPLAB-IDE and the The CC5X compiler. And the free PIC programmer WINPIC.

Hey, this is really interesting. I had left PICs and microcontrollers more than 10 years ago but it's interesting to see how versatile those chips are, with parallel port programming and such... I might use one in the future too :-)

First, I wanted to confirm it made a huge progress to implement "interruptible track changes" (that is, for each track change request I receive, I immediately reply with only the first 27h frame of the track change sequence, and only after the user has finished playing with the thumbwheel for a 100ms timeout, I send the rest of the sequence (21h/21h/27h). Not a single HU_OFF anymore, and display follows the wheel movements much faster, without any annoying unmute/mute.

Well, second, not that I think anyone can do anything about it (except me), but I wanted to share my disappointment of yesterday :
I made a trip to Paris with the emulator and all worked well for about 1h30, then I began all of a sudden to have sound completely stopping (I had to pause/resume to re-activate SPDIF) once, twice, and then up to point where I could only hear two seconds of music before it stopped. On the next parking, I restarted the HU, restarted the PC, restarted the emulator... to no avail : every few seconds, the console says the HU has turned off (which is the sign of unacknowledged messages), and it is intermittent. I unplugged the adapter thinking maybe there was something overheating, but on the trip back, the problem occurred immediately though everything was cold.
The good news is that once the adapter is unplugged or emulator stopped, the actual CDC works perfectly, so it looks like the HU is not the culprit (and not damaged).
So my guess for now is a bad contact somewhere on my circuit and I'm going to have to track it down, which will be a real pain I guess (all cabling, circuits and HU are back in place). And to make things worse the problem is intermittent : If it's a bad contact, it might as well work again perfectly after I take the HU and PC out... :-(
The other possibility could be that a part has overheated and is now damaged.
Finally, it could also be that the mobo's serial port is damaged, but I don't think it's the case...
Where do you think I have to start ?

I really thought I could now concentrate on software only, but it seems I'm a bit out of luck...

Originally Posted by pippolippi

If you send a number that's not valid bcd it will show a blank instead of the track number.

That could be an interesting way to indicate we're over 99 : currently, when the track position in winamp is over 99, I let the track# at 99, but it could be more logical to make it go blank...