Search found 70 matches

by MrD
Sun Jan 24, 2021 11:18 am
Forum: Megadrive/Genesis
Topic: 68K Memory access
Replies: 9
Views: 11197

Re: 68K Memory access

Most carts don't actually. The console has an internal address decoder that drives two chip selects the cart can use !CE0 (asserted for the bottom 4MB of the address space) and !TIME (asserted from A13000 to A130FF). Of course, you can ignore those and do your own decoding, but I wouldn't recommend...
by MrD
Sun Jul 26, 2020 4:47 pm
Forum: Demos
Topic: Game Raccoon - Open Hardware/Software SD Card Cart
Replies: 3
Views: 7090

Re: Game Raccoon - Open Hardware/Software SD Card Cart

Couldn't have done it without you. :)
by MrD
Sun Jul 26, 2020 1:20 am
Forum: Demos
Topic: Game Raccoon - Open Hardware/Software SD Card Cart
Replies: 3
Views: 7090

Game Raccoon - Open Hardware/Software SD Card Cart

I've completed the website for the Game Raccoon SD Card flash cart. :) https://www.mrdictionary.net/gameraccoon/revision1/gameraccoonlogo7_raccooncute_shadow_placedcaption400.png http://www.mrdictionary.net/gameraccoon/ https://www.mrdictionary.net/gameraccoon/imgout/IMG_6950_2000wide-295x220_1.jpg ...
by MrD
Thu Jul 09, 2020 2:34 pm
Forum: Megadrive/Genesis
Topic: How prone is Sonic 2 to bugs?
Replies: 0
Views: 75346

How prone is Sonic 2 to bugs?

I just encountered for the second time in ten years a strange effect in (ordinary, real) Sonic 2. https://sendvid.com/49xl5hyv (apologies for the choice of site but it was what I had to hand) The game over music started playing in the middle of the Oil Ocean Zone Act 2 for no reason, the timer froze...
by MrD
Mon Jun 29, 2020 11:27 pm
Forum: Cartridge
Topic: Designing MD sdcard flashcart for fun, advice?
Replies: 37
Views: 49519

Re: Designing MD sdcard flashcart for fun, advice?

There are two pages I need to write for my website for Revision 1: I've got the blog page which is a mess of events and thoughts as they happened roughly reorganised into topics, and the Technical Report which only includes the final description of the cart, the approaches, the manufacturing files, ...
by MrD
Mon Jun 29, 2020 11:23 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

Sonic mods compatibility spreadsheet for the games that were previously marked as Crashed: https://docs.google.com/spreadsheets/d/e/2PACX-1vS44e4oGkZ6fZOAymYN4r0WWIS6k-LXX9nm3d2zFtgpqtTlqS4JHDLYGdPgm6XQWpHnVTvcybG0ywWt/pubhtml I just need to get to writing up the website for my cart now and it's don...
by MrD
Thu Jun 25, 2020 2:36 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

Just when I thought this year couldn't get any stranger... Thanks! I don't recall seeing myself any games that list ABC as A TRIGGER, B TRIGGER, C TRIGGER in the option mode, but I can definitely imagine it. I still feel somewhat justified as that describes B as being the main trigger button for act...
by MrD
Wed Jun 24, 2020 4:25 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

Edit - I'm putting together a new spreadsheet of Sonic mods changed by the IO fix, and I'm trying Griel's Quest again. It turns out that on the level select menu, for some bonkers reason buttons A and C are 'confirm' and B is 'back', which is outrageous! Uuuuuh, what else do you expect them to be? ...
by MrD
Tue Jun 23, 2020 11:10 am
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

I hope I haven't offended you Stef in singling out SGDK. I don't mean anything as a criticism, I'm just interested in how everything works. Edit - I'm putting together a new spreadsheet of Sonic mods changed by the IO fix, and I'm trying Griel's Quest again. It turns out that on the level select men...
by MrD
Mon Jun 22, 2020 9:28 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

If BlastEm barfs at a hack you can probably assume the issue is the hack :​P And yeah, games rely on telling apart between cold and warm boot not only because of the init skip stuff (not sure why Sega insisted on that ), but also because most games don't reset the options when you press the Reset b...
by MrD
Sun Jun 21, 2020 2:05 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

Now lets take for example that your menu code enables TMSS (by writing 0 to TMSS register, which BTW is the power on state) before starting the game ROM but left I/O control ports, the vast majority (all?) of games won't boot because of TMSS which will always be skipped by the above, because your m...
by MrD
Sat Jun 20, 2020 1:24 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

With IO reset and Z80 reset added, compatibility for demoscene and homebrew goes up from 50% to 90%ish. :D Thank you! All the SGDK-based software works now: all the Retro Souls games and the Resistance demos. My verdict: https://i.imgur.com/KzolCTZ.jpg I'm not convinced it's necessary... despite it ...
by MrD
Fri Jun 19, 2020 2:10 pm
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Re: Most compatible way to jump to game image on hardware - making my own cart

Thank you. :) Hmm, I haven't cleared the IO control registers. I don't see how that would cause games to not boot... ohhhhh I see. Right! Now that is interesting, yes!

Also it's good to know that interrupts should begin disabled.
by MrD
Fri Jun 19, 2020 8:26 am
Forum: Megadrive/Genesis
Topic: Most compatible way to jump to game image on hardware - making my own cart
Replies: 21
Views: 28248

Most compatible way to jump to game image on hardware - making my own cart

My Game Raccoon Revision 1 SD card flashcart is working great. :) Here's a video of the current menu interface (sadly lacking an animated raccoon mascot for the loading screns). You can read about R0 and R1 in the GR thread in the Cartridge subforum. https://cdn.discordapp.com/attachments/4996436313...
by MrD
Thu May 28, 2020 10:36 pm
Forum: Megadrive/Genesis
Topic: Alternative to Vasm assembler?
Replies: 27
Views: 31919

Re: Alternative to Vasm assembler?

Awesome, thanks. I didn't understand that part of the docs.