Search found 1899 matches

by Quietust
Sun Mar 17, 2024 9:06 am
Forum: NESemdev
Topic: ABS,X and (ZP),Y dummy read test ROM
Replies: 19
Views: 23886

Re: ABS,X and (ZP),Y dummy read test ROM

Two of the dummy read tests are using mirrors of $2002, but one is using $2004. $2004 reads are something I suspect could cause emulators (and even real hardware) issues, but it doesn't look like it actually uses the value read from $2004, so I have no idea why it reads from there. I'm guessing it'...
by Quietust
Sat Mar 09, 2024 7:17 am
Forum: NES Hardware and Flash Equipment
Topic: Boot Up delay solution to prevent slowly configuration from FPGA.
Replies: 6
Views: 449

Re: Boot Up delay solution to prevent slowly configuration from FPGA.

If you're going to use weak pullups, it'd probably be easier to put them on the PRG ROM's upper address lines to enforce a fixed bank, then put your reset code in that bank and have it poll a readable mapper register and wait until it's done initializing.
by Quietust
Tue Mar 05, 2024 5:08 pm
Forum: Newbie Help Center
Topic: Help me understand this code...
Replies: 3
Views: 273

Re: Help me understand this code...

I have a few questions about some code. I am currently studying a dissembled Legend of Zelda. There is a part of the code that states: Variable RoomAllDead := $34D First what does the := represent Second what does the $34D mean? Is this Hex, Binary, or Dec? The := is presumably how the expected ass...
by Quietust
Wed Feb 28, 2024 5:36 am
Forum: NESdev
Topic: MMC5 and third pattern nametable
Replies: 30
Views: 2228

Re: MMC5 and third pattern nametable

Bregalad wrote: Wed Feb 28, 2024 1:28 am "A" and "B" should be swapped for this statement to be correct.
Fixed.
by Quietust
Tue Feb 27, 2024 7:01 pm
Forum: NESdev
Topic: MMC5 and third pattern nametable
Replies: 30
Views: 2228

Re: MMC5 and third pattern nametable

If "ReadPPUMem()" is reading from the currently mapped CHR banks, then you need to switch those CHR banks beforehand so it reads the right ones. If your PPU code follows the same cycle-by-cycle memory fetch pattern that the real chip does (which it looks like it does), then you want to swi...
by Quietust
Thu Feb 22, 2024 3:46 pm
Forum: NESdev
Topic: Running mapper 206 as MMC3
Replies: 8
Views: 476

Re: Running mapper 206 as MMC3

They seem to work perfectly as mapper 4 in some emulators (e.g. FCEUX), but not others, in which they have severe graphical glitches (e.g. Nintendulator). Curiously, the graphical glitches seen in Nintendulator will occur in FCEUX if I set the mirroring to vertical , which suggests to me that it's ...
by Quietust
Thu Feb 22, 2024 3:22 pm
Forum: NESdev
Topic: MMC5 and third pattern nametable
Replies: 30
Views: 2228

Re: MMC5 and third pattern nametable

How do you do MMC5 8x16 sprites in your emus? My MMC5 code listens for writes to $2000 and stores D5 (val & 0x20) in a "SpriteMode" variable, and if it's on, then every scanline at cycle 256 it switches to the Sprite banks and at cycle 320 it switches to the Background banks. I could ...
by Quietust
Sun Feb 18, 2024 8:44 pm
Forum: NESdev
Topic: MMC5 and third pattern nametable
Replies: 30
Views: 2228

Re: MMC5 and third pattern nametable

Sprites don't use "nametables" - I assume you're asking about the MMC5's ability to handle 2 sets of pattern tables, one for Sprites (using $5120-$5127) and one for Background (using $5128-$512B). If that's the case, the answer is that it automatically switches based on what it thinks the ...
by Quietust
Wed Feb 07, 2024 7:06 am
Forum: NES Graphics
Topic: moving stuff
Replies: 7
Views: 1080

Re: moving stuff

I'm having trouble finding the 'extract_mm_nes' ... I'm running windows unfortunately You need to download the "2.7.0 Tools" package and then run "scummvm-tools-cli --tool extract_mm_nes [-o outputdir] <infile.PRG>" (where 'infile.PRG' is the original ROM image with the iNES hea...
by Quietust
Mon Feb 05, 2024 2:46 pm
Forum: NES Graphics
Topic: moving stuff
Replies: 7
Views: 1080

Re: moving stuff

If you're specifically working with the non-Japanese version of Maniac Mansion, you should know that the entire game is written using the SCUMM engine, with the Room resources having been modified to store NES-style data. I'd actually recommend using the ScummVM "extract_mm_nes" utility to...
by Quietust
Fri Dec 15, 2023 7:21 pm
Forum: NESdev
Topic: I can't to draw background correct!
Replies: 25
Views: 5116

Re: I can't to draw background correct!

forever: LDA #%00011110 ; set up mask to be enabled background and sprites STA PPUMASK LDA #%00010000 ; disable nmi and enable background STA PPUCTRL JSR load_screen ; load tiles in memory by address $2000 LDA #%10010000 ; enable nmi STA PPUCTRL JMP forever You need to reread and follow tokumaru's ...
by Quietust
Fri Dec 15, 2023 6:53 pm
Forum: NESdev
Topic: I can't to draw background correct!
Replies: 25
Views: 5116

Re: I can't to draw background correct!

I tried everything. The code is not working. Last code this. forever: LDA #%00011110 STA PPUMASK LDA #%00010000 STA PPUCTRL JSR load_screen LDA #%00011110 STA PPUMASK LDA #%10010000 STA PPUCTRL JMP forever Could you add some comments to that code to explain exactly what you're expecting it to do? B...
by Quietust
Fri Dec 15, 2023 4:45 pm
Forum: NESdev
Topic: I can't to draw background correct!
Replies: 25
Views: 5116

Re: I can't to draw background correct!

Maybe attach a binary so we don't have to build it ourselves... I can already see that there is a mistake in the boot code, it's only waiting for the vblank flag to be set once. Need to wait for it twice to work correctly on real hardware, but that shouldn't affect working on emulators. Yes, I atta...
by Quietust
Wed Nov 15, 2023 8:12 pm
Forum: NESdev
Topic: Question About the MMC1
Replies: 25
Views: 6123

Re: Question About the MMC1

Is there a reason you want to use MMC1? Almost all other mappers are better choices. I used the MMC1 because it's the simplest ROM mapper I could use for such a small task, like I said in my original post. I promise you, despite MMC1 having the lowest mapper number, it is far from the "simples...
by Quietust
Tue Nov 07, 2023 8:16 am
Forum: NESemdev
Topic: About boomberman nmi issue?
Replies: 17
Views: 2462

Re: About boomberman nmi issue?

If a CPU instruction can contain multiple clock cycles to trigger a write or read memory trigger, what should be done with the remaining cycles? And how to determine "appropriate"? With the 6502, every cycle corresponds to a memory access (and vice-versa). And by "appropriate" I...