Clone cpu's that don't have duty cycles swapped?

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DutchC64
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Clone cpu's that don't have duty cycles swapped?

Post by DutchC64 »

Hi!

I was playing around with a bunch of clone cpu's and ppu's I have justnsitting here doing nothing and a famicom clone board that was sitting in my parts bin.

Right now I have it working with an um6527p cpu in it and a TA-02NP ppu.
The ppu was chosen because it can switch between 50 and 60hz depending on what state pin 16 is (+5v for 60hz or gnd for 50hz).
In 60hz the speed of thing is exactly like an ntsc console.

For fun I even hooked up the expansion audio and played the famicom version is castlevania 3 with the expansion audio, which is really cool.

But to get back on track....are there clone cpu's that don't have the duty cycles swapped?
If so, could you guys share the info?
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Eugene.S
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Re: Clone cpu's that don't have duty cycles swapped?

Post by Eugene.S »

TA-03NP1 (and probably TA-03N/TA-03NP) have correct duty cycles.
I have a few of TA-03NP1 chips only and can confirm this.
This is UA6527P-like timing chip ("pirate pal"/"dendy timing")

Known CPU revisions
Known PPU revisions

Here are recordings form custom-made dendy, based on Famicom PCB + stereomod,
TA-03NP1 CPU + UA6538 PPU, if you're need to verify:
Bucky O'Hare
Journey to Silius
Gremlins 2 - The New Batch
DutchC64
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Re: Clone cpu's that don't have duty cycles swapped?

Post by DutchC64 »

Cool, I have one of those cpu's :)
DutchC64
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Re: Clone cpu's that don't have duty cycles swapped?

Post by DutchC64 »

Eugene.S wrote: Sun Jun 13, 2021 7:23 pm TA-03NP1 (and probably TA-03N/TA-03NP) have correct duty cycles.
I have a few of TA-03NP1 chips only and can confirm this.
This is UA6527P-like timing chip ("pirate pal"/"dendy timing")

Known CPU revisions
Known PPU revisions

Here are recordings form custom-made dendy, based on Famicom PCB + stereomod,
TA-03NP1 CPU + UA6538 PPU, if you're need to verify:
Bucky O'Hare
Journey to Silius
Gremlins 2 - The New Batch

If you happen to have the ta-02 ppu lift pin 16 and connect it to +5 volt.
That way the system will run in 60hz and the speed and pitch of ntsc games will be perfect.

Do you happen to have a spare ta-02 ppu btw?
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TmEE
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Re: Clone cpu's that don't have duty cycles swapped?

Post by TmEE »

I got really excited about the 50/60Hz support on TA-02NP PPU, since I have it and I proceeded to do the necessary mods. The clone I have with that CPU actually connects pins 15,16 and 17 together and runs them to a VCC/GND spot but I separated them all and added a switch to control things individually and much to my dismay there was no 50/60 selection or other factors, it only changed far BG color.

Reset and power-on didn't seem to make any difference along with any of the 16 possible combinations. So it seems that not all TA-02NP are equal...
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krzysiobal
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Re: Clone cpu's that don't have duty cycles swapped?

Post by krzysiobal »

It must be TA-02NPB or maybe TA-02NP1.

BTW. Even if you get in possession of the PPU with mode select, switching pin 16 is just not enough. You need also proper CPU to keep correct CPU/PPU divider.
You could theoretically make separate clock for CPU and underclock/overclock it to achieve same CPU/PPU ratio as in NTSC, but that way the sound pitch will be different.

That's why many famiclones have places for soldering second crystal and jumpers, so that:
* When PPU = 60Hz, UA6527 CPU is used with 21 MHz clock,
* When PPU = 50Hz, UA6527P CPU is used with 26 MHz clock (the same as PPU's clock)
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TmEE
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Re: Clone cpu's that don't have duty cycles swapped?

Post by TmEE »

Wiki list should be updated then, it says just NP would have that feature but seems NP1 would be it then. NPB is listed as having 21/26MHz (which probably ties to PAL/NTSC too) select in addition to 50/60 select.

I am aware of the clock differences etc.

My favorite famiclone is a glob top, which has 50/60 select, PAL/NTSC select and 21/26MHz selects and correct duty cycles (and NTSC DPCM pitches). It made me think that this particular line of glob tops originated from the TA-0x chips instead of the UMC ones. It is often seen in the Terminator / Ending-Man type famiclone, especially old ones. (choosing NTSC with 26MHz clock will give BW image, as will choosing PAL with 21MHz clock)
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krzysiobal
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Re: Clone cpu's that don't have duty cycles swapped?

Post by krzysiobal »

TmEE wrote: Fri Jun 18, 2021 5:56 am Wiki list should be updated then, it says just NP would have that feature but seems NP1 would be it then. NPB is listed as having 21/26MHz (which probably ties to PAL/NTSC too) select in addition to 50/60 select.
Probably I wrote that, but can't rember right now if I had a NP chip that had the select feature or it was just NPB/NP1 and I skipped the last character for unknown reason. For sure I can tell that some day later I tested all the PPUs that I had and just single one had the select feature and it was NPB (others were UA6538, NP and other weird branded ones.
My favorite famiclone is a glob top, which has 50/60 select, PAL/NTSC select and 21/26MHz selects and correct duty cycles (and NTSC DPCM pitches). It made me think that this particular line of glob tops originated from the TA-0x chips instead of the UMC ones. It is often seen in the Terminator / Ending-Man type famiclone, especially old ones.
Terminators appear in many different revisions with around 50% rate of spotting the one with jumpers for selecting video mode. Though many of them also have some bug in the audio or audio opamp causing weird noises in games using DPCM.
(choosing NTSC with 26MHz clock will give BW image, as will choosing PAL with 21MHz clock)
That's probably because the frequency for color subcarrier for such configuration is similar but beyond specification and TV is just not capable of decoding the color information.

From currently manufactured models I can tell for sure that ZOGA NES has jumpers for PAL/NTSC selection. I can't tell anything about the duty cycle because I just can't recognize it by hearing and as far as I remember, there is no ROM that explicitly could test that.
DutchC64
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Re: Clone cpu's that don't have duty cycles swapped?

Post by DutchC64 »

krzysiobal wrote: Fri Jun 18, 2021 3:02 am It must be TA-02NPB or maybe TA-02NP1.

BTW. Even if you get in possession of the PPU with mode select, switching pin 16 is just not enough. You need also proper CPU to keep correct CPU/PPU divider.
You could theoretically make separate clock for CPU and underclock/overclock it to achieve same CPU/PPU ratio as in NTSC, but that way the sound pitch will be different.
With my clone ppu switchedto 60hz the speed and pitch of ntsc games are exectly like on my realy famicom, so switching to 60hz with the ppu is enouhg.

I even did the expansion audio mod on my 72 to 60 pin converter and my clone and now besides the mic on controller 2, it's like playing on my Famicom.

It's easy enough to add the mic on controller 2 on my clone and I have a set of spare Famicom controllers...so I might add it.
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krzysiobal
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Re: Clone cpu's that don't have duty cycles swapped?

Post by krzysiobal »

DutchC64 wrote: Mon Jun 21, 2021 2:41 pm so switching to 60hz with the ppu is enouhg.
Then try playing a game that relies on CPU/PPU ratio, like any race game with look from behind (F1 Race, Mach Rider) or game that has IRQ counter based on counting CPU cycles (for example Gimmick or other mapper 69) and see it wont work.
DutchC64
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Re: Clone cpu's that don't have duty cycles swapped?

Post by DutchC64 »

krzysiobal wrote: Mon Jun 21, 2021 2:45 pm
DutchC64 wrote: Mon Jun 21, 2021 2:41 pm so switching to 60hz with the ppu is enouhg.
Then try playing a game that relies on CPU/PPU ratio, like any race game with look from behind (F1 Race, Mach Rider) or game that has IRQ counter based on counting CPU cycles (for example Gimmick or other mapper 69) and see it wont work.
Will do
ludo110183
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Re: Clone cpu's that don't have duty cycles swapped?

Post by ludo110183 »

Hi everyone. Does anyone know where to fin a replacement for these two chips? They seem to be broken as my old DY-636-42 console has audio but no image (see picture)
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