BimmerBox: BMW CD Changer Emulator for Archos MP3 players

Here you can download BimmerBox: Archos firmware that emulates the behavior of a BMW CD changer. You can also find the required circuit diagrams to build the required hardware interface. The firmware is based on the famous Rockbox opensource firmware. A big thank to all the Rockbox team that provided the foundations for this project.

If you are in a rush and know exactly what you are looking for, you can jump directly to the bottom of this page.

Latest Flashable Version for Player/Studio with support for NAV display is 1.0b12 (January 30, 2007)

Current Stable Version is 0.96 (October 10, 2004)

Current Beta Version is 0.99z4 (September 26, 2005)

Donations

If you like BimmerBox and find it useful for use in your car you are welcome to make a donation to help me keep its development. Since I started this project I’ve “burned” 3 archos players and spent countless hours developing the software.

Compatible Archos MP3 players

Basically, we need an Archos MP3 player supported by the Rockbox firmware. But that is not all, we also need a player that supports the original remote control from Archos. You can view a picture of the remote control here. To my best knowledge the compatible players are:

• Jukebox 5000
• Jukebox 6000
• Jukebox Recorder (6Gb)
• Jukebox Recorder 10
• Jukebox Recorder 20
• Studio 10
• Studio 20

I'm not sure if it works on the Recorder V2 players but it won't work with the FM Recorder version.

Hardware Interface

Inside most BMW cars there is a communication bus (IBUS) that is used for several (non-critical) functions. One of them is the comunication between the Radio headunit and the CD Changer. By connecting the Archos to this bus we can make it behave just like an ordinary BMW CD Changer (or perhaps even better). Fortunately, deep inside the earphone jack there is an extra pin that is used to accept commands from the Archos remote control. This pin can be programmed not only to receive data but also to send and this is what makes the Archos Jukebox so nice. However to connect the archos to the IBUS we need an hardware interface...

The interface was designed by my friend Richard Moulds. I consider him an electronics wizard or a genius if you prefer. Where all others have failed he has succeeded. The interface poses some interesting challanges since it is bidirectional and it has some special current requirements that are imposed by the eletrical characteristics of the IBUS (The BUS inside most BMW cars). It can be built from very simple discrete components and you can download a pdf here.

As an alternative you can also build John’s simple interface. I had a few problems with this interface in my car when I set the volume too loud.

We are also working on a newer interface that will allow the archos to be charged inside the car and left there if we want to. This is under development but we expect it to be finished very soon.

Software Features

Think of a playlist as the archos counterpart to a CD in a CD changer. This is the idea behind my implementation. Each CD Changer disc is achieved by using a playlist. The original BMW CD Changer has a limited 6 disc capacity. Six is also the number of buttons on the radio that provide direct disc access. I decided to offer virtual magazines which will allow the user to access several different sets of 6 discs (1 magazine), one at a time. Below is a list of features that I think are worth mentioning.

• Virtual magazines. Magazines can be rotated to acess the next 6 discs.
• MP3 ID3 Tags can be displayed on the radio headunit, Multi Informative Display, NAV Screen or on the OBC Text bar, depending on the model of the car and the equipment installed.
• Several display modes (Track name, Album, Artist, Elapsed/Total track time, Track number inside playlist)
• Steering wheel buttons dedicated to the telephone can be used to control some features of the Jukebox like magazine rotation or display mode if you don't have a phone installed.

Installation

The easiest way to install the firmware is by downloading the current rockbox distribution for your Jukebox and follow the instructions on the rockbox site. The installation will leave the rockbox firmware file in the root folder as well a directory called .rockbox that is vital in order for the firmware to work. After this step download my archos.mod or ajbrec.ajz  modified files and replace the one in the root folder of your jukebox that was installed in the previous step. You can get the current BimmerBox version at the bottom of this page.

Now you need to setup the playlists that will appear as the discs of the CD changer. The playlists need to be created inside a folder called BMW at the root of your disc. The playlist names need to follow this sequence: DISC1.M3U, DISC2.M3U, DISC3.M3U, etc. DISC1.M3U..DISC6.M3U will make up the first virtual magazine. DISC7.M3U..DISC12.M3U will make up the second virtual magazine and so on.

You can leave holes in a magazine, but if you leave out all the playlists from a specific magazine that will be understood as if there are no further magazines and a subsequent magazine rotation will return to the first one.

Inside the BMW directory you will also need to place a file called ibus.ini that is used to configure some options. All options are specified by writing their name followed by the equal sign and the value we want:

OptionName = value

 These are the available options at this stage:

• DebugLevel
  0 for no debug, 1 for basic IBUS messages dump, 2 for more verbose debug info. The output debug file will be crated under the root folder with the name "out.txt";
• UsePhoneButtons
  Set this to true if you want to use the steering wheel phone buttons to control the archos;
• AlternateCDChanger
  Each device in the bus have a unique identifier. Most CD changers have the 18h byte id, but some have the 76h byte id. Set this property to true to set the Archos BUS address (id) to 76h, otherwise the more common 18h value will be used;
• AlternateStatus
  This slightly changes the replies sent to the radio as required by some headunits. Once again setting the value to true will force an alternative status message from the archos to the radio. The default is false;
• MuteHack
  Set this to true if the sound mutes at random times and it returns automatically at the start of the next track. Default is false;
• IntroTime
  Set this parameter to the number of seconds that each track is played while in SCAN mode. Default is 10 seconds;
• BatteryMinLevel (reserved for future use);
• IbusIdleTime (reserved for future use);
• MaxBatteryUsage (reserved for future use);
• ChargeTime (reserved for future use);
• ChargeSecondsPerUnit (reserved for future use);
• DischargeSecondsPerUnit (reserved for future use);
• AnnouncePeriod
  Set this to the number of seconds between announcing messages sent by the archos to let herself be known by the other devices in the bus. Default is 10 seconds;
• LeadingChar
  Some radios consume the leading spaces in the text messages sent to be displayed. For the scrolling effect if the radio eats out the leading spaces we need to replace them with some other char. The default is a dot character. To set this option use the character code of the character you want to use;
• DisplayWidth
  Set this to the width (in characters) of your informative screen. For instance E46 radios are 11 characters wide;
• DisplayRad
  Set this value to true if you want your radio to display informative text;
• DisplayIRIS
  Set this to true if you want your radio (E39 without MID) to display informative text;
• DisplayMID
  Set this value to true if you want your MID to display informative text;
• DisplayOBC
  Set this value to true if you want your OBC text bar to display informative text;
• DisplayNAV
  Set this value to true if you want your NAV screen to display informative text;
• DisplayPlaylistName (reserved for future use);
• ScrollSpeed
  Set this to the frequency of the scrolling effect. For instance, a value of 4 will mean 4 scrolls per second;
• ScrollDelay
  Set this to the number of scrolling steps to wait before starting to scroll.

Operating Instructions

Beside what is expeted there are some additional commands that can be used with the archos that are not available with a standard CD Changer.

• Rotate to the next magazine - Press the SCAN button twice in a short time or press the Talk button on the steering wheel
• Advance 10 songs - Press and keep pressed the right (>) button. This was originally meant to fast forward inside a track but this is not implemented at this time and I think it is more useful to have a way to skip 10 songs in a row since we might have hundreds of songs in a playlist;
• Go back 10 songs - Press and keep pressed the left (<) button.
• Rotate through the display modes - Press the R/T button on the steering wheel;

While skipping songs, the effect is delayed so that we can avoid the archos to issue lots of disc accesses. Requests are buffered and after 2 or 3 seconds it will jump to the final track.

Note: On some radios playlists are display as CD 1..CD 9, CD A..CD Z, CD a..CD z. For instace, playlist with the name DISC10.M3U will be displayed as CD A. My radio displays disc names like these and I use it to organize my music library by artists by grouping all artists with the same initial in the respective playlist.

Download

Stable versions:

Firmware for the Player/Studio (archos.mod) - BimmerBox Player/Studio Version 0.96
Firmware for the Recorder (ajbrec.ajz) - BimmerBox Recorder Version 0.96

Beta versions:

Firmware for the Player/Studio (archos.mod) - BimmerBox Player/Studio Version 0.99z4
Firmware for the Recorder (ajbrec.ajz) – BimmerBox Recorder Version 0.969dz4

Flashable versions:

For Player/Studio (rockbox.ucl) – BimmerBox Player/Studio Flashable Version 1.0b12
For Recorder (rockbox.ucl) – BimmerBox Recorder Flashable Version 0.99z4

Source Code – Not available at this time.