Is there any ROM or program to test NOAC accuracy? I have few NOACs there and I want to compare their accuracy emulating the original NES objecticaly
Thanks
EDIT: A bit offtopic: is there any way to play a NSF on the NES using a EEPROM NROM cartridge?
socram8888 wrote:
Is there any ROM or program to test NOAC accuracy?
I'm not aware of any test ROMs made to test NOACs.
Quote:
is there any way to play a NSF on the NES using a EEPROM NROM cartridge?
Yes, depending on the size of the NSF. You have to code a simple program that initializes the NES and gives the user playback controls (next track and previous track, at least). You have to .INCBIN the NSF at the correct location and make use of the routines included in it. It is possible that someone has already made a basic program like that, so all you'd have to do is .INCBIN your NSF and assemble.
tokumaru wrote:
socram8888 wrote:
Is there any ROM or program to test NOAC accuracy?
I'm not aware of any test ROMs made to test NOACs.
I don't know of any specific NOAC tests either, but try blargg's tests if you can. And one common flaw in NOACs is incorrect waveforms on APU channels 1 and 2. These should be obvious from
playing a popular game, and my
volume test cycles through all channel 1 waveforms in the first four seconds so that you can hear any problem.
I have read (I don't remember where) that the NOAC (specifically, the "YoBo" NES clone) can't handle MMC5 games, like Castlevania III.
Does anyone know why?
Really shouldn't use "NOAC" and "Accuracy" in the same sentence. Most of them screw up the square duty cycles, and that is highly noticeable.
I already noticed a different waveform on all NOACs, and one of them (the worst I have) have a "clicking" when one of the channels plays something (not sure which one, though)
Well, I'm bidding for a Castlevania III cartridge, so I'll be able to test their compatibility with the MMC5 soon
PS: The 47k resistor mod for the PowerPak is the same mod needed to use the extra channels of the MMC5 on the NES?
PS2: A NTSC USA Castlevania would play fine on my PAL NES or I should get a PAL one instead? I'm unable to find any PAL version on eBay
socram8888 wrote:
PS2: A NTSC USA Castlevania would play fine on my PAL NES or I should get a PAL one instead? I'm unable to find any PAL version on eBay
You can usually test this by switching to PAL mode in some of the more accurate emulators (Nestopia, Nintendulator).
Looks like NTSC Castlevania checks for sprite 0 hit in a way that's incompatible with PAL. It runs each sprite 0 polling loop (looking for vblank end, and looking for sprite 0) up to 256 times before giving up, so it finishes the 256 checks too quickly for PAL mode.
edit:
To fix the PRG1 US rom for PAL mode, there is the loop waiting for sprite 0 to become clear.
Code:
07:F8C7:A2 00 LDX #$00
07:F8C9:E8 INX
07:F8CA:F0 07 BEQ $F8D3
07:F8CC:AD 02 20 LDA $2002 = #$50
07:F8CF:29 40 AND #$40
07:F8D1:D0 F6 BNE $F8C9
Change the second byte of the BEQ instruction to 00, and it deactivates the 256 check limit.
The Game Genie code is AEKNUAYA
Quote:
PS: The 47k resistor mod for the PowerPak is the same mod needed to use the extra channels of the MMC5 on the NES?
Yes, but Castlevania III doesn't use extra channels (as opposed to it's own Japanese version).
I'm pretty sure the reason MMC5 and 4-screen mirroring games doesn't work on famiclones is that CIRAM /CE is internally tied to CHR /A13 and the both aren't brough to the cart edge. This effectively would lead all games who tries to use internal RAM for something else than nametables OR games that use their own RAM/ROM as nametables to a huge fail.
The MMC5 might also be notworking because the fetch order is likely different, and this screw it's scanline counter up, including all it's "automatic bankswitching" features.
Thanks for the theory, Bregalad.
The designers of the YoBo could have avoided the first issue, I would think, if they had thought their design through a bit better.
The second issue I can see being real troublesome. Does a NOAC PPU really work differently from a real PPU?
I wonder how the NOAC got its PPU core then.
I'm aware of at least 4 different types of NOAC.
1. Discrete clones, copies of the CPU and PPU separately. Seem to be accurate, probably exact clones of the IC's die. The old clones.
2. NOAC, used on TriStar/Super 8, seemed pretty good
3. NOAC with shitty sound (reversed duty cycles)
4. NOAC with enhanced graphic modes etc.
I don't think they're all from the same manufacturer (#1 is UMC), I don't know though about the others. Some of these companies have development tools online, assemblers, emulators, and other interesting stuff.
That first type of clone is pretty good, they even work with the PowerPak. I haven't tested the MMC5 though.
Now that the mask work rights and patents on the NES CPU and PPU have thoroughly expired, I wonder how much it would cost to have a chip fabbed with exact gate-for-gate copies of the CPU, PPU, two 2kx8 SRAMs, and the various other circuitry to make an accurate NOAC.
I only know one NOAC manufacturer: "KASUN KA3552A". Next to that text it's another label: "6561-18p" (isn't that the UMC DIP chip number?), manufactured 2005/3/20
I'm unable to find any information related to that manufacturer on the internet
Other NOAC, a GLK (one of these that look like a computer, this one looks like a laptop), has a model number "662C" manufactured "2005/01/19". There's a difference between that NOAC and the other I've seen: the glob-top chip is the double in size. For me, this has the best video and audio quality. The noise channel is a bit louder, but for the rest it's like a original NES
I have another NOAC too, in a portable console named "MyWico Portable". I've bought that one in Toys'R'us for 20€. It has really advanced features: advanced video mode (with prerenderized graphics!), one-bus mode, RGB (for the LCD screen) and composite video (video out), and the most awesome: PCM playback. There are THREE FULL SONGS with voices and everything! It's awesome for a NOAC!
I can upload photos of any of these if anyone wants them
PS: Thanks Dwedit for that piece of code!