Search found 1537 matches

by Quietust
Sun Jul 05, 2020 10:21 am
Forum: NES Hardware and Flash Equipment
Topic: Standardizing symbols for PCB mirroring pads
Replies: 18
Views: 366

Re: Standardizing symbols for PCB mirroring pads

Whatever the symbols may be, the V symbol ideally should not be identical to the H symbol rotated by 90 degrees.
by Quietust
Fri Jul 03, 2020 6:14 am
Forum: Newbie Help Center
Topic: issue with super mario bros sprite 0 xy, when reading $2007
Replies: 4
Views: 149

Re: issue with super mario bros sprite 0 xy, when reading $2007

At the very least, you need to write to $2000 again and set the bottom 2 bits to point at the expected "base" nametable.
by Quietust
Thu Jun 25, 2020 10:30 am
Forum: NESemdev
Topic: Nintendulator log change
Replies: 12
Views: 9437

Re: Nintendulator log change

I've just made an additional update to the nestest reference log to fix 2 things: 1. The "PPU" column now displays the scanline number first and the pixel number second, because I realized it was confusing to have it the other way around (i.e. it was like showing Seconds,Minuntes instead of Minutes,...
by Quietust
Fri Jun 19, 2020 10:30 am
Forum: NESemdev
Topic: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k
Replies: 2
Views: 650

Re: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

The part that I wonder about the most: how is the game going to access PRG @ 0x40000 - 0x43fff? The fifth bit is usually masked out on roms under 512k w/MMC1. I'm guessing that it expects all of PRG 40000-47FFF to be mapped to CPU $8000-$FFFF if the MMC1 resets in 32KB bank mode. Do you think the c...
by Quietust
Thu Jun 18, 2020 5:20 am
Forum: NES Hardware and Flash Equipment
Topic: Help! CopyNES plugins for Mappers 176, 268, and extended CNROM (128KB CHR)
Replies: 2
Views: 566

Re: Help! CopyNES plugins for Mappers 176, 268, and extended CNROM (128KB CHR)

As for mapper 268: A CopyNES can dump at most 32 MiB minus 256 bytes in one go, so it's best to dump 16 MiB in each of two goes, and only when outputting to UNIF or headerless files. I need to update my plugin for that, also later. Technically, the limit is 16MB minus 256 bytes per packet , and the...
by Quietust
Sun Jun 14, 2020 7:17 am
Forum: NES Hardware and Flash Equipment
Topic: What is 'Mapper Ctrl' Mirroring?
Replies: 4
Views: 422

Re: What is 'Mapper Ctrl' Mirroring?

Hey guys, So I've read about horizontal and vertical mirroring, what exactly those mean I'm not too sure about but what confuses me even more is when I see games on the NESCartDB which say "Mirroring: Mapper CTRL" What does that mean? It just means that nametable mirroring is Mapper C on tr o l led...
by Quietust
Sat May 09, 2020 1:03 pm
Forum: Newbie Help Center
Topic: .bank .org question
Replies: 5
Views: 955

Re: .bank .org question

From what I understand, the .bank 0 defines an 8 kb chunk of memory, and then we're telling it to select the chunk starting at CPU address $8000, and write all the following code starting at that CPU address. But what is the point of .bank 0, if we're going to just tell the CPU where to start putti...
by Quietust
Fri May 08, 2020 6:56 am
Forum: NESemdev
Topic: Visual 2A03 Update
Replies: 13
Views: 2430

Re: Visual 2A03 Update

New feature for Visual 2A03: audio output display. There are now 5 boxes to the right of the memory table which display waveforms for each of the builtin sound channels (square 0, square 1, triangle, noise, PCM); the first 4 are scaled vertically by a factor of 3 (so that they aren't extremely tiny)...
by Quietust
Thu May 07, 2020 4:46 pm
Forum: NESemdev
Topic: ISC Instruction
Replies: 2
Views: 871

Re: ISC Instruction

A gets set to 53 in both cases, the result is the same, but my instruction sets the C flag whereas the official log doesn't. I'm scratching my head a little bit on this one. The subtraction is resulting in borrow ($40 - $EB), and that should clear the carry flag (because it's the opposite of how it...
by Quietust
Thu May 07, 2020 2:23 pm
Forum: NES Hardware and Flash Equipment
Topic: Multicart doesn't work on famicom
Replies: 12
Views: 1898

Re: Multicart doesn't work on famicom

Ice Man wrote:
Thu May 07, 2020 11:32 am
Might want to post pictures of the PCB front and back as well. :)
This might also tell us if the cartridge is using 3.3V chips instead of 5V ones, which might possibly cause problems with a standard Famicom.
by Quietust
Wed May 06, 2020 2:58 pm
Forum: NESemdev
Topic: DCP Indirect Indexed
Replies: 2
Views: 841

Re: DCP Indirect Indexed

The 8 cycle timing you saw on the wiki includes the page crossing because DCP is a Read-Modify-Write instruction (being based on DEC) and thus always takes the extra cycle for page crossing. Read-Modify-Write instructions (SLO, SRE, RLA, RRA, ISB, DCP) # address R/W description --- ----------- --- -...
by Quietust
Tue May 05, 2020 6:04 pm
Forum: NESemdev
Topic: Visual 2A03 Update
Replies: 13
Views: 2430

Re: Visual 2A03 Update

With a bit of experimenting, I've figured out what's going on - the loop happens when the PPU starts drawing Sprite pixels on top of a blank Background. It was very briefly shorting the Background and Sprite pixel data together, and since Ground "wins" in NMOS, the sprite pixels were becoming blank ...
by Quietust
Tue May 05, 2020 10:31 am
Forum: NESdev
Topic: IRQ nesting due to OAM DMA
Replies: 9
Views: 1345

Re: IRQ nesting due to OAM DMA

The 6502 wasn't designed to be used that way, hence the name, non maskable . "Non-maskable" has nothing to do with interrupts overlapping - it has to do with the fact that NMI ignores the "Interrupt Mask" flag (while IRQs respect it, allowing you to ignore them when you don't want to deal with them).
by Quietust
Mon May 04, 2020 6:43 pm
Forum: NESemdev
Topic: Visual 2A03 Update
Replies: 13
Views: 2430

Re: Visual 2A03 Update

I've done a round of updates to reorder the transistors driven by pclk0 (edit: and also pclk1), and with an update to the builtin test program, I've confirmed that all 8 sprite render units appear to be functional, at least with 8x8 sprites at Y=0 on the first few scanlines (the X counters and CHR s...
by Quietust
Sat May 02, 2020 8:20 pm
Forum: NESemdev
Topic: Visual 2A03 Update
Replies: 13
Views: 2430

Re: Visual 2A03 Update

Somehow, I managed to get through nearly all of the 2C02 (except for pclk1/pclk2), though in the process I somehow managed to introduce a rather severe OAM corruption bug when writing to $2003. Of course, considering that writing nonzero values to $2003 is known to cause corruption, but it's not sup...