Famicom AV, PAL NES & Dendy chips decapsulation (progress!)

Discuss emulation of the Nintendo Entertainment System and Famicom.

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lidnariq
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres

Post by lidnariq » Mon Oct 30, 2017 11:50 pm

I'm having a very hard time finding whether any of these count as both "common" and "high priority". I can only think of things that would be deemed "points of curiosity" for the common ASIC mappers:
* MMC3: As far as we know, the two variants of the MMC3B are identical to the MMC3A and MMC3C — I wouldn't expect to find an interesting difference there. I think the only big question in my mind would be discovering the niggling details of how Nintendo implemented the PPUA12 edge detection.
* Namco's 108/109/118/119 are hopefully not too hard to find? It'd be interesting to figure out what causes the hazard is that Naruko identified when writing to $0000-$1FFF while executing from $8000-$9FFF.
* MMC1: I'd be idly curious to know how they implemented the MMC1 only paying attention to the first write of a RMW instruction.
* VRC2 and/or clones? Could be interesting to see what the SPI microwire interface looks like.

And then there's various rarer parts that have bigger question marks:
* Namco's 163: Could be interesting to see what the wavetable synthesizer DAC and logic look like. If you get a copy of 独眼竜政宗 = Dokuganryuu Masamune there's a bonus chip-on-board (the one immediately above the copper label "60-12") that's doing something Very Weird, not just being a bonus RAM that's used instead of the normal 163 RAM, but seemingly somehow disabling the normal 163 RAM?
* How exactly does RAMBO-1's IRQ work?
* why does Irem's G-101 have so many pins?

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rainwarrior
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres

Post by rainwarrior » Mon Oct 30, 2017 11:57 pm

The one I most care about is the VRC7.

Technically one has already been decapped but I'm still waiting for a decoding of the instrument ROM, which I understand requires some sort of chemical staining process to make visible?
https://forums.nesdev.com/viewtopic.php?f=9&t=12260

lidnariq
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres

Post by lidnariq » Mon Nov 13, 2017 7:26 am

Oh, another random one:

Taito's X1-017 (i.e. mapper 82) is connected to the NES's /IRQ line, but no game uses IRQs. It'd be idly interesting to see if (and how) the IRQ hardware is broken, or how one could be triggered.

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Eugene.S
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Re: Famicom AV, PAL NES & Dendy chips decapsulation

Post by Eugene.S » Fri Dec 01, 2017 1:53 pm

I've purchased Madara (VRC6b) and Lagrange Point (VRC7) from ebay.
So, i need to buy PAL NES CPU (RP2A07) and FDS (RP2C33)
for help this project: https://www.qmtpro.com/~nes/chipimages/

VEG
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres

Post by VEG » Tue Jul 31, 2018 5:00 am

It would be nice to look at UM6561 also. I know that some people don't like these NES-on-a-chip, but actually it is just further development of UA6527 and UA6538. For example, it is interesting how switching between PAL and NTSC is done in these chips.

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Eugene.S
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres

Post by Eugene.S » Wed Aug 01, 2018 4:25 am

I agree, but we still wait man who does decapsulation work

hacksquad
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Re: Famicom AV and Dendy chips decapsulation (progress!)

Post by hacksquad » Sat Mar 14, 2020 10:52 pm

hi there, sorry to reply on old post, i actually have MG-P-501 and MG-P'502

also i been testing the TA-02NP along side MG-P-501, no duty cycle issue sounds normal

The TA-02NP has been modded with NTSC and PAL switch, i leave the 26mhz xtal and it runs at PAL-60
Eugene.S wrote:
Thu Sep 03, 2015 6:12 pm
I've dug up the roots - all the rivers flocking to TXC corporation:

Seems TXC "developed" first clone-chips itself in late 80s, and it was:
MG-P-501 (CPU) photo1
MG-P-502 (PPU) photo2
I need to find these chips for testing, and make 100% sure about hybrid or ntsc timings they have.
I know that some MicroGenius consoles was pure NTSC (6527+6528), but some have (6527P+6538) hybrids.

TXC also developed original games, like Journey to the West (Asia) (Unl)

I'm waiting for original RP2C07-0 to decap it too.

lidnariq
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)

Post by lidnariq » Sat Mar 14, 2020 10:58 pm

Anything you can think to add to the descriptions here:
nesdevwiki:Known PPU revisions
and
nesdevwiki:Known CPU revisions
?

hacksquad
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)

Post by hacksquad » Sun Mar 15, 2020 11:48 pm

The TA-02NP Works with pin 17: Video mode: 50Hz (GND) / 60Hz (5V)

https://www.youtube.com/watch?v=7pEY6nnKFuo
lidnariq wrote:
Sat Mar 14, 2020 10:58 pm
Anything you can think to add to the descriptions here:
nesdevwiki:Known PPU revisions
and
nesdevwiki:Known CPU revisions
?

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Eugene.S
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)

Post by Eugene.S » Mon Mar 16, 2020 12:35 am

Still wait our decapper man, sorry. Anyway he promise will work on this project

hacksquad
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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)

Post by hacksquad » Mon Apr 06, 2020 8:40 am

iq701.jpg

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