Search found 141 matches

by SusiKette
Sun Mar 14, 2021 9:40 am
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

Have you seen my YM2413 emulation code (https://github.com/nukeykt/Nuked-OPLL), it is based on VRC7 die analysis as well. Would be nice to cross check our findings. Sure. I'm not very good at reading C++ code so reading it might take some time. By the way; Were you able to figure out the connection...
by SusiKette
Thu Mar 11, 2021 2:50 pm
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

I just found out how the VRC7 disables the channels 7-9. I marked where the different channel's carriers and modulator's were at a given time (eg when phase generator outputs ch1 modulator's phase), what each module gets as input and what they output. I was able to use that to compare different inpu...
by SusiKette
Fri Mar 05, 2021 3:21 pm
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

While looking around the die, I found that the data output multiplexer (which also is used to dump the instruments) has one output option that outputs only two bits. These seem to output serial data from different modules of the chip. Bit 0 outputs lower 9 bits of phase (there are 18 bits total and ...
by SusiKette
Sun Feb 21, 2021 10:36 am
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

I took a look at the timing logic and I realized that the counter that keeps track of the shift register position actually only resets every 18 cycles instead of 9 cycles like I originally thought. The timing sequence itself is 18 cycles long. The shift register is writable only on the first 9 cycle...
by SusiKette
Thu Feb 18, 2021 3:13 pm
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

Ben Boldt wrote:
Thu Feb 18, 2021 2:48 pm
Do you see any possible detection of register $9008 on the VRC7 die?
I have checked the address decoder already, but I might need some elaboration on what you mean.
by SusiKette
Mon Feb 15, 2021 5:25 pm
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

Re: VRC7 discoveries

The official YM2413 datasheet claims 84 master clock cycles. Since the VRC7 runs at twice the 2A03 CPU clock ... 42. Oh? I have only seen a datasheet of YM2413 where the only thing given in cycles is the reset pulse width. Do you know where to find this datasheet that list this info? Also, accordin...
by SusiKette
Mon Feb 15, 2021 3:56 pm
Forum: NESemdev
Topic: VRC7 discoveries
Replies: 19
Views: 8411

VRC7 discoveries

I recently got back to inspecting the die shot of VRC7 and I found out few things that might be relevant to emulating the chip (or just in general interesting observations). I don't think any of these are mentioned on the wiki page either (or anywhere else as far as I have read). While VRC7's master...
by SusiKette
Fri Dec 25, 2020 4:05 am
Forum: NES Music
Topic: Is it possible to mix DMC samples in software?
Replies: 5
Views: 3602

Is it possible to mix DMC samples in software?

I'm not sure if there are mappers that can map CHR-RAM to ROM area, but I was wondering if there is a way to mix two DMC samples in software an put the result in CHR-RAM in area where the DMC channel can play it? If there is a way, I don't think simply adding the samples together would work, which i...
by SusiKette
Fri Dec 25, 2020 2:55 am
Forum: NESemdev
Topic: Emulator with disassembly capability
Replies: 4
Views: 3274

Re: Emulator with disassembly capability

I don't remember mesen having a disassembly feature (unless it was added just recently). I don't mean disassembly as in begin able to see the code in the debugger. I mean it as in disassembling the code into text files (and maybe chr and dmc files too).
by SusiKette
Thu Dec 24, 2020 3:56 am
Forum: NESemdev
Topic: Emulator with disassembly capability
Replies: 4
Views: 3274

Emulator with disassembly capability

If one doesn't exist yet, I was thinkin of making one. Basically you play the game and it logs stuff and when you are ready you can disassemble the ROM. Some basic features that are needed probably are: Code/data logger Address/lable logger Branch logger Basic debugger Hex editor The branch logger c...
by SusiKette
Sun Dec 06, 2020 9:36 am
Forum: Newbie Help Center
Topic: MMC5 extended RAM and fill mode
Replies: 5
Views: 3053

Re: MMC5 extended RAM and fill mode

The wiki also mentio s that the expansion RAM can only be written while PPU is rendering. Is this right? And does this mean rendering as in rendering begin enabled from PPU registers or while a frame is begin rendered?
by SusiKette
Sat Dec 05, 2020 10:58 am
Forum: Newbie Help Center
Topic: MMC5 extended RAM and fill mode
Replies: 5
Views: 3053

MMC5 extended RAM and fill mode

According to the wiki MMC5 has the PRG RAM at $6000-$7FFF. When you are using the extended RAM modes 0 or 1, what parts of the PRG RAM are used for these features? Mode 1 can also be used as a extended nametable. How does this work with the additional attribute data used in that mode? The wiki menti...
by SusiKette
Sun Nov 29, 2020 1:45 pm
Forum: NES Music
Topic: Preparing DMC samples
Replies: 5
Views: 4637

Re: Preparing DMC samples

A low-pass isn't necessary unless the original sound has a lot of higher frequencies you don't want. Converting the sample usually does have a low-pass like effect on louder frequencies, but it might not completely filter them out. Although due to the bit crushing that happens you will still get som...
by SusiKette
Sat Nov 28, 2020 11:37 am
Forum: NES Music
Topic: Preparing DMC samples
Replies: 5
Views: 4637

Preparing DMC samples

I was curious if anyone here know how you should prepare a wav file to be converted as a DMC sample to get the best result. One trick that I know for percussion samples is that you add some white noise the sample and it'll hide the "crackling" sound you get at low volumes. Are there any recommendati...
by SusiKette
Sat Nov 28, 2020 5:34 am
Forum: NES Music
Topic: I finally got a way to fix the triangle channel bug in Ufouria!
Replies: 16
Views: 11516

Re: I finally got a way to fix the triangle channel bug in Ufouria!

The NSF for Hebereke (and probably Ufouria too) has two versions of the title screen theme. One with the triangle channel and one without. I was wondering if both exist in the ROM as separate tracks or if the other was added to the NSF manually.