Ogg+RTEMS on GameBoy Advance was Re: RTEMS device driver andinterrupt

Tue Apr 16 23:33:46 UTC 2002

Yep, have to fab a small pcb.
Thats pretty cheap actually.
Select all the components(I can do it in one day),
would expect the following:

Altera FPGA (or quick logic)
SD Socket.
serial prom for altera
parallel prom for boot of gb
mp3 decoder silicon
audio dac.
pcb
housing.
regulator and passives.

I'd have a small separate dac.

Maybe even a USB chip.
Think the GB would be nice to display
photos.

At 10:11 PM 4/16/2002, Lou Woods wrote:
> >>Pretty easy design if anyone is interested.
>
>Very interested.  How easy is it?  I am still very green.  You have to
>design and fab a pcb, right?  How hard would it be to interface with the
>bus system on the GBA?  How would you get around the hardware
>limitations of the GBA sound chip?
>
>
>Lou Woods
>Computer Engineer
>OAR Corporation
>(256) 722-9985
>Lou.Woods at OARCorp.com
>www.OARCorp.com
>
>
>-----Original Message-----
>From: Glenn West [mailto:gwest at nano-storage.com]
>Sent: Monday, April 15, 2002 8:49 PM
>To: rtems-users at oarcorp.com
>Subject: Re: Ogg+RTEMS on GameBoy Advance was Re: RTEMS device driver
>andinterrupt
>
>
>Thinking out of the box.
>
>Take a off-the-shelf MP3 decoder. (Quite a few nice ones
>with small die/package, combine it with a SD Slot (Very small), a 64K
>SRAM, and a small cheap fpga.
>
>You can either play thru the existing sound, or better put
>the codec local, have high quality. Also could have extra
>rom images in the SD card.
>
>Now you can stream the audio, and do nice
>images at the same time. (Might even be able
>to display some nice personal photos as well
>on the LcD.)
>
>Pretty easy design if anyone is interested.
>
>
>At 04:17 AM 4/13/2002, you wrote:
>
>
> >Craig Graham wrote:
> > >
> > > On Friday 12 April 2002 8:28 pm, you wrote:
> > > > Mike Panetta wrote:
> > > > > On Fri, 2002-04-12 at 11:32, Joel Sherrill wrote:
> > > > > > Mike Panetta wrote:
> > > > > > > Thinking GBA are we?  An ogg player for the GBA might be
> > > > > > > pretty
> > neat.
> > > > > > > Esp if it had some sort of visualization like winamp or
> > > > > > > whatnot.
> > > > > >
> > > > > > Busted.  So the big question now..
> > > > > >
> > > > > >   Is this a feasible project from a HW perspective?
> > > > > >
> > > > > > The GBA has 16 Mhz ARM, 32K+256K RAM, <= 256Mb flash, and as
> > > > > > best I can tell 8 bit stereo.  I know the sound won't please
> > > > > > an audiophile but is this doable given the HW limitations.
> > > > >
> > > > > I think we would need to have your previous question answered
> > > > > first, before we could make any educated guesses on that.  I
> > > > > myself do not
> > know
> > > > > much about the ogg format to guess :).  As for ram, I bet it
> > > > > would not be too hard to add some external ram where the flash
> > > > > would normally be. You would just need some sort of burst
> > > > > counter and address demux in an external CPLD I think.  The only
>
> > > > > thing I can think of that would
> > prevent
> > > > > it would be if the GBA disalowed writes to the ROM address
> > > > > space.  The burst counter and demux would be needed to interface
>
> > > > > flash anyways if I read the schematics right on the pages I
> > > > > looked at, so its not much added effort.  I do know about the
> > > > > RAM space that the GBA cartrage has, but it would only allow you
>
> > > > > to add an additional 64K of ram IIRC, which would not be
> > > > > significant (or would it?  I guess we would need to know buffer
> > > > > size requirements to figure that one out).
> > > >
> > > > I would prefer to be able to stick to off-the-shelf flash
> > > > cartridges for the GBA.  So even preprocessing files to a "game
> > > > boy audio" format on the host side would be OK by me if it made
> > > > processing easier on the GBA side and did not explode the size of
> > > > the files.
> > >
> > > I don't think you'll manage to play ogg files on GBA.
> > >
> > > Reasoning:
> > > It took almost the entire processing power of a Playstation1's R3000
> > core to
> > > play an MP3. MP3 & Ogg have roughly the same processing requirment.
> > > The PS1's R3000 was clocked at 30MHz, which is a fair bit faster
> > > than a
> > 16MHz
> > > ARM. QED, it won't work.
> >
> >:(  Well that sounds like we are going to have to look at
> >"preprocessing" files on the host side and only giving the GBA
> >something lighter.  I guess
> >the next step in the "feasibility study" is to see how the size of an
> >Ogg or MP3 file compares to the raw bit stream required to drive the
> >sound chip on the GBA.
> >
> > > Of course, if you prove me wrong I'm first in the first in the queue
>
> > > to
> > stick
> > > it on my GBA ;)
> >
> >:)
> >
> > > Craig.
> > > --
> > > Craig Graham <craig at data-uncertain.co.uk>
> > > Technology is like a war fought with symbols, words and gestures
> > > - all you have to lose is everything, so trust no-one...
> >
> >--
> >Joel Sherrill, Ph.D.             Director of Research & Development
> >joel at OARcorp.com                 On-Line Applications Research
> >Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> >Support Available                (256) 722-9985