Search found 1899 matches
- Sun Mar 17, 2024 9:06 am
- Forum: NESemdev
- Topic: ABS,X and (ZP),Y dummy read test ROM
- Replies: 19
- Views: 23878
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'...
- 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.
- Tue Mar 05, 2024 5:08 pm
- Forum: Newbie Help Center
- Topic: Help me understand this code...
- Replies: 3
- Views: 272
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...
- Wed Feb 28, 2024 5:36 am
- Forum: NESdev
- Topic: MMC5 and third pattern nametable
- Replies: 30
- Views: 2225
- Tue Feb 27, 2024 7:01 pm
- Forum: NESdev
- Topic: MMC5 and third pattern nametable
- Replies: 30
- Views: 2225
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...
- 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 ...
- Thu Feb 22, 2024 3:22 pm
- Forum: NESdev
- Topic: MMC5 and third pattern nametable
- Replies: 30
- Views: 2225
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 ...
- Sun Feb 18, 2024 8:44 pm
- Forum: NESdev
- Topic: MMC5 and third pattern nametable
- Replies: 30
- Views: 2225
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 ...
- 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...
- 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...
- Fri Dec 15, 2023 7:21 pm
- Forum: NESdev
- Topic: I can't to draw background correct!
- Replies: 25
- Views: 5112
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 ...
- Fri Dec 15, 2023 6:53 pm
- Forum: NESdev
- Topic: I can't to draw background correct!
- Replies: 25
- Views: 5112
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...
- Fri Dec 15, 2023 4:45 pm
- Forum: NESdev
- Topic: I can't to draw background correct!
- Replies: 25
- Views: 5112
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...
- Wed Nov 15, 2023 8:12 pm
- Forum: NESdev
- Topic: Question About the MMC1
- Replies: 25
- Views: 6118
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...
- Tue Nov 07, 2023 8:16 am
- Forum: NESemdev
- Topic: About boomberman nmi issue?
- Replies: 17
- Views: 2456
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...