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Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres
Posted: Mon Oct 30, 2017 11:50 pm
by lidnariq
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?
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres
Posted: Mon Oct 30, 2017 11:57 pm
by rainwarrior
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
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres
Posted: Mon Nov 13, 2017 7:26 am
by lidnariq
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.
Re: Famicom AV, PAL NES & Dendy chips decapsulation
Posted: Fri Dec 01, 2017 1:53 pm
by Eugene.S
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/
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres
Posted: Tue Jul 31, 2018 5:00 am
by VEG
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.
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progres
Posted: Wed Aug 01, 2018 4:25 am
by Eugene.S
I agree, but we still wait man who does decapsulation work
Re: Famicom AV and Dendy chips decapsulation (progress!)
Posted: Sat Mar 14, 2020 10:52 pm
by hacksquad
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+65
28), but some have (6527
P+65
38) hybrids.
TXC also developed original games, like
Journey to the West (Asia) (Unl)
I'm waiting for original RP2C07-0 to decap it too.
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Sat Mar 14, 2020 10:58 pm
by lidnariq
Anything you can think to add to the descriptions here:
nesdevwiki:Known PPU revisions
and
nesdevwiki:Known CPU revisions
?
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Sun Mar 15, 2020 11:48 pm
by hacksquad
The TA-02NP Works with pin 17: Video mode: 50Hz (GND) / 60Hz (5V)
https://www.youtube.com/watch?v=7pEY6nnKFuo
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Mon Mar 16, 2020 12:35 am
by Eugene.S
Still wait our decapper man, sorry. Anyway he promise will work on this project
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Mon Apr 06, 2020 8:40 am
by hacksquad
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Thu Jan 07, 2021 11:34 am
by jcarlos
Good. I have a NINTENDO NES-001 to which the PPU RP2C07A-0 has broken down, although it cannot be seen with the naked eye, and I want to replace it with the clone UA6541 from the manufacturer UMC. Can someone tell me if I will have any problems in the exchange ? Thanks and best regards.
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Sun Apr 25, 2021 9:05 am
by Leugrim
jcarlos wrote: ↑Thu Jan 07, 2021 11:34 am
Good. I have a NINTENDO NES-001 to which the PPU RP2C07A-0 has broken down, although it cannot be seen with the naked eye, and I want to replace it with the clone UA6541 from the manufacturer UMC. Can someone tell me if I will have any problems in the exchange ? Thanks and best regards.
Could you do it? Wasn't it better to use the ua6538?.
Re: Famicom AV, PAL NES & Dendy chips decapsulation (progress!)
Posted: Sun Aug 21, 2022 4:32 am
by za909
Necrobump but I have some valid questions here.
Does this affect any other parts of the system, like CPU or PPU clock rate or any dividers?