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Subject: Need help with CD changer emulator project

Need help with CD changer emulator project

From: Fernando Pedro Birra <>
Date: Fri, 30 Jul 2004 14:02:54 -0000

Hi all,
I've been actively working on a CD changer emulator for in car use. In
this case it is for BMW vehicles equipped with IBUS communication bus.
This includes the current 3 series, older 5 and 7 series, as well as the
Z3. The emulation is almost finished and I've been using it in my car
for several months. I started from the Alpine M-BUS plugin written by
Jörg and built around it as the buses share some electrical
characteristics (1-wire only serial communication, pulled up to 12 V,
Everything works well as long as I use the player version. My recorder
builds are not working at all and, since I don't have a recorder I can't
debug it properly. It seems that it starts up well, sends a couple of
messages to the bus but it hangs at some point later. At least this is
what people trying to use the recorder version tells me.
At startup the code reads some settings and displays a greeting message
on the screen. A guy that tried the firmware told me that he didn't see
any greeting message at all, which leads me to believe that the code is
crashing quite soon...
So, this is my help request: Can someone try to debug my code at least
to a point where it displays some stuff on the recorder's screen?
The source code can be found at
To compile it for the recorder I had to do some changes because the
final firmware was greater than 200k. I just renamed debug_menu.c to and added a fake_dbg.c file with empty replacement
The other change that is needed is to call the emulator at startup. I
did this by changing the app_main() function in the main.c file inside
the apps dir:
void emu_main(void);
void app_main(void)
The files all go into the apps directory.
To run the emulator we need to have a BMW directory created at the root
level and place there the ibus.ini file. There should also be some
playlists there but it is not necessary unless you really want to use it
in your BMW ;)
Thanks in advance.
Fernando Birra
Received on 2004-07-30

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