Hacking the Audi Concert Pt 2 – Front panel, Keypad

SO into deep hack. I want to be able to talk to the front display and buttons. Although I plan to replace the deck this doesnt give me all the buttons I might want. A quick poke shows that I get 3 buttons to work with if I pick the deck commands up as is. I’d like more and I’d also like the front panel to say something other than ‘TAPE’

The Concert and Chorus are more or less the same thing so the manual here covers both. A quick look shows us we want X1001 (The front panel connector) and in particular pins 2, 3 and 4. These compose the SPI interface to the panel. With my analyser set for Active low clock, validon  leading edge and enable (status) active high I’m able to see whats going on.

Now I’ve only been looking at these three lines and something that is imediately of concern is that the schematis shows these as unidirectional TO the display. I beleive this to be an error.  Status is shown as originating from the display, again, I’m not sure on this one.

Watching the exchange its imediately clear that there is a simple command set in use here. The first byte seems to specify if the data of coming from the keypad or to the display. The keypad is pretty simple.

The first byte is always 0x25 followed by a key ID. A key up is sent when a key is released (0x21).

The keycodes apear to be:

0x01 – 1
0x02 – 2
0x03 – 3
0x04 – 4
0x05 – 5
0x06 – 6
0x07 – Seek >
0x08 – TP
0x09 – RDS
0x0A – CPS
0x0B – MODE
0x0C – <<
0x0D – FAD
0x0E – BAL
0x10 – BASS
0x11 – AM
0x12 – Dolby
0x13 – >>
0x14 – TREB
0x15 – AS
0x16 – SCAN
0x17 – FM
0x18 – Seek <
0x19 – REV
0x1A – Knob +
0x1B – Knob –
0x1E – Code in (TP+RDS)

There may be others but this seems to cover most. Interestingly the controller is pretty dumb, switching to tap or CD doesnt diable the unused button, the micro on the board just ignores it. This means intercepting these unuded keys should be trivial enough giving full use of ALL buttons.

On boot the keypad does send 0x25, 0x00 which seems to be a message stating that no keys are down at boot. I’ll verify this.

So in summary for the keypad, this all looks very simple to get to. I could now simply drop into tape mode as per the original firmware and be done but as I plan to have both bluetooth and MP3 built I’d like more functionality and that means the display.

So, on to the display…

3 thoughts on “Hacking the Audi Concert Pt 2 – Front panel, Keypad”

  1. Hello,

    i am writing to you because unfortunately its not clear your article for me.I am looking for solution to remote control for my Delta CC radio.As i read correctly you would also like to implement such as remote controlling for your Concert I radio.
    As i good read you captured signals at Data,Clock,Enabled connectors.
    Is this correct that if i push one button it will send out to the Data line?So send back the same to the Remote control input it will do the same as pushing the button?
    I am confused a bit because i have read this article before:
    He captured the radio remote control relays signals and he wrotes different values as yours:
    for example:
    Kovos: 0x9B SCAN
    Yours 0x16 – SCAN

    I hope we can discuss about these things.looking forward to hear you

    1. Its been a while and sorry for the delay. A lot depens on interpretation of the signals. I seem to recall there is a button down and a release signal as well, make sure you are getting both.
      As it goes the project didnt go much further. After all the digging its now been sat on the end of my bench for a year. Both cars I was doing this for have now gone so the drive has gone too.

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