Search found 252 matches

by nitro2k01
Fri Oct 20, 2023 9:04 am
Forum: General Stuff
Topic: Whatever happened to Martin Korth?
Replies: 13
Views: 3251

Re: Whatever happened to Martin Korth?

The auth dialog shows "webseite wurde kompromittert/gehacked/infiziert", which seems to roughly translate to "Website was compromised/hacked/infected" Hopefully this is just temporary and things get fixed. Interesting. It's not showing that message to me. I just see a standard a...
by nitro2k01
Fri Oct 20, 2023 7:53 am
Forum: General Stuff
Topic: Whatever happened to Martin Korth?
Replies: 13
Views: 3251

Re: Whatever happened to Martin Korth?

Currently, http://problemkaputt.de (with or without https) asks for http authentication. Does anyone know what's up?
by nitro2k01
Mon Aug 07, 2023 2:01 am
Forum: GBDev
Topic: Fixing ROMs for EMS 64 GB Smart Card USB
Replies: 338
Views: 226455

Re: Fixing ROMs for EMS 64 GB Smart Card USB

I've produced patches as per the previous poster's requests. I've also added some notes for each game. These are mostly my internal notes, but maybe they're useful for someone. If you want clarification about anything said below, please ask. I created the patched ROMs using BGB and a hex editor for ...
by nitro2k01
Sat Jun 10, 2023 9:27 pm
Forum: SNESdev
Topic: Questions about the PAL/NTSC controller incompatibility
Replies: 3
Views: 2127

Re: Questions about the PAL/NTSC controller incompatibility

Follow-up: The same Reddit poster returned with an update . The issue was related to using a 3rd party controller. The hypothetical explanation then becomes a lot less esoteric. Likely, the id bits (the bits that are clocked after receiving the button state) is different from a genuine controller. T...
by nitro2k01
Tue May 30, 2023 6:16 pm
Forum: GBDev
Topic: I have a stupid question about the chip select and reset lines on a game boy cartridge
Replies: 15
Views: 3365

Re: I have a stupid question about the chip select and reset lines on a game boy cartridge

A few issues. Your cartridge signals are mislabeled. 3 = /WR 4 = /RD 5 = RAM /CS 30 = /RESET There's really no reason for /RD and /WR to have pullups in this circuit. They're always driven to either 0 or 1 by the mux so the pullup essentially does nothing. 74HC238 is the wrong mux. It's active high ...
by nitro2k01
Sat May 06, 2023 4:59 am
Forum: SNESdev
Topic: Questions about the PAL/NTSC controller incompatibility
Replies: 3
Views: 2127

Questions about the PAL/NTSC controller incompatibility

It's kind of a well known effect that non-PAL SNES controllers don't work with PAL consoles. FullSNES describes this effect as follows : SNES PAL vs NTSC Controllers SNES PAL consoles are passing CK1, CK2, STB lines through diodes (the diodes are located on the controller connector daughterboard ins...
by nitro2k01
Mon Apr 10, 2023 5:06 am
Forum: SNESdev
Topic: Is the following ChatGPT-generated SNES code legit?
Replies: 27
Views: 4651

Re: Is the following ChatGPT-generated SNES code legit?

Even if it did use WAI instead of WDM there, it'd still be wrong because DMA halts the CPU until it's finished. The WAI instruction would just stall (possibly forever) until a completely unrelated interrupt happened instead. It's wrong, but it's a sensible idea if you tried to dream up a fanfic sol...
by nitro2k01
Sat Apr 08, 2023 7:15 pm
Forum: SNESdev
Topic: Is the following ChatGPT-generated SNES code legit?
Replies: 27
Views: 4651

Re: Is the following ChatGPT-generated SNES code legit?

SNES AYE wrote: Sat Apr 08, 2023 12:37 am

Code: Select all

    ; wait for transfer to complete
    WDM
Not only is this wrong, but it's wrong in an interesting way. I wonder if ChatGPT was scanning a 65816 instruction table and interpreted the description for WAI as belonging to WDM because WDM followed immediately after WAI in the table/list.
by nitro2k01
Sat Apr 01, 2023 4:53 am
Forum: SNESdev
Topic: Snes APU01 revision with missing diode
Replies: 4
Views: 2145

Re: Snes APU01 revision with missing diode

It appears that D1 and D2 are connected in parallel and that they're just different options for the same component, depending on what they could buy the cheapest for a given production run. Unless D2 is faulty, no action should be required. You can check D2 in diode mode using a multimeter in diode ...
by nitro2k01
Wed Mar 22, 2023 10:59 pm
Forum: SNESdev
Topic: 65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)
Replies: 11
Views: 1303

Re: 65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)

There is only normal open bus, and it decays fairly quickly (roughly 2 vsyncs) Even 2 vsyncs seems suspiciously long tbh. Back of the envelope calculation: If we take 2 vsyncs to be 30 ms and use this is an RC time constant and assume (the resistive part of) the bus impedance is 1 Mohm (probably on...
by nitro2k01
Wed Mar 22, 2023 4:48 am
Forum: SNESdev
Topic: 65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)
Replies: 11
Views: 1303

Re: 65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)

The explanation I'd previously seen is from Anomie and claims this: "The theory is that the S-CPU chip has something called a "Memory Data Register" or MDR, which stores the value for every read/write. When you attempt to read from unmapped memory, no new value is supplied for this r...
by nitro2k01
Tue Mar 21, 2023 1:47 pm
Forum: SNESdev
Topic: 65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)
Replies: 11
Views: 1303

65816/SNES open bus/MDR mystery, (re: the latest RGMEx video)

Today's question comes about from a detail in a video from the excellent Youtube channel Retro Game Mechanics Explained about an advanced Super Mario World speedrun technique that leverages arbitrary code execution. The video goes into great detail about how this technique works, but the question I'...
by nitro2k01
Wed Mar 08, 2023 4:19 am
Forum: GBDev
Topic: I have Stupid questions about the vblank signal off the DMG's lcd
Replies: 7
Views: 2855

Re: I have Stupid questions about the vblank signal off the DMG's lcd

If the vblank is disabled in the gameboy's LCD Status register, or the display is completely disabled in the gameboy's LCD Control register, does this stop the vertical blank signal to the LCD, or does it simply disable interrupt routing from the ppu to the cpu? Everything stops. When you restart, ...
by nitro2k01
Tue Mar 07, 2023 5:26 pm
Forum: GBDev
Topic: Are there any games that use the MGB bootrom handoff value?
Replies: 7
Views: 1906

Re: Are there any games that use the MGB bootrom handoff value?

Nice work. I analyzed a couple of them manually and so far only false positives. "Lolo no Daibouken (Japan).gb" Has a bug: Writes to LCDC when it meant to read from it to check if LCDC is disabled or enabled. No intentional differences, and likely no material differences between modes. &qu...
by nitro2k01
Tue Mar 07, 2023 4:33 pm
Forum: GBDev
Topic: I have a stupid question about the chip select and reset lines on a game boy cartridge
Replies: 15
Views: 3365

Re: I have a stupid question about the chip select and reset lines on a game boy cartridge

Let me make that a 99%. There should be no cases where the cartridge drives the data bus while /RD is high. So if all other lines are connected in parallel and you gate the /RD signal, that should get you there. However, you also want to gate the /WR signal for completeness, otherwise cartridge woul...