Sony Xplod Stereo Interface

[sumdog]

Hey there,

First I'd like to say that RockBox is amazing. I hesitated on getting an iPod simply because half my music collection is in OGG format and after learning about RockBox and purchasing an iPod, I am amazed at how well it plays all my ogg files, even very high bitrate oggs. This is an amazing alternative OS and I love it.

Ok, now onto my question. I purchased a Sony in-dash head unit with the optional iPod controller unit. I wasn't sure if Rockbox would work with such units so I tried out my iPod in various iPod docking speakers and devices at Bestbuy and it seems to work fine on all of them (forward back buttons didn't work, but I don't really care about those. I'd have the iPod mounted in a location where I could tap them in my car).

So I got the iPod connector installed in my car but when I hook up the iPod running rockbox, I can barely heard the audio. It's only audible when the volume on the Sony is turned up to the max. I can hear it and the iPod is charging off the cable. I attempted changing the pre-amp settings within Rockbox but that didn't seem to help and the output from the interface cable doesn't seem to be affected by the player/headphone jack volume.

I used a small connector and the AUX port on the stereo and it works fine, and although I'm more than happy to use this configuration, is there anyway to increase the preamp on the interface cable output? Has anyone else had issues with interfacing their iPod with a Sony controller?

Thanks
Sumit Khanna

[sumdog]

Answering my own question: I rebooted into iPod OS and added a song. It worked with the Sony adapter fine. In fact when I hooked it up, the screen changed to an Xplod logo with the words "Press OK to disconnect" under it.

I guess unlike the speaker adapters that just pull from the iPod's sound pins and send very primitive singles for Next and Previous. The Sony unit actually establishes a two-way connection with the unit which hasn't been implemented in RockBox (is this what's referred to in the FAQ as the "serial" interface?)

In any case, it doesn't matter. I kinda though this would happen which is why I bought a head unit with AUX in. I guess the Sony adapter will just turn into a very expensive charger.

Has anyone done any work on getting RockBox to interface with devices designed to work with a stock iPod? Is there any code in CVS? I'd be kinda interested in taking a look as it's been a while since I've worked on an open source project.

[safetydan]

I don't believe any work has been done for the serial interface of the iPod. There's a couple of issues that need to be sorted before anything can really be done. First would be finding some documentation (or at least reverse engineering) how to talk to the serial interface chip. The second problem is that the Apple Accessory protocol is undocumented.

[GodEater]

The second problem is that the Apple Accessory protocol is undocumented.

*Officially* undocumented. The iPL guys have gone some way to reverse engineering it - but of course without being able to drive the serial interface, it's absolutely no use...

[sumdog]

I found the iPodLinux page describing the protocol:

http://ipodlinux.org/Apple_Accessory_Protocol

It's a rough reversed engineered list and it's for the 3rd gen so it's probably been added to or completely changed for later versions.