QL-VGA, the second

The last few weeks I continued working on the QL-VGA adapter, for once to have one myself and also because I was pretty strongly petitioned by some people. I’m not an electronics guy by trade, so this is some tough order for me. The first PCB I ordered looked gorgeous, but it was already obsolete… Read More »

ZX81 composite output

Recently I decided to dust off my old ZX81, the very machine that I learned programming on some 30+ years ago. It’s getting kind of difficult to find a TV that works with it, especially as I have the 1st ULA version that didn’t do the sync signals correctly. So I decided to “invest” (it’s… Read More »

QL-VGA (part 1?)

The QL and its non-standard video interface has always been a problem, even more so since the introduction of LCD monitors. Since I got my QL out of storage a few years ago I’ve been looking for a solution. I bought all kinds of Chinese video converters, the GBS8220 for example produced a very unstable… Read More »

Quartus 18.1 MegaWizard problem

When importing a project into Quartus 18.1 it helpfully suggests that it can rebuild the PLL IP blocks. Problem is, afterwards the MegaWizard doesn’t want to recognise the blocks anymore. It doesn’t even show an error, it just doesn’t do anything. As somebody who has never even used a MegaWizard before that was somewhat unfortunate.… Read More »

QL-SD demo update

Prompted by a customer request I have extended my QL-SD demo file with a few free QL games, 20 in total, including some that were never available for free before but for which I have the rights to release (basically the Jochen Merz catalog, thanks Jochen!). I went to great length to try to make… Read More »

Microdrive mystery

Martyn Hill, while testing his brand new Tetroid SuperGoldCard clone, has discovered a strange bug where his QL crashed when he was loading a _scr file into the QL’s screen memory. It works fine without the SuperGoldCard. A lot of theories were put forward, like: It’s a problem with the SuperGoldCard: turns out it works… Read More »

(Super)GoldCard boot sequence

The last few days I’ve spent way too much time analyzing the (Super)GoldCard boot ROM. The sources supplied along with SMSQ/E are only sparsely commented disassembly that was basically impossible to read. It irked me to no end that I didn’t understand the code and finally I did something about it. The process had a… Read More »

QL-SD teaser

The QL-SD driver seems to be finished (note that it currently doesn’t work with the MiST FPGA board, but there are no more known problems with either the original QL hardware or the MiSTer FPGA machine). Now the boring part has begun, which means hours of reading tax related stuff (selling stuff internationally is hard!),… Read More »