Re: TED based motherboard

From: Grósz Attila (
Date: 2007-04-04 12:39:10


William Levak <> írta:

> ted-lo   looks like $8000-BFFF
> ted-hilo looks like $C000-DFFF
> ted-hihi looks like $E000-FFFF
> $390-770 in ted-lo looks like it should be the command
list, but it is 
> obviously garbled.

It looks very odd indeed. I made a quick disassembly and it
is not total
garbage though. It has code fragments that look like actual
TED register
manipulations which is odd considering that this area is
supposed to be
the BASIC ROM. Look at this:
. 81d0 ad 1c ff 	 LDA $ff1c
. 81d3 29 0f 		 AND #$0f
. 81d5 09 08 		 ORA #$08
. 81d7 8d 1c ff 	 STA $ff1c
. 81da ad 1d ff 	 LDA $ff1d
. 81dd c9 9b 		 CMP #$9b

This is the vertical line count register (which is writable
for the TED machines).
Weird thing is that this feature wasn't even used in
production ROMs only in
a few games and demos much later.

If I just take the 16kb HI ROM, and booted: it sets NTSC
mode and sort of freezes.
(tried it in Yape)

I must admit it looks very different from the final kernal
ROM, with I/O data
addresses $FE00-$FE1F that are unmapped in the production

I'll look further. Very interesting!


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