About the APU channels' frequency

Discuss emulation of the Nintendo Entertainment System and Famicom.

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Boolean
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Joined: Thu Jan 02, 2014 7:58 am

About the APU channels' frequency

Post by Boolean »

I know the square wave programmable timer is clocked by one APU cycle(equals two CPU cycles), the triangle wave programmable timer is clocked by one CPU cycle.
How about the noise wave programmable timer?
Thank you.
Ten years passed. Hope that nesdev will be better in next ten years. :beer:
lidnariq
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Re: About the APU channels' frequency

Post by lidnariq »

Only the triangle wave runs at CPU frequencies. Everything else sound related runs at CPU÷2.
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cpow
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Re: About the APU channels' frequency

Post by cpow »

lidnariq wrote:Only the triangle wave runs at CPU frequencies. Everything else sound related runs at CPU÷2.
Yeah this wasn't immediately obvious to me either. The div-by-two is hidden in the LUTs for the noise and DPCM length counters.
Boolean
Posts: 87
Joined: Thu Jan 02, 2014 7:58 am

Re: About the APU channels' frequency

Post by Boolean »

Thank you. I get it.
Today is Mon Apr 14, 2014. I successfully get the info, via wiki, about the term timer which describes the APU channels' frequency.
Ten years passed. Hope that nesdev will be better in next ten years. :beer:
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