Search found 50 matches
- Tue Nov 08, 2022 6:31 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
With $2000=$10 every BG CHR fetch is A12 high, and NT/AT fetches are A12 low, but since NT/AT only takes 4 dots the M2 filter is not fulfilled and we continue as if A12 remains high while in a repeating NT AT CHR CHR pattern. At the end of a scanline we get an extra NT NT, then an idle dot that's e...
- Tue Nov 08, 2022 2:49 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
It seemed to always fail test #2, which is what we expected.
The weird part is that it seemed to only fail if it happened to land on the right CHR bank. Otherwise, it would always pass. He did try it several times.
The weird part is that it seemed to only fail if it happened to land on the right CHR bank. Otherwise, it would always pass. He did try it several times.
- Tue Nov 08, 2022 9:33 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
Hmm, seems like this test ROM doesn't properly initialize MMC3 CHR banks? It displays either a bunch of garbage or a solid white screen most of the time, if mapper state is randomized in Mesen. Anywho, Bucketmouse tried it on his MMC3A board and, on boots where the right CHR banks happened to be loa...
- Fri Nov 04, 2022 7:55 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
Otherwise they are open source, which Blargg suggested checking if the error message isn't enough: source Ah, neat! I'll take a look at these. It looks like the scanline tests sync to an even vblank with CPU cycle precision, then they run with the counter starting with values that should either hav...
- Fri Nov 04, 2022 6:46 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
So, what I'm seeing in attempt #9 is that in Wario's Woods, the bottom scanline of the green grass will turn black about ~48 pixels before the end of the line, but only on some resets. That's the behaviour we're looking for, right? I don't have a real Wario's Woods cart to compare. I believe that s...
- Fri Nov 04, 2022 4:52 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
The IRQ logic really is kinda weird... I'll have to look into this in more detail later, now I'm really curious why that thing I wrote didn't work xD Oh, duh! I had misunderstood the counter's /reload signal as being asynchronous, but that wouldn't make much sense as it transitioning to 0 would imm...
- Fri Nov 04, 2022 4:05 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
If MAP04.MAP wasn't rebuilt maybe it should be removed from that zip, just so nobody's confused about the contents if they download it. Done! Anyway, I did try building it but the IRQ never seems to fire at all. :S Not sure what the problem was. Ah, that's unfortunate :/ Wish I had a PowerPak so I ...
- Thu Nov 03, 2022 6:35 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
Alright, upon studying the schematic further, I realized my filter logic wasn't quite right, lol. It generated positive edges at the same points as the real deal, I think , but turns out a lot of the IRQ logic is triggered by the negative edges of the filtered A12 instead. This is almost verbatim wh...
- Thu Nov 03, 2022 4:37 pm
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
So, it isn't quite the filter you suggested in your first post on this thread. I did try it like that, but never found a successful result with it. The implementation I had suggested at first is a fairly literal interpretation of the RE'd MMC3C schematic that Furrtek did by tracing decapped images ...
- Wed Nov 02, 2022 4:36 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
To be clear, if I had to choose between a hardware-accurate mapper and a robust mapper, I would take the latter. I'm trying to make something that runs existing games well and without problems. There is of course a place for a separate, more accurate version as well, if these things are in oppositi...
- Wed Nov 02, 2022 3:45 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
- Tue Nov 01, 2022 10:25 am
- Forum: NES Hardware and Flash Equipment
- Topic: PowerPak MMC3 fixes: accurate IRQ, MC-ACC submapper, iNES 2 CHR-RAM
- Replies: 51
- Views: 4661
Re: PowerPak MMC3 jitter fix for loopy's mapper
That's kind of a weird filter. Seems to me like it'd filter out negative A12 edges, but any positive edge would still trigger the counter. I believe an implementation closer to how the MMC3 handles it would be: reg [2:0] a12_delay_line; wire a12 = a12_delay_line == 0 && chrain[12]; always @(...
- Sun Dec 19, 2021 6:32 pm
- Forum: NES Music
- Topic: D[aw]PCM - A tool for editing and previewing DPCM samples in real time
- Replies: 0
- Views: 1195
D[aw]PCM - A tool for editing and previewing DPCM samples in real time
Hey, everyone! I've just published the first version of D[aw]PCM , a web tool that lets you import .wav files, process them and preview how they'll sound as DPCM in real time. This aims to improve the usual workflow of importing samples into Audacity, modifying them, exporting them, importing into F...
- Thu Jun 10, 2021 11:54 am
- Forum: General Stuff
- Topic: Becoming an FPGA Engineer
- Replies: 48
- Views: 13335
Re: Becoming an FPGA Engineer
Instead of trying non synthetisable command like "delay", try searching if your FPGA have built in feature for programmable delay. For example - the cheap popular EPM240 has and it can be turned as follows: pd.png BTW. The signal initial value assignment is not synthetisable in al chips, ...
- Tue Jun 08, 2021 7:25 pm
- Forum: General Stuff
- Topic: Becoming an FPGA Engineer
- Replies: 48
- Views: 13335
Re: Becoming an FPGA Engineer
Good to know that it doesn't make sense to do that. In what situation(s) could you correctly use a 'delay' or 'after' statement? Is that something for a different type of hardware? They're only useful for simulations. I believe some FPGAs have I/O blocks that allow for delaying a signal by a tiny b...