That's a great idea - I had thought that it would be useful to have the Jed files available (though I did have another machine that I use just for programming PLD/ROMS so I ended up installing WinCupl anyway).

Ah, so that's how they overcome the memory limitation. Just looked up the color command - that is a bit weird but I can see why it is done that way. The colour tables are very closely mapped with the character definitions. I ran into this oddity when I was running some tests via the 6809 and wanted ...

Excellent - glad that worked. I find it is a valuable debugging tool particularly when working with numerous unknowns.

LOL, yes, I got as far as testing PRINT "HELLO" before giving up trying to workout where all the various keys got mapped to ... I admire your endurance!

Hi David, It's great that the swap worked. I'm curious what failed with MAME? Were you able to select the ROM to load? Are you running the crvision emulation? In case it helps you can also specify the path on the command line e.g. ./mame -window -debug -resolution 640x480 crvision -cart /full/path/t...

I think you can put the ROMs anywhere, when you start it up you need to press Fn-delete (at least on my Mac that's the key combination to enable the menu). Then hit the "Tab" key to bring up the menu, select File manager, then Cartridge, navigate to where you placed your rom and select it....

I have no idea of the creativision details myself but the MAME implementation may give some clues. On the face of it, it does look like there is only 1 KB of memory: map(0x0000, 0x03ff).mirror(0x0c00).ram(); And there are two banks of ROM that can be up to 8 KB each: map(0x4000, 0x7fff).rom().share(...

Great work Greg - congratulations on getting it all running. It's quite nice seeing a complete stand-alone system like that.

were sometimes occuring at the left of the screen instead of where they were supposed to be (as though the x position was lost) Ah, that's exactly the kind of behaviour I was noticing as well i.e. not so much a corruption in what is displayed but rather more like not quite receiving the right instr...

Either way, it would be interesting to see if a 74AHCT244 makes a difference. If you get the opportunity to try one. OK, so I got my hands on a 74AHCT244 and a 74AHCT04 ... neither really made a difference. Now I'm wondering if it was because I didn't make use of the blanking period for the writing...

Did you mean that W4 was garbled regardless of 12MHz or 16MHz, but at W6 it was fine at 12MHz? My apologies, yes that is what I meant to write (I was jumping around between working on the 6309/6809 issue and this other issue and was getting a bit careless with my typing). I don't have any AHCT devi...