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Subject: Re: archos as a cd changer

Re: archos as a cd changer

From: Fernando Birra <>
Date: Thu, 1 Apr 2004 16:16:55 +0100

Hi guys,

please find the circuit diagram, source code and modified firmware based on
rockbox 2.1at this page:

Your comments are highly appreciated

Fernando Birra

"jobarjo" <> escreveu na mensagem
Fernando Birra wrote:

>I've started from the Alpine M-BUS plugin from Jörg and modified it to
>interact with the IBUS used in BMW cars. So now, I have an Archos "CD
>Changer" in my car...
Great! I think I should have bought an alpine... it would have been
simpler... But I like the CD text feature...

>The code from Jörg is very good (what else could we expect) and it already
>addresses most of the stuff you mention like hardware interrupts and
>queueing of request. I used a playlist approach to the emulation. For now I
>am simulating 6 discs (the radio only has 6 direct access buttons) using 6
>playlists stored at the root folder, called DISC1.M3U through DISC6.M3U. If
>you take a look at the code in the apps directory called playlist.c you
>find most of the code you need to start, shuffle, create, etc playlists. In
>my emulator I process the messages coming from the bus directly instead of
>using a gateway like you intend to do.
Why not keeping the behaviour of the standard archos buttons? you just
have to map your head unit buttons to archos buttons so you can keep all
functionallity and all evolutions of rockbox in your car...
for example you can map cd6 to the 'ON button', etc..
I intend to use the Head unit as a generic lcd display except that it
has 8 characters... (a little poor I know)
Is your code still a plugin that jorg did publish some times ago?

>If you want we could further discuss this topic using e-mail.
>Kind regards
>Fernando Birra
>PS. I will make the code available to all those interested. It is just that
>there are still some quite ugly piece of code in there and a bunch of bugs.
could you send it to me just for consultation? Please use 'sophana at' (the jobarjo78 mailbox is a thrash spammed mailbox)

>"jobarjo" <> escreveu na mensagem
>>Hi all
>>I finally succeeded in connecting a sony head unit to a pic16f84a with
>>the gnunilink software (
>>Now I would like it to comunicate with the archos.
>>I know I am not the only one wanting to do that. However I've had a look
>>in rockbox source, and it seems not easy to interact with the mpeg and
>>the status. I could not find any work for a tight integration between
>>the mp3 and an external device.
>>Could anyone show me a pointer to some work that has already been done?
>>The actual remote control stuff is polled! Is there a problem
>>implementing a non blocking interrupt handler? I need to implement it as
>>interrupt because the archos should respond in a limited time to
>>gnunilink requests.
>>What I propose is simple:
>>- actions are communicated from the interrupt handler to the firmware
>>through a queue to avoid critical sections.
>>- status are memory mapped. just need some small infos:
>> - disc name (folder name)
>> - track name
>> - time
>>no need for a mutex or something...
>>for the action queue i propose to use the button queue. navigation could
>>be done through standard archos behaviour just by mapping some specific
>>head unit actions into some archos buttons...
>>For the status, it would be the same, except that the head unit has 8
>>characters. the display is also polled by the gnunilink, so there will
>>be latency between actions and the display.
>>talkbox could help...
>>any comments welcome...


Received on 2004-04-01

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