UA6527P on NTSC Console

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trobby420
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Joined: Fri Jan 07, 2022 8:38 am

UA6527P on NTSC Console

Post by trobby420 »

I’m trying to figure out what is wrong with my console. Just a little backstory on the problem. I purchased a fan made PCB with all the components un soldered. I put everything together while using the old original CPU AND PPU. For some odd reason only SMB1 would work and not SMB3. I ended buying 2 clone chips from AliExpress. CPU UA6527P and PPU UA6528P. I popped out my old chips through in the new ones and things were worse off then before. Now I figured I screwed up when I actually received them and learned their the PAL version.

My question is, is there anyway to use the PAL chips on my fan made console, I’m assuming with a different clock?
lidnariq
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Re: UA6527P on NTSC Console

Post by lidnariq »

Yeah, those should need a 26.6MHz crystal instead. My understanding is that this frequency of crystal isn't particularly common, so you may need something different.

And you'll need a TV that can accept PAL. Or at least 50Hz video, if you're ok with it being black-and-white.


Braino. Read vortexion's posts below.
trobby420
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Re: UA6527P on NTSC Console

Post by trobby420 »

lidnariq wrote: Fri Jan 07, 2022 9:07 am Yeah, those should need a 26.6MHz crystal instead. My understanding is that this frequency of crystal isn't particularly common, so you may need something different.

And you'll need a TV that can accept PAL. Or at least 50Hz video, if you're ok with it being black-and-white.
I see. This is very insightful and I will have to think about it. Thanks!
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vortexion
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Re: UA6527P on NTSC Console

Post by vortexion »

I’m curious as to what UA6528P is for. I have read that it is a PAL-N version for Argentina, which uses a 3.582056 MHz PAL colour subcarrier.

The usual combinations for Famicom clones are:

UA6527 and UA6528 with a 21.47727 MHz crystal (6x NTSC)

UA6527P and UA6538 with a 26.6017125 MHz crystal (6x PAL)

UA6527 uses a /12 divider for the CPU clock and UA6528 uses a /4 divider for the PPU dot clock.

UA6527P uses a /15 divider for the CPU clock and UA6538 uses a /5 divider for the PPU dot clock.

Richard
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vortexion
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Re: UA6527P on NTSC Console

Post by vortexion »

Assuming UA6528P is for PAL-N, it would use a 21.492336 MHz crystal and could be paired with UA6527 (non P) which is the NTSC version. That’s because UA6527 has a /12 divider for the CPU clock, which would work here. UA6528P would have a /4 divider for the PPU dot clock and generate PAL colour.

The reason I’m unsure about this is that most Famicom clones I have come across from Argentina use TA-02NPN PPUs and TA-03NP CPUs, or the WDL version which I think is a rebranded version of the TA PAL-N chipset. I’ve never seen a Famicom clone from Argentina with a UMC chipset.

Richard
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