Author Topic: Arduino Due SPI CLK output  (Read 2693 times)

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Offline tomshirvoTopic starter

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Arduino Due SPI CLK output
« on: January 14, 2015, 12:43:59 am »
I have been working on getting a external SPI flash Chip to work with the Arduino Due.

I am running it at 41Mhz as the chip only goes to 80Mhz and I can't set the clock to that.

Attached below is the output of the clock line on my scope.

So my question is, is the output of the clock look ok??
 

Offline dannyf

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Re: Arduino Due SPI CLK output
« Reply #1 on: January 14, 2015, 01:06:06 am »
Quote
is the output of the clock look ok??

What clock?
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Offline tomshirvoTopic starter

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Re: Arduino Due SPI CLK output
« Reply #2 on: January 14, 2015, 01:28:23 am »
Sorry, the SPI CLK that is on the 2*3 SPI header on the Arduino DUE
 

Offline c4757p

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Re: Arduino Due SPI CLK output
« Reply #3 on: January 14, 2015, 01:35:23 am »
What's the bandwidth of your scope? You need a fairly beefy one to see the shape of a 40 MHz square wave. (100 MHz won't cut it, and 50 MHz is right out.)
« Last Edit: January 14, 2015, 01:38:03 am by c4757p »
No longer active here - try the IRC channel if you just can't be without me :)
 

Offline tomshirvoTopic starter

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Re: Arduino Due SPI CLK output
« Reply #4 on: January 14, 2015, 01:40:37 am »
I have a DS1104Z so 100Mhz so looks like it won't cut it then.  :(

Thanks
 

Offline dannyf

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Re: Arduino Due SPI CLK output
« Reply #5 on: January 14, 2015, 01:59:01 am »
41Mhz SPI clk? What is your flash chip's fastest clock rate?
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Offline dannyf

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Re: Arduino Due SPI CLK output
« Reply #6 on: January 14, 2015, 02:10:26 am »
Aside from the clock rate, you want to make sure that there is sufficient swing. Most of those pins are ST so 0.2-0.8xVdd is all you need. Being sine (vs. square) has the added advantage of low emf emission.
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