How to avoid electrical perturbation on Colibri?


I’m working on the following equipment:

  • Colibri Evaluation Board V3.2B
  • iMX7D module

On this board, I have a Linux 4.1.35-v2.7b1 build with Yocto using version 2.7 of Toradex repo.
I’m doing test on SPI, using ecspi3. Its pins are the following:

  • SODIMM 86: CS
  • SODIMM 88: CLK

I’m watching signals with an Oscilloscope. I can see that perturbations occured on all of the signal. Some of them are more than 2V. (On a 3.3V signal, it is quite important!!)

I can see perturbations even if SPI is not plugged to another device. So they must be comming from the Toradex board.

Does anybody got an idea on what could causes all the perturbation. And how can i remove or at least lower them.

Thank you.

We are not aware of any noise issue on the SPI interface that is produced by the iMX7 module. Can you provide us more information how you have measured the noise? Can you send the scope diagram and a picture in which it is possible how you measure the noise? Where do you attach the ground for measuring the noise? What peripherals do you have attached to the Evaluation Board?