Is an Asian NES Region free? Strange CIC Mod

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems.

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lidnariq
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Re: Is an Asian NES Region free? Strange CIC Mod

Post by lidnariq » Sun Sep 22, 2013 3:25 pm

First off, a CIC with pin 4 missing is as good as a CIC with pin 4 tied to VCC.
Second off, the modification given in this thread would work even with the CIC completely missing
Third off, if you're going to remove the CIC, don't bother to replace it, and instead just do either this mod, the one I posted here, or the one jims cool posted in that same thread.

nocash
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Re: Is an Asian NES Region free? Strange CIC Mod

Post by nocash » Fri Jan 29, 2021 3:45 am

lidnariq wrote:
Sat May 11, 2013 2:50 pm
The jumpers override the 4 MHz ceramic resonator, using it as an inverter to generate /RESET_BUTTON and then to tie that to /2A03_RESET_IN
I wasn't aware of that mod. Going by the photo with yellow wires (viewtopic.php?p=209346#p209346) ... the schematic would be as so?

Code: Select all

Pin6 (4MHz) --------------------- Pin 12+13 (NC?)
Pin? (not a CIC pin) ------------ Pin? (also not a CIC pin)
Is it really that easy???
Last edited by nocash on Sat Jan 30, 2021 12:59 am, edited 1 time in total.
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nocash
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Re: Is an Asian NES Region free? Strange CIC Mod

Post by nocash » Fri Jan 29, 2021 9:36 am

Oops, I got that wrong, the chip on the photo seems to have only 14 pins, whilst dip cic would have 16 pins. So I guess the 14 pin chip might be the hex inverter shown here?
https://hackaday.io/project/18301/galle ... 0dbbd13679
Or whatever.
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lidnariq
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Location: Seattle

Re: Is an Asian NES Region free? Strange CIC Mod

Post by lidnariq » Fri Jan 29, 2021 1:23 pm

nocash wrote:
Fri Jan 29, 2021 3:45 am
Is it really that easy???
Evidently, yes.

It's CIC pin 7 [LOCK CIC +RESET IN] to inverter input (74HCU04 pin 1, oscillator)
and then inverter output (74HCU04 pin 2/3) to CIC pin 9 [CPU/PPU -RESET IN]

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