"what-if" QL extended graphics

[tofro]

I've finally found some time to tweak some demo code I've had for a couple of years and make a video out of it that shows the extended QL graphics idea: https://www.youtube.com/watch?v=7EizW3ZWNqc[/youtube]

Outch, that looks seriously impressive, especially the background scrolling + sprites part. Also, 16 colours apparently can look like a lot more once you can redefine the palette. I also like your approach to "develop HW" on the MISTer.

[Derek_Stewart]

Hi,

Great video, gave it the thumbs up, makes me want to get a Mister.

Maybe another idea, would be to use the Commodore SID chip for sound as well.

[dilwyn]

I enjoyed watching that. Thank you Daniele.

[Cristian]

So cool Daniele!

[Peter]

I've finally found some time to tweak some demo code I've had for a couple of years and make a video out of it that shows the extended QL graphics idea: https://www.youtube.com/watch?v=7EizW3ZWNqc[/youtube]

Great presentation video. I was wondering about the voice until it turned out to be AI generated.

Was the video memory implemenetd with SDRAM oder SRAM?

[M68008]

Was the video memory implemenetd with SDRAM oder SRAM?

My Mister has 32 MB SDRAM that is used for everything, including storing the QL RAM. I made no changes to that part of the QL FPGA code.

Had Sinclair really created a business+multimedia computer at the time, my guess is that they would have had to go with the Amiga approach, with a 16 bit bus and faster RAM, to allow two RAM accesses every 4 CPU cycles. That would allow fetching both the video and the sprites with minimal CPU slowdown.

An ULA replacement today would have to use a different approach since it is not possible to change the rest of the motherboard, and to partially fix the QL's slowness. It would have its own SDRAM and disable the QL RAM on the motherboard.

Trying to be compatible with the Gold Card (assuming it's possible) would also pose additional problems.

[lliont]

Great!
In my latest ula clone, I didn't replaced the ram but added a 64K shadow ram that the ula uses to read the video ram faster and it has a 30% video speed improvement because it steels less cycles from the cpu when it accesses the video ram but still with the 68008 that has the 8bit bus and a 1MB address space. To be able to replace the video ram one needs to use more signals than the ula socket provides so I just did this simple improvement.

[Peter]

To be able to replace the video ram one needs to use more signals than the ula socket provides so I just did this simple improvement.

I'm sure you are much more into this than me. If I remember correctly, the ULA can see all the signals of the QL DRAMs. Plus it can deactivate their RASL/CASL. So at first glance, I don't see why a circuit in the ULA socket could not replace the video RAM. Could you enlighten me?

[M68008]

The ULA gets 18 of the 20 address lines, so without extra connections it's limited to the original 128 KB of RAM.

[M68008]

Great!
In my latest ula clone, I didn't replaced the ram but added a 64K shadow ram that the ula uses to read the video ram faster and it has a 30% video speed improvement because it steels less cycles from the cpu when it accesses the video ram but still with the 68008 that has the 8bit bus and a 1MB address space. To be able to replace the video ram one needs to use more signals than the ula socket provides so I just did this simple improvement.

Any plans to use a bigger FPGA and increase the number of colors? That may allow merging our code if desired.