The Sinclair QL Forum

I built the first new compact pcb ula basic replacement and it seems ok but I'll test it more.


This is how it measures with my qubide clone ram (https://hackaday.io/project/183490-qubi ... ade-for-ql )


I think the original with the qubide ram measures about 1.3 so at 1.586 it's just a little faster but not fast enough to cause problems with games so I'll leave the optimizations on.

Hi,

Great work Leon

/Chris

Nice job!

Thanks

This is the second compact ULA board that has 128K static ram that replaces the on board dynamic ram.


Because it replaces the ram it has a faster low memory access, this also means faster graphics. It measures 1.754

I had hoped for a compact board that keeps timings intact.
I want to be able to use the QL for test purposes, behaving exactly as with the original ULA.
Is there still a chance for that?

And merry christmas!

Merry Christmas!
Timings are intact in every memory access cycle (or it wouldn't work) and the clock is the same it just does less (unnecessary) cycles for the refreshing of dynamic memory.
You want it to work exactly as the original, this is not optimal but I'll try to make one specially for you based on Nasta's analysis. You can compare it with the original and give feedback.

Your case Peter is different and I understand but I believe and maybe I'm wrong that most users prefer the improved version of the ula than an exact clone.
It's not such a big speed difference to produce incompatibilities or unplayable games. Also in the second pcb there is the option to slow it down to about the same speed as the first pcb.

Speaking of improvements, both pcbs have also the ability to display the 16 colors by doing a small mod and a special scart cable.

I wonder if the 16 colors mode works with QL VGA adaptors

I knew I'll get into trouble the moment I mentioned the 16 color ability lol.
It is possible but needs some simple extra circuit. This is the basic ula replacement pcb.
I'll also try to make a profile for the rgb2hdmi adapter I have used for other retro machines.

lliont wrote: Sun Dec 24, 2023 12:59 am Your case Peter is different and I understand but I believe and maybe I'm wrong that most users prefer the improved version of the ula than an exact clone.

It depends on whether you want to set up a production and sales channel for a wider audience.
If you do, I think you would sell most as 1:1 replacement for the ULA as spare part. Just my personal guess.