OCULA - a ULA replacement concept

[Sodiumlightbaby]

So after some tweaking I managed to get _some_ LOCI functionality up and running. TAP and ROM is basically working good enough that I can run some test applications. DSK fails, so perhaps an issue with MAP timing.

Got the HIRES working pretty fast after text mode was working, but had some issues with Defence Force and Impossible Mission in the forced text region (bottom 3 text lines). Defence force the ground looked like it was repeating but condenced so obviously something wrong with the character lookup. Then I checked the reference and it struck me, it was using double height text which I hadn't implemented yet. Once that was in order it looked perfect.

ocula_bad_good_df.jpg

Impossible Mission was a bit more tricky. The game is supposed to show only black in the bottom three lines, but for some reasons OCULA was sometimes showing striped blocks. Firing up Oricutron with Impossible Mission and inspecting the memory at that text region showed the game uses it for extra storage but hides it by setting ink to black at the beginning of the line. It also took care to not use the upper bit in the data stored there so the inversion attribute wouldn't be triggered. But for some reason OCULA still triggered inversion. Turned out I had forgotten to mask out the upper bits when fetching the character data, which in this case was other data. So some times the data had the upper bit set and triggered video inversion for that line.

ocula_bad_good_im10.jpg

I've tested the diag ROM, and RAM and graphics is passing (including double height and flashing). For some reason it fails to detect the VIA, which is very odd, but just as sign we're far from done

(Sorry for the different hues in the pictures, I've got a bad connection in my cable again)

[Dbug]

You could try the Oric Atmos demonstration tape, it uses quite a few attributes, double size and stuff, lores 1, etc...

And 4K Kong uses double height characters in the bottom lines as well to show the score and the number of lives remaining

[Sodiumlightbaby]

Seems to be working fine as far as I can see, 4k Kong, Oric-1 demo and Atmos demo (for Kenneth)

ocula_4kk.jpg

ocula_oric1_demo.jpg

ocula_atmos_demo.jpg

[Chema]

This is incredible advance in so limited time. My most sincere congratulations!

[Sodiumlightbaby]

Fear not, work has not stopped! A lot of effort has gone into the base platform shared between OCULA and PIVIC. The OCULA specific stability issues with DSK emulation was solved with (drum roll) RV1 adjustment! So there is a little timing difference between the original ULA and the OCULA, but I'll put it on the "would be nice to understand later" TODO list.

But now I'm seeing double!

ocula_dual_display_b7game.jpg

ocula_dual_display_pte.jpg

The DVI output mode is currently 640x480 with 2x scaling for width and height. Red area is the area outside the Oric display and will be made black later - this is an alignment debug view. The DVI output is not synchronous to the Oric framerate so it will tear. We'll see how close we can get when we get the other DVI modes set up and tuned. It's a trade-off between sticking to (close to) conformant timing on the DVI output vs being locked to the Oric frame rate.

ocula_mounted_stack_dvi.jpg

Also the display connector is stiffer than I imagined and interferes with the other connectors on the board. I need to use a tower of sockets to have it clear the cassette port in the rear. It's plausible that an angled connector could work, but after working with the FFC setup on PIVIC I think the solution I prefer is to move to FFC on OCULA as well and have an adapter board which can be used as a modulator replacement. The hole won't support a full size display connector but a "mini" or "micro" will work. The reason for going with different connectors on OCULA and PIVIC was partly a risk mitigation move to begin with so this is fine

[iss]

... was solved with (drum roll) RV1 adjustment!

Great progress!

[ibisum]

This is astonishing progress! Excellent work, sodiumlightbaby! You have become an Oric Hardware God, in my opinion. Time for a promotion!

[Sodiumlightbaby]

Thanks for the support, it's much apprechiated. But it's not just me, remember dreamseal is also on the team The core platform and firmware with all the general services is shared between OCULA and PIVIC and we're currently spitting out firmware for both twins on the same build.

[ibisum]

Both of you kick ass, but you deserve a huge promotion just for LOCI alone. But yeah, awesome work fellas. You have managed to invigorate the Oric world with such wonderful peripherals, it cannot be understated.

There was a time when we were all kind of desperate to work out how to get storage sorted for Oric. And now it is 100% sorted. And busted ULA's, almost irreplaceable? Also 100% sorted. Sheesh.

As someone who grew up with Oric-1 and cassettes, the newfound wonders you've given us are just so cool.

[Gliou]

Fantastic