Search found 2298 matches

by TmEE co.(TM)
Tue Jul 17, 2018 8:42 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 1
Views: 46

Re: Cart Design Questions

You need full level conversion, resistors aren't going to do anything but current limiting. For single direction stuff you could get away with voltage dividers but signal edges will get poor. For bidirectional signals you'll definitely want actual chips doing the thing. And for power rails you need ...
by TmEE co.(TM)
Wed May 23, 2018 9:31 pm
Forum: Megadrive/Genesis
Topic: Color analysis between different emulators/editors
Replies: 5
Views: 362

Re: Color analysis between different emulators/editors

The video DAC part is figured out pretty much. There's 17 taps on a long resistor structure and each tap is turned on with a control signal to enable certain level on the color channel output. 15 MD mode levels plus two SMS mode exclusive levels.
by TmEE co.(TM)
Thu Apr 26, 2018 6:17 pm
Forum: Megadrive/Genesis
Topic: Struct maros/syntax and naming conventions
Replies: 6
Views: 476

Re: Struct maros/syntax and naming conventions

I do stuff like that :

OffsetName EQU 124

MOVE.W OffsetName(A0), D0

EDIT: Exactly what you try to avoid... lol. I don't know of any better solution.
by TmEE co.(TM)
Wed Apr 04, 2018 6:30 pm
Forum: Megadrive/Genesis
Topic: Game loops and Vertical Blank interupts
Replies: 29
Views: 1188

Re: Game loops and Vertical Blank interupts

I poll for VBL bit in the VDP in main loop and I also set a flag in the frame interrupt. If main loop sees that the flag is set after all game logic it can assume slowdown has happened and act upon it, when flag isn't set the logic ended before frame did.
by TmEE co.(TM)
Sat Mar 17, 2018 7:41 am
Forum: SGDK
Topic: Rescomp colour conversion
Replies: 3
Views: 257

Re: Rescomp colour conversion

I just do 255/34 in my tools and it works for linear and the nonlinear ramp too.
by TmEE co.(TM)
Fri Mar 16, 2018 6:06 am
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 2443

Re: Where do I start? I'm seeking technical documents.

Just for code I have couple old things that can be looked at : My first game on MD, very poor code : http://www.tmeeco.eu/SMD/GBMD11S.RAR Pong game that doesn't use RAM at all : http://www.tmeeco.eu/BitShit/PONG!RAM.ASM And for some less terrible stuff here's a disassembly of the TMSS ROM I made a w...
by TmEE co.(TM)
Tue Mar 06, 2018 5:59 pm
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 2443

Re: Where do I start? I'm seeking technical documents.

Interrupts are auto-acknowledged on MD, there's no need to read the status port to get the next interrupt. Also on Z80 side, IRQ lasts entire line and if your handler finishes early it'll be called again due to it.
by TmEE co.(TM)
Tue Feb 27, 2018 3:54 pm
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 2443

Re: Where do I start? I'm seeking technical documents.

Only SMS/GG actually use the first index in a visible way, no other console does. So you're limited to using backdrop to make use of those first 4 indexes of each palette.
by TmEE co.(TM)
Tue Jan 16, 2018 10:18 pm
Forum: Super 32X
Topic: Cartridge bigger than 32Mbits ?
Replies: 27
Views: 14624

Re: Cartridge bigger than 32Mbits ?

Your bank writes goes to high byte (D8....D15), you'll have to do MOVE.W #$bb00, ($A130xx) where bb is your bank number to get the number go to low byte (D0...D7) which the mapper responds to. Little-endian vs Big-Endian business.
by TmEE co.(TM)
Mon Dec 11, 2017 11:00 pm
Forum: Demos
Topic: Xeno Crisis
Replies: 3
Views: 588

Re: Xeno Crisis

I do wish the arenas get bigger and scroll around like Alien Syndrome. Single screen stages make things pretty underwhelming...
Music side of things has me interested though. Good luck ~
by TmEE co.(TM)
Tue Oct 17, 2017 12:13 pm
Forum: Blabla
Topic: 3D printed cart....new paths ?
Replies: 5
Views: 749

Re: 3D printed cart....new paths ?

For small scale stuff it does make sense to 3D print things. Mechanically they can be good but you got to design things appropriately. If you need hundreds of cartridges then 3D printing is gonna be on the verge of not cheap plus it also takes a long time to make those carts. For thousands you can d...
by TmEE co.(TM)
Thu Oct 12, 2017 4:38 pm
Forum: Blabla
Topic: Make a wish / What if : Genesis
Replies: 21
Views: 1600

Re: Make a wish / What if : Genesis

There's no sharing of VRAM access patterns (MD and SMS access patterns are night and day, SMS mode using patterns identical to real SMS VDP), no compatible data formats (everything is completely different, GFX, tilemaps, sprite list) or the rendering process (identical to real SMS in SMS mode). Not ...
by TmEE co.(TM)
Wed Oct 11, 2017 2:34 pm
Forum: Blabla
Topic: Make a wish / What if : Genesis
Replies: 21
Views: 1600

Re: Make a wish / What if : Genesis

Writing is the part that isn't useful though, I got to pass stuff to Z80 side and almost never read back any responses. Workaround is using cart RAM, that's not subject to access issues from Z80. SMS compatibility is not a problem, NMI never happens in MD mode and YM IRQ never happens in SMS mode. Y...