VY/VZ Headunit Mod for Aux Input

[Nemesis04]

I'm not sure if this is relevant, or still readily sort after... But here goes.

I've been toying around with the idea to install an auxiliary input into a standard VY head unit from Blaupunkt. Many others have approached this and have had some success but all involved bypassing the audio processor to inject an audio signal directly into the amplifier at low level, or cutting the stereo source from the FM or CD player... I can't remember which. This, of course, worked but I thought that a different approach could be taken; to look at the audio processor (TDA7348).

Thankfully, (Unfortunately? Cheap Holden/Blaupunkt...) the TDA7348 audio input control has the capability to accept 3 stereo inputs and 1 mono (AM Radio) input... Only two of these stereo inputs are implemented and most board revisions that I've seen, perhaps three (the single stacker, 6cd stacker, and VZ stacker) have the support for an Auxiliary input. These components and associated pogo pins in the radio socket are not populated. The TDA7348 communicates on the I2C (TWI) bus, the only other I2C device that I could find on the same bus was the graphics equaliser (not implemented on the single stacker). This was good news, it meant that software could be used to select the additional unused input and could utilise the volume and audio corrections implemented by the TDA7348, including treble and bass controls without isolating any other input. After sniffing the I2C the TDA7348 has a standard packet where level corrections, volume, and finally input are selected. The order is arbitrary I believe, but a soft mute before and after packet transmission is recommended to prevent audible popping from speakers...

After some toying around with software and sniffing the SPI interface used to send commands to the board from the face plate, I've implemented a solution that selects the unused input when the pause button is selected and pipes it through the factory amplifier. The sound is crisp and of surprisingly good quality, I was pleased. It's sitting in a box behind a kick panel and uses an Atmega8 and a few discrete components and a large ribbon cable feeding into the head unit (will be fixed at a later date, its introducing noise to the I2C line and fooling the micro into thinking that a command is about to be sent)

I've stumbled across this forum after searching for modifications to the cluster and have read through many posts, so I thought that I'd contribute something that may have bothered people for a while.

This post may appear jumbled, its 5am in the morning lol, but I'll correct it later... just getting most of it out.

If there is any interest I'll compile source code (C for use with Atmel microcontrollers, no Ardunio... although I'm sure the code could be ported easily) and relevant schematics for all inputs and stereo control.

I know of one other bloke that has done this, but is selling the unit commercially...

I'll eventually look into sending text to the unit (there are different LCD versions, GLCD and alphanumeric, so the approach may not work for all) and populating the unused aux input track (filtering and etc) for a true factory solution. I've also been able to interpret commands sent from the head unit face plate, could be used to control iPod input in future? /shrugs.

As a result I'll keep this post updated with any new developments.

Cheers, Nem.

[jezzab]

Very cool mate. Well done!

[ZerOne]

Wow !!!!! Thats getting freaken hardcore !
Obviously a lot of work has been put in to this to get this far !
I bow down before you !

I used to mod old factory (analogue volume control) decks years years ago by as your were saying in your post, injecting audio just before the volume pot, and having the original audio source diverted to the 3.5mm Stereo audio socket (Which when plug was not inserted, simply diverted the audio back to the pot)...

Ahhhhh, simple times...

I have seen the above commercial mod you are talking about (For controlling iPod devices), and surprisingly the same guy is selling a very similar unit for the VE Series I head units (The Non Colour LCD units)...

I dont know if the Audio processor chip is the same, or if the VE models have a newer / different version, this is something that I should check out one day, but I know the VE models support an extra FM/Radio channel for Satellite Radio in the states (XMRadio I think its called, not too sure), as well as a myriad of other inputs (Aux Audio, and Sat-Nav Mono to name a few).

Looking at the VE iPod controller kit, there are a lot of connections that are made directly to the audio control board, so Its obvious that the method this guy is using is simply not pushing commands on the SW Can to display the iPod song and track details...

Very very interesting project !!!!!

[TazzI]

Ah iv always wanted to do an integrated solution for the stock blaupunkt. Iv simply done the 'inject audio in to the cd/fm sources' that overrides anything playing, its alright.. but nothing compared to an integrated!

More then interested in this project!

[Nemesis04]

Wow! seems like there still is a keen interest.

Alright, I'll see what I can scrounge up for you guys later tonight when I get home

Tazzi, Yeah I looked at that... considered it for a good while just to get something going... but CDs tied me over until this thing was finished.
lol, let me tell you though... it looked mighty appealing after playing with this thing for a few months....

...particularly when you get stumped on why the thing isn't working... when you're telling it to switch to the same input it was already in...... lol

...
I have seen the above commercial mod you are talking about (For controlling iPod devices), and surprisingly the same guy is selling a very similar unit for the VE Series I head units (The Non Colour LCD units)...

I dont know if the Audio processor chip is the same, or if the VE models have a newer / different version, this is something that I should check out one day, but I know the VE models support an extra FM/Radio channel for Satellite Radio in the states (XMRadio I think its called, not too sure), as well as a myriad of other inputs (Aux Audio, and Sat-Nav Mono to name a few).

Yeah, from what I've come across the approach is fairly similar, but you're right, you can't send commands to the screen over CAN (that I know of at least...), perhaps those ipods with video out could be integrated into the higher end VE H/Us and tv input automatically triggered when an iPod/Phone is plugged in... but... yeah...

Maybe via some diagnostic mode? Prompting the user for input that can be customised? I've seen something similar in the little Vauxhauls and newer Astra's. I'll see if I can find the link.

There's also a possibility you can send simple text to the dash display... but I don't think holden uses the same RS232 bus to connect the H/U directly to the dash cluster any more, shame really.
This can be done with the VY/VZ... just haven't gotten around to it yet lol. The packet format and data/commands is somewhat... illusive... at the moment lol

Those extra connections are for things like steering wheel control sensing, aerial input (I've stumbled across this as well, its included in the software but disabled currently until I can come up with a better solution), power for the micro and the myriad of IO lines that need to be hijacked.

Also, I think the TDA is a newer revision, the TAD7402 takes 3 stereo inputs. One for CD and another for FM... seems like it can be enabled in the same way.
A quick look at the datasheet looks like the TDA7348 and TDA7402 MIGHT be interchangeable... the TDA7402 has an integrad LPF and subwoofer output.... hmmmmmmmmmmmmmmmmmm.... the possibilities.

Cheers, Nem.

[Nemesis04]

I've found something that MAY be possible for sending text to the head unit...

I don't think this ever came to fruition and the XM radio may be key in this... unless the head unit can be fooled into thinking there is an XM radio attached (possible firmware swap?) and bit-bashing the xm radio comm line to the head unit to display relevant "RDS" data...

http://www.youtube.com/watch?v=wCxObzOl ... r_embedded

[TazzI]

Yeah the 'override cd/fm' mod does do the job, but has its limitations.. Such as additional relay and wiring required when a stock bluetooth kit is hooked into the Blaupunkt unit as well...Usually a call will mute all music and call comes through but the aux takes priority and gives no sh*ts!
Managed to get around this with a simple circuit that trips when a call comes through thus giving call priority. Im guessing using that free stereo input would act just like the cd and fm sources so factory bluetooth mute would work correctly without any modifications. (not really on topic but would make the bluetooth kit a whole lot less messy! haha)

As for the dash display, Do you mean in the left corner where usually the station number eg "FM 92.9" displays, Has to be enabled in the cluster first for anything to display though. Well I'd think sniffing the data through aldl would pick up the messages to the cluster when changing stations?

[Nemesis04]

Yeah the 'override cd/fm' mod does do the job, but has its limitations.. Such as additional relay and wiring required when a stock bluetooth kit is hooked into the Blaupunkt unit as well...Usually a call will mute all music and call comes through but the aux takes priority and gives no sh*ts!
Managed to get around this with a simple circuit that trips when a call comes through thus giving call priority. Im guessing using that free stereo input would act just like the cd and fm sources so factory bluetooth mute would work correctly without any modifications. (not really on topic but would make the bluetooth kit a whole lot less messy! haha)

Yeah, I had a similar problem when I tested a twin relay setup just to see what it was like. I got horrendous mechanical popping though, could have been my choice of relays but there was a diode in series over the coil and electrolytic caps on the inputs... I think it was just popping because the amp was being saturated from two sources at different amplitudes when it kept bouncing between inputs. /shrugs do you get any of that?

Bluetooth, that was a strange one. I think the audio path is separate from the TDA and its simply muted when an incoming call is detected. Ironically, the TDA is muted when I receive a call but because I'm not keeping track of the "phone enable" in software... after the call is finished the head unit goes back to what it "thinks" it was on before the call was placed so I have to enable aux in again. Not too much of a big deal, but can be irritating... lol... just have to set up an interrupt on a spare pin to watch when it goes high again and enable the aux in again.

What bluetooth unit do you have? I've got a fairly crappy nokia one that's rather old... people complain about drop outs in the middle of a conversation lol so I'm looking at swapping it for a more robust model.

As for the dash display, Do you mean in the left corner where usually the station number eg "FM 92.9" displays, Has to be enabled in the cluster first for anything to display though. Well I'd think sniffing the data through aldl would pick up the messages to the cluster when changing stations?

Yeah, I think you're right. Although as it stands that's something I might look into down the line... But for the moment I want to get the alphanumeric display on the head unit itself displaying "Aux In", or even track information.

... although it would be nice to have custom information sent to the cluster as a "message" to the driver... GPS directions with a friendly beep to tell you when to turn? Temperatures... tyre gauge pressures? etc I'll definitely have to look into that when I get some time.

I haven't hooked up a CRO to the aldl line just yet, but I've got a spare radio that I'm sure will still spit out data... I just hope it doesn't have to handshake with the cluster before it actually sends anything along the bus.

Have you played around with the old ALDL lines much? Any traps? lol

Cheers, Nem.

[Nemesis04]

Here's the software, It's not as elegant as it could be... I honestly wanted to get it working and once it was I dropped the project until now. When I get some free time I'm going to refine it and implement new features, such as aerial control, external phone input tracking (So it switches back to aux after a call ends) and some other fixes such as I2C validation.

Circuit diagram and pin outs to come.

[Nemesis04]

Here's the software, It's not as elegant as it could be... I honestly wanted to get it working and once it was I dropped the project until now. When I get some free time I'm going to refine it and implement new features, such as aerial control, external phone input tracking (So it switches back to aux after a call ends) and some other fixes such as I2C validation.

Circuit diagram and pin outs to come.

Well... I thought I attached the correct file... and now I can't edit the post. lol... here it is again... /face palm