Spurious CS glitches on CS line for imx6 SPI interface

[ToradexAI]

Hi, I’m the Toradex AI Assistant. The Toradex Support team will follow up with you shortly!

Did you like my answer?

---

Hi Glen,

Based on the information provided, it seems like you are experiencing spurious chip select (CS) glitches on the SPI interface of your Colibri iMX6DL module. Here are a few potential causes and suggestions to troubleshoot this issue:

1. Electrical Noise and Signal Integrity:

   • Ensure that the SPI lines, especially the CS line, are properly terminated and shielded to minimize noise and crosstalk.
   • Check the PCB layout for any potential issues that could cause signal integrity problems, such as long traces or improper grounding.

2. GPIO Configuration:

   • Since you are using GPIOs for CS lines, ensure that the GPIOs are correctly configured in your firmware. Any misconfiguration could lead to unintended toggling of the CS lines.
   • Verify that there are no conflicting configurations or unintended GPIO manipulations in your custom GpioLib.cpp and GpioLib.h files.

3. Software Timing Issues:

   • Check if there are any timing issues in your software that could cause the CS line to glitch. This could be due to race conditions or improper synchronization between different parts of your code.
   • Ensure that the SPI transactions are properly synchronized and that there are no overlapping operations that could cause the CS line to toggle unexpectedly.

4. SPI Driver and Firmware:

   • Review the SPI driver and firmware to ensure that there are no bugs or issues that could cause the CS line to glitch. This includes checking for any known issues or errata related to the SPI controller on the iMX6.
   • Consider adding additional logging or debugging information to help identify the root cause of the issue.

5. Power Supply Stability:

   • Ensure that the power supply to the Colibri module and the SPI devices is stable and free from noise. Power supply fluctuations can sometimes cause unexpected behavior in digital circuits.

6. External Interference:

   • Check for any external sources of interference that could be affecting the SPI lines. This could include other high-frequency signals or electromagnetic interference (EMI) from nearby components.

Given that you have already captured scope images showing the CS “blip” and subsequent clock cycles, it would be helpful to analyze these traces in detail to identify any patterns or correlations with other events in the system.

If the issue persists, you may want to reach out to Toradex technical support for further assistance, as they may have additional insights or suggestions based on their experience with the Colibri iMX6 module and similar issues.

Best regards,
[Your Name]

Please, also check if these links can help you solve your problem:

Overlay to activate SPI on CS1 don't work

I’m using Colibri-IMX6DL CoM in Aster V1.1 carrier board and tryng to change some characteristics of SPI (I need to reduce SPI clock frequency and use CS1). When I try to aply a devicetree overlay using torizoncore-builder I have a syntax error, but I really don’t know whats wrong with my (.dts) file. This is my .dts overlay file: /dts-v1/; /plugin/; / { compatible = "toradex,colibri_imx6dl"; }; &ecspi4 { fsl,spi-num-chipselects = <2>; cs-gpios = < &gpio5 2 GPIO_ACTIVE_HIGH &gpio5 4 GP…

2 Devices on 1 SPI Port, CS0 problem

Hi, it is my first post so please have mercy I searched the forums, but did not find an answer for my question. I am also a beginner in SoC programing. I am working with shift registers (74HCT595 for sending data and 74HC165N for reading data) and the spi bus on port 1. I am using the SPI library (in C). My problem is the cs0. It is wired as CS of the 74HCT595. Sending Data works fine. For reading data (74HC165N) I am using an custom gpio as PL (parallel load, no cs needed). I works t…

Colibri i.MX6 SPI Communication Failure Need Help.