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PostPosted: Tue Apr 16, 2019 5:16 pm 
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Is there a better way to generate 21.47727M waveform:

Is this one OK?
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PostPosted: Tue Apr 16, 2019 5:56 pm 
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Define "better".
Are 21.477MHz crystals easily purchased?
Are they series or parallel type?
Can you instead just buy a crystal oscillator instead of the bare crystal?
Is that not too much more expensive?

There are at least a dozen ways to get a clock out of a crystal. The one you want to use depends a lot on what the context is. Regardless, specifically in the case of the NES, for proper color rendition the clock supposedly needs to be within 3ppm of exact, so you'll need to include a trimmer capacitor.

If you have the right crystal type, you may as well use the same one-transistor schematic as the Famicom (top center) or NES (center left).

(this was my 8253rd post, the programmable interval timer of the original IBM PC)


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PostPosted: Tue Apr 16, 2019 6:53 pm 
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lidnariq wrote:
Define "better".
Are 21.477MHz crystals easily purchased?
Are they series or parallel type?
Can you instead just buy a crystal oscillator instead of the bare crystal?
Is that not too much more expensive?
(this was my 8253rd post, the programmable interval timer of the original IBM PC)


It's very easy to order.
And also very cheap.(about 0.03~0.04 USD)
I want use "quartz crystal resonator".

I see, I wil try to find the way from schematic .,


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