RE: Video Streams for 8-bit Commodores

From: Marko Mäkelä (
Date: 2001-08-21 09:02:56

On Tue, 21 Aug 2001 wrote:

> A 16MB REU substitute sounds good! 

I went on designing the circuit board last night.  It seems that including
something like the Action Replay would exhaust the 64 programmable I/O
lines of the Lattice 2064.  Either the Flash ROM should be made smaller,
or some external components would have to be used.  The REU doesn't
require the ROMH, GAME, IRQ and NMI signals (well, in principle it
requires IRQ, but does any software use the "interrupt after transfer
completed" feature?), or a "freeze" switch.  So, it'll probably be 16 MB
of SDRAM and 8 MB of Flash ROM.  I hope that there is a possibility of
getting samples or small quantities of these chips.

> The 1MHz processor might still struggle though to stream video and audio
> data simultaneously without the assistance of other hardware. I suppose the
> processor would focus on playing a digi and interleave short DMA bursts to
> transfer the video frames.

You could store the digitized audio to the REU as well.  If the -GAME line
was wired to the cartridge, you could avoid copying the video data, since
the video chip could access it on the cartridge in the UltiMax mode
(addresses $2000-$2fff or $3000-$3fff, I forget which).


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