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SPI on Intel Edison Mini Breakout not working

DSimm1
New Contributor I
1,659 Views

I'm running Linux ubilinux 3.10.17-yocto-standard-r2 # 7 SMP PREEMPT Thu Feb 26 09:57:06 UTC 2015 i686 GNU/Linux on my Intel edison with a mini breakout board (NOT the arduino board!) and am having a devil of a time getting SPI to function correctly.

I am currently attempting to use mraa as the library, but am still getting no good result. I'm using the Node.js portion of mraa right now, but I have written a small c++ program, which fails in the same way.

If I simply put a jumper between J17-12 and J-18-11 and write a series of bytes out via SPI, they a=do, indeed, get echoed back correctly. So I know I have toe right pins, However, once I bring SCLK and CS into the picture, things go pear-shaped. CS is J17-10 and SCLK is J17-11, according to the data sheet, but once I actually hook my SPI board up via all these connections, SPI ceases to function correctly. At least my board doesn't react well to it.

I can hook the same board to an Adafruit FT232-H SPI dongle and write/read SPI to/from it just fine, but attempting to do the same writes/reads via the edison fails. (All return values are 0xFF and they should not be).

As we are all aware, the documentation for the edison is ... umm ... sorely lacking, so trying to debug this is difficult.

5 Replies
Carlos_M_Intel
Employee
200 Views

Hi DavidGS,

Have you checked the signals with a logic analyzer or oscilloscope?

Are you using pull-up resistors?

I suggest you to also contact http://www.emutexlabs.com/forum/index EmutexLabs. They are the experts in this image.

Regards,

Charlie

DSimm1
New Contributor I
200 Views

Using pull-up resistors? No, I'm not. Do I need to? There is zero documentation on this of course so I'm flying blind.

Carlos_M_Intel
Employee
200 Views

Hi DavidGS,

You could be having some problems related to noise in the signal or maybe with the timing between the device and the board. I suggest you to check the signals with a logic analyzer or oscilloscope to verify the behavior of the signals.

Regards,

Charlie

LYuha
New Contributor III
200 Views

DavidGS

How fast are you setting your SPI device to run at? What frequency are you using? Try a low frequency like 10khz and move up. see if the signal gets worse as it gets faster

DSimm1
New Contributor I
200 Views

I have tried every speed. Finally, after much posting, and debugging, Intel admitted that the SPI on the Intel Edison Mini breakout essentially doesn't work. Why they never said this right off the bat, thus saving me hours/days of work, is beyond me.

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