Rockbox mail archiveSubject: RE: Reading from drive?
RE: Reading from drive?
From: Nielsen Linus (ext) <"Nielsen>
Date: Wed, 9 Jan 2002 10:14:48 +0100
> Well... Won't re-engineering the code offer any clues?
Of course it will. Feel free to do it... :-)
> I mean, the research notes indicates that the MPEG outport
> port pins are known. Given that, the code has to use them
> to make sounds.
Yes. Via a 1mbit/s serial interface.
> To make sounds, it has to use mp3 data. To get the mp3 data
> it has to read the disk...
> Given that the CPU has DMA, we might get some details by
> checking out how the DMA is controlled and check the code
> for DMA activity (assuming they use DMA for at least some
> parts of the above).
The IDE seems to use plain parallel I/O. The serial line is
probably using some kind of DMA, or the CPU would not keep
up with the speed of data. Or it may have a huge FIFO
which is filled by the CPU once in a while.
> Or am I out in the blue again?
As always... :-)
Received on 2002-01-09