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Topic: Clocking source for audio synthesis (Read 178 times) previous topic - next topic

harish017

Unlike, Uno which has an inbuilt XTAL crystal oscillator, do arduino due has such external clock syncing to audio core libraries?. I usually, use internal oscillator for synthesis although it has some timing inaccuracies. Can I use 84 mhz dedicated to my audio engine removing the 32 khz internal oscillator?. Regard to atmel datasheet, it says I have to use 12pf capacitance grounded to XIN of crystal oscillator. Is it worth clocking with crystal people?. If its the case, I may also need to sync crystal with teensy

Grumpy_Mike

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do arduino due has such external clock syncing to audio core libraries?
No.

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Can I use 84 mhz dedicated to my audio engine removing the 32 khz internal oscillator?
Sorry no idea what that means.

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Regard to atmel datasheet, it says I have to use 12pf capacitance grounded to XIN of crystal oscillator.
That is to get the proper loading on the crystal and oscillator in order for the oscillator to start reliably.

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I may also need to sync crystal with teensy
You can not sync a crystal to anything, you sync things to the crystal.

Paul Stoffregen

#2
Jul 12, 2016, 12:07 am Last Edit: Jul 12, 2016, 12:07 am by Paul Stoffregen
You can not sync a crystal to anything, you sync things to the crystal.
Oh really?

http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm

Usually it's done with a Varactor diode in place of one or both of the capacitors.

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/varactor.html

Not that this is really relevant to the difficult-to-parse question.  Or maybe it is?  Hard to tell...

harish017

Yes, I heard we can also connect a jumper between one end of I/O to other end, but not sure if its reliable method. The reason why I am choosing crystal oscillator is for its timing accuracy, although my concern is if all audio libraries functions as usual inspite of clocking with the crystal oscillator. Some people like the inaccuracies that give different results. So, what can be better from the pro point, internal oscillator or crystal oscillator for a CLK source?

Paul Stoffregen

Your questions lack context.

Design decisions are made within the context of a project with specific details.

harish017

I don't think so, it must rather be misinterpreted. The fact that to generate pwm waves, we would require a source. I mean that. Isn't that irrelevant to the context?

Paul Stoffregen

I do not understand what you want.  This latest message adds a little more information, that it involves generating PWM waves, which wasn't mentioned anywhere previously.

Whatever you're trying to ask, it's not clear at all.  Nobody can answer a question they do not understand, and this question is a jumble of works without specifics, without a clear picture of what the goal is.  I can't help.

harish017

I just want to create PWM waves that's my goal. But my question is about clocking. Like, what source should I use for clocking is the intended question inbetween middle of arguments. Also with the PWM I am going to do audio synthesis.

Grumpy_Mike

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Also with the PWM I am going to do audio synthesis.
So you need the PWM frequency to be high, preferably ultrasonic and at least twice the sample rate.

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what source should I use for clocking
The system clock. That is what the timer registers are set up to use. There is no advantage in using anything else.

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