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Subject: RE: cvs: firmware/drivers button.c,1.14,1.15
From: Nielsen Linus (ext) (Linus.Nielsen_at_elema.siemens.se)
Date: 2002-07-01


> To achieve this there are somes questions :
> - are the line-in , ear connectors (and also the
> others) only useable by the Audio chip ?

Yes, that is the case.

> - if yes, could we use it to pass throgh the data
> received "as they are" we could use a kind of encapsulation ?
> define a protocol to transport data through this
> audio chip and then pass it to(or from for the AJ in
> "master" mode) the uProcessor/ Ata drivers to write(or read
> for the "master") it .
>
> I'd know it could become complicated, but I'm conviced it
> could be usefull !!
> So I wait for any comments about the possibility to implement
> it ? and about the potential users, appliations ?

This is certainly possible to do. But we need to program the DSP in the MP3
chip to do it. Today it can only encode/decode MP3 audio. That is a lossy
process, so transferring files that way is very hard. That would require the
CPU to encode the file as MP3, which would take all day...

If we can write our own DSP code for the MP3 chip we can implement a simple
audio modulation/demodulation scheme, similar to a modem, to transfer binary
data via the audio lines.

That is however not an easy task, and we don't have any info on how to
program the DSP. But never say never...

/Linus



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