Search found 61 matches

by rv6502
Thu Jul 01, 2021 9:41 pm
Forum: Games & Demos
Topic: Starduino Port WIP
Replies: 4
Views: 1812

Re: Starduino Port WIP

Man, do I feel silly :mrgreen: I was starting to go nuts trying to figure out why the nested interrupts were seemingly not working while the audio code was enabled. pic_4_1.jpg I forgot there was another audio mixer call in the vblank handler and I missed removing it during the refactoring a year ba...
by rv6502
Tue Jun 29, 2021 4:26 pm
Forum: Games & Demos
Topic: Starduino Port WIP
Replies: 4
Views: 1812

Re: Starduino Port WIP

But I broke the sound a while back... about a year ago. And I don't remember what I did exactly... (I do have the git history but it was a huge refactor so it doesn't narrow it down much.) Okay, that was a silly bunch of hours spent looking for the problem #if ARDUBOY_ENABLE_MUSIC || ARDUBOY_ENABLE...
by rv6502
Sat Jun 26, 2021 4:55 am
Forum: Games & Demos
Topic: Starduino Port WIP
Replies: 4
Views: 1812

Starduino Port WIP

Got it into the good-enough zone for the emulator to accept the picture. https://www.youtube.com/watch?v=6J3zQwqEydo But I broke the sound a while back... about a year ago. And I don't remember what I did exactly... (I do have the git history but it was a huge refactor so it doesn't narrow it down m...
by rv6502
Sat Jun 26, 2021 1:42 am
Forum: Uzebox Emulator
Topic: Emulation and sync behaviour of a CRT monitor
Replies: 6
Views: 5780

Re: Emulation and sync behaviour of a CRT monitor

Almost there.

I think I got the wrong number of scanlines. The emulator is alternating between showing a black screen and the video signal.
Untitled.jpg
Untitled.jpg (269.76 KiB) Viewed 2093 times
Or it's because I'm still missing the little blip at the end of the vblank:
pic_2_1.jpg
pic_2_1.jpg (131.49 KiB) Viewed 2093 times
by rv6502
Thu Jun 24, 2021 5:58 am
Forum: Uzebox Emulator
Topic: Pi Pico - Uzebox Emulator?
Replies: 3
Views: 1243

Re: Pi Pico - Uzebox Emulator?

Emulating the video generation properly would require much more than 10x the speed as the pixels position & size depends on exact timing, can't cheat and count opcodes in a "meh, close enough" fashion. 133Mhz ARM Cortex-M0 doesn't have the speed nor register count to do this. ARM CPUs are also terri...
by rv6502
Thu Jun 24, 2021 5:13 am
Forum: Uzebox Emulator
Topic: Emulation and sync behaviour of a CRT monitor
Replies: 6
Views: 5780

Re: Emulation and sync behaviour of a CRT monitor

As life things have calmed down a bit I'm slowly getting back into hobbies and got a new toy that saves the samples captured to CSV files so I can inspect in detail the mess I made of my signal generator :D Anyway, what sort of VSync you saw functioning then? An absolutely horrible one :lol: It's no...
by rv6502
Tue Dec 17, 2019 2:27 am
Forum: Off Topic
Topic: Intellivania: Castlevania for the Intellivision!
Replies: 11
Views: 10535

Re: Intellivania: Castlevania for the Intellivision!

Yes, that's also rather interesting, a quite unique CPU, in some regards it might do better than the 6510 due to being 16 bits. Otherwise it is not quite as fast by the clock counts in this Wiki, however it was clocked at almost twice the rate of the typical 6510 based machine (C64). The Wiki actua...
by rv6502
Fri Dec 13, 2019 3:42 am
Forum: Off Topic
Topic: Intellivania: Castlevania for the Intellivision!
Replies: 11
Views: 10535

Re: Intellivania: Castlevania for the Intellivision!

And it's a 16bits system!

But the ROMs were 12 bits wide to save cost which was possible thanks to the opcodes being only effectively 10bits long with 6 reserved bits.
by rv6502
Sun Nov 24, 2019 2:01 am
Forum: Uzebox Emulator
Topic: Emulation and sync behaviour of a CRT monitor
Replies: 6
Views: 5780

Re: Emulation and sync behaviour of a CRT monitor

Adding from the AD725.pdf data sheet: If no equalization or serration pulses are included in the HSYNC input there won’t be any in the outputs. Although sync signals without equalization and serration pulses do not technically meet the video standards’ specifications, many monitors do not require th...
by rv6502
Sat Nov 23, 2019 11:50 pm
Forum: Uzebox Emulator
Topic: Emulation and sync behaviour of a CRT monitor
Replies: 6
Views: 5780

Re: Emulation and sync behaviour of a CRT monitor

Writing emulators I find it easier to sync purely to the computer's audio using the cycle counters. So the audio becomes the speed governor. (if audio is disabled then I use a equivalent timer) The video is displayed using a small queue, regulated by computer's vsync or a timer, and doing a frame di...