MiSTer FPGA Forum

Moondandy wrote: ↑Fri Oct 08, 2021 4:45 pm Wow, you've really put a shift in on this, well done getting it so feature filled.

Could this system make use of an RTC or does it predate utilising one?

danielb wrote: ↑Fri Oct 08, 2021 3:42 pm Hi,

Well, the core is basically complete, and appears to be working rather well.

That said, there are a few expansions that were available for the original kit:

- Floppy disk system. This would be very difficult, at least for me. To do this, you would need precise documentation of the actual interface, and the original DOS ROMS. Some of this does exist for the Superboard, but even so, I suspect this is beyond my FPGA coding skills. There are some disk images on the web for the Superboard, but I don't know whether they would even theoretically work on the UK101.

- AY-3-8910 sound card - this would probably not be hard because it is the same sound system that is in a lot of other computers from the time. It should be very similar to the sound system of the Oric, for example. I don't know if any existing software supports this, and programming it from Basic would be a huge POKE-fest.

- Other monitor ROMs. There were several other monitors made for the UK101. Not sure whether there is much advantage in using them over what the core already has. There are also upgraded Basic versions available.

Another thing I can think of is variable clock speeds. This should be fairly simple, but may create side-effects that I would have to deal with.

Anyone have any preferences, or other ideas?

D.

EeDee wrote: ↑Fri Oct 08, 2021 7:12 pm

danielb wrote: ↑Fri Oct 08, 2021 3:42 pm Hi,

Well, the core is basically complete, and appears to be working rather well.

That said, there are a few expansions that were available for the original kit:

- Floppy disk system. This would be very difficult, at least for me. To do this, you would need precise documentation of the actual interface, and the original DOS ROMS. Some of this does exist for the Superboard, but even so, I suspect this is beyond my FPGA coding skills. There are some disk images on the web for the Superboard, but I don't know whether they would even theoretically work on the UK101.

- AY-3-8910 sound card - this would probably not be hard because it is the same sound system that is in a lot of other computers from the time. It should be very similar to the sound system of the Oric, for example. I don't know if any existing software supports this, and programming it from Basic would be a huge POKE-fest.

- Other monitor ROMs. There were several other monitors made for the UK101. Not sure whether there is much advantage in using them over what the core already has. There are also upgraded Basic versions available.

Another thing I can think of is variable clock speeds. This should be fairly simple, but may create side-effects that I would have to deal with.

Anyone have any preferences, or other ideas?

D.

Hi Daniel

Would adding a Superboard mode with NTSC ect help/be feasible?
I also came across this and wondered if it would be of any use regarding disk drive implementation https://hackaday.io/project/173783-osi- ... em-osisdos
Sound and RTC sound good and swapping ROMs in and out also sounds like a handy option.
You mentioned variable clock speeds. That and an AY-3-8910 sounds good.
I suppose, to me, a core with lots of options is more interesting.

danielb wrote: ↑Thu Oct 07, 2021 7:38 pm Hi all, I pushed a new version with the 64x32 screen mode to the main repository.
To go with this, I am attaching a Scramble game that I downloaded from here: http://osi.vintagecomputers.square7.ch/seite3.html, that runs on a 64x32 screen under Cegmon. It's machine code so load it via the monitor. It's apparently called Super Scramble, by Adventure 10, 1982.

D.

danielb wrote: ↑Sun Oct 10, 2021 5:14 pm New test version with switchable clock speed. Gives speeds between 1 and 10 Mhz. Higher speeds are hilarious. Playing Scramble at 2 or 4Mhz is actually a big improvement.

I want to clean up the code for this a bit before making it official, so it might be a while.

D.

danielb wrote: ↑Fri Oct 08, 2021 3:42 pm
- Floppy disk system. This would be very difficult, at least for me. To do this, you would need precise documentation of the actual interface, and the original DOS ROMS. Some of this does exist for the Superboard, but even so, I suspect this is beyond my FPGA coding skills. There are some disk images on the web for the Superboard, but I don't know whether they would even theoretically work on the UK101.

EeDee wrote: ↑Wed Oct 13, 2021 6:50 pm

danielb wrote: ↑Fri Oct 08, 2021 3:42 pm
- Floppy disk system. This would be very difficult, at least for me. To do this, you would need precise documentation of the actual interface, and the original DOS ROMS. Some of this does exist for the Superboard, but even so, I suspect this is beyond my FPGA coding skills. There are some disk images on the web for the Superboard, but I don't know whether they would even theoretically work on the UK101.

Not just for you I think: https://stardot.org.uk/forums/viewtopic.php?t=13550 (3rd post down and Link in the last one)

EeDee wrote: ↑Wed Oct 13, 2021 9:05 pm There are
How about a 48x32 mode (it was a common double the Video RAM mod) which would be a useful addition I think. And maybe a way of saving without requiring serial?
You could leave the rest for future development if you ever felt like coming back to it.

danielb wrote: ↑Wed Oct 13, 2021 9:14 pm One thing I have found out is that the OSI machines apparently had a different character set, and that some games written for them don't look right on the UK101 for that reason. Adding a selectable character set should be trivial.

danielb wrote: ↑Wed Oct 13, 2021 9:14 pm
48x32 shouldn't be that hard, I think.

As for saving, not sure what's involved. Might be useful if people actually intend to write programs using the core

RedskullDC wrote: ↑Thu Oct 14, 2021 3:41 am Hi DanielB, et al.

danielb wrote: ↑Wed Oct 13, 2021 9:14 pm One thing I have found out is that the OSI machines apparently had a different character set, and that some games written for them don't look right on the UK101 for that reason. Adding a selectable character set should be trivial.

VHDL code for the OSI charater set is in the archive I posted earlier (if you want to use it):
http://www.crisis.com.au/images/OSI_Searle_Q17.zip

OSI machines also clock out the video bits in the reverse order to the UK101.

Perhaps UK101 designers trying to make it a bit more different for copyright reasons?

Cheers,
Red

EeDee wrote: ↑Thu Oct 14, 2021 5:57 am

danielb wrote: ↑Wed Oct 13, 2021 9:14 pm
48x32 shouldn't be that hard, I think.

As for saving, not sure what's involved. Might be useful if people actually intend to write programs using the core

The idea of writing and saving on old computers, I owned in the past, was one of the reasons I was attracted to Mister as a platform but that aspect has been the biggest letdown for me as it's, mostly, not implemented for whatever reason. It seems to be of little interest to most. Playing games is the main attraction, which is fine, but not the main interest for me. I was entertaining the hope that this may be the one for me
Having said all that it's been interesting watching your core develop. You're doing a good job

danielb wrote: ↑Thu Oct 14, 2021 6:06 am I really need to find out exactly what the differences were between the UK101 and the OSI machines, and also the differences between the different OSI models,

danielb wrote: ↑Thu Oct 14, 2021 6:11 am
I will definitely be looking at saving basic programs to text files using the core.

D.