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Overclocking Pinguino chip
25-12-2013, 08:38 PM,
#1
Overclocking Pinguino chip
Hi,

I'm using Pinguino to build a 3D spectrum analyser. Unfortunately it's not fast enough for the algorithms that have been implemented.

I was wondering if it's possible to overclock the chip frequency of Pinguino OTG32 by using another crystal. As far as I know the main clock frequency is derived from the crystal frequency. By increasing this frequency the calculation speed should increase as well.

The current frequency is 80MHz. Do you think I would be able to go up to 100MHz without having too much trouble with the delays?

Thank you,
Jack
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26-12-2013, 04:39 AM,
#2
RE: Overclocking Pinguino chip
Overclocking is a double edged sword, in my point of view.
You sure you cant optimize your code ?! With a more low level version, more "hands-on-hardware" kinda thing ?!
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28-12-2013, 12:00 AM,
#3
RE: Overclocking Pinguino chip
Overclocking often leads to unpredictable behaviour - I wouldn't do it.
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02-01-2014, 05:26 AM,
#4
RE: Overclocking Pinguino chip
(26-12-2013, 04:39 AM)iyahdub Wrote: Overclocking is a double edged sword, in my point of view.
You sure you cant optimize your code ?! With a more low level version, more "hands-on-hardware" kinda thing ?!

I'm not sure. I use some standard commands though... like analogRead(), digitalWrite(), pow(). The most time consuming part is the calculation of the frequencies using the Q-transform. The code is already been optimized more or less. You can find it here. Maybe you can find some functions that can be replaced by faster ones:
https://bitbucket.org/JoD/ledcube/src/15...?at=master

Thank you,
Jack
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02-01-2014, 11:06 AM,
#5
RE: Overclocking Pinguino chip
I've seen some people say 100MHz works at least on some boards.

You'd have to redo USB clock etc I suppose.

John
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02-01-2014, 11:23 AM, (This post was last modified: 02-01-2014, 11:27 AM by agolac.)
#6
RE: Overclocking Pinguino chip
(02-01-2014, 11:06 AM)pingotg Wrote: I've seen some people say 100MHz works at least on some boards.

You'd have to redo USB clock etc I suppose.

John

Why USB clock? It should stay at 48 MHz because it's USB standard...?
Dreaming in Code...
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02-01-2014, 04:15 PM,
#7
RE: Overclocking Pinguino chip
Isn't it derived from the xtal that you'd change?

John
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02-01-2014, 05:07 PM,
#8
RE: Overclocking Pinguino chip
(02-01-2014, 04:15 PM)pingotg Wrote: Isn't it derived from the xtal that you'd change?

John

If it is Olimex OTG board that JackGie is referring to when he says OTG32, then that board has external oscillator just for USB (32.768 MHz) and another 8Mhz that should be clocked.. ;o)
Dreaming in Code...
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04-01-2014, 09:36 AM,
#9
RE: Overclocking Pinguino chip
I don't think so. It has 8MHz that he'd change and 32KHz for RTC. I don't think the 32KHz is used for USB, is it?

There's an internal FRC clock but not usable for USB (other than detect).

John
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04-01-2014, 12:09 PM,
#10
RE: Overclocking Pinguino chip
(04-01-2014, 09:36 AM)pingotg Wrote: I don't think so. It has 8MHz that he'd change and 32KHz for RTC. I don't think the 32KHz is used for USB, is it?

There's an internal FRC clock but not usable for USB (other than detect).

John

I think it is powering USB because I've recently read a document that says about using 32.768 KHz for 48 MHz USB clock

This is the document

http://www.datasheetarchive.com/dl/Datas...011686.pdf

"The 48 MHz USB clock is usually generated by an
external 16 MHz crystal input to the System PLL.
However, to save space and cost, the 48 MHz USB clock
can also be generated by a 32.768 kHz crystal.
The jitter generated by both inputs is measured
independently and as of this publication date, the jitter
measurement results meet
USB Specification
(Revision 1.1). The results show full speed jitter
requirements using a 32.768 kHz crystal to generate the
48 MHz USB clock. The USB certification results are
provided at the end of this document"
Dreaming in Code...
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