gertk's latest activity

All the traces with the dark spots next to the battery are suspect. Rub or scrape off the silkscreen carefully (a glasfiber pen is...

The Exidy Sorcerer came with a Z80 assembler but for more serious programming I recommend crossassembling on a PC (I use Linux and there...

Example

I have updated the GAL files and the schematic so the DISEN signal is delayed. Not perfect yet and the cursor still has to be delayed too.

Seems they are quite scarce.

Ah yes, but now it is public :-)

For the GAL equations and initial schematic: https://github.com/gertk64/BBC_Video_ULA

Making progress, all modes seem to work but still having some issues. First the whole screen seems shifted a bit to the right and on the...

Yes, for now I leave in the 74LS161 as base clock generator. I added a 74LS157 for selecting RGB between Teletext mode and the other...

I was not sure about the CRTCLK part so I tried connecting it directly to the CLK1 (1 MHz) output (just as I did with the 74LS161) also...

I have used 25 ns ST's which always worked fine for other projects. The newer 15ns Lattice 16V8 I have give an overcurrent error on the...

Small update: I managed to get the BBC running with a 74LS161 for the clock divider instead of the GAL logic. Probably the GAL did not...

Hi, My video ULA recently died in the BBC B here, no clock signals whatsoever, tried it in another BBC and no startup either. I tried...