Verdin iMX8M Plus, USB_1_ID alternate options?

Technical Support
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Verdin iMX8M Plus Quad 4GB WB IT V1.1B

Hello!

I am wanting to implement an RMII interface from the Verdin SoM on a custom carrier board. So, I need to connect the RMII Ref CLK and have these options:

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Pin 38 is awfully far away from the rest of the RMII signals and makes it very difficult to length-match that trace. I’d like to use pin 161. However, we are already using the USB_1_ID pin for our OTG port. I see this note for the USB1 interface:
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My question is: Since the USB_1_ID pin is a “regular GPIO”, am I able to reassign that function to any other available GPIO, so that I may use pin 161 as the RMII ref CLK?
Is there anything else I need to consider regarding either the RMII or USB1 interface when doing this?

Thanks!

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

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Hello,

Yes, the USB_1_ID pin on the Verdin iMX8M Plus can indeed be reassigned. In version 1.1 of this module, the SoC pin SD1 RESET B is utilized as the USB ID, and it offers GPIO2_IO10 functionality. This setup facilitates dynamic role switching between host and client modes on the USB_1 (OTG) interface.

Here are some important considerations to keep in mind:

  1. Software Compatibility: The automatic role switching feature is supported and functional when using version 5.6.0 or newer of the Embedded Linux BSP. This ensures that your system can handle the dynamic switching effectively.

  2. Custom Carrier Boards: If you are implementing this change on custom carrier boards, it is advisable to include an assembly option for using pin 161 as the USB ID. This helps maintain compatibility with other Verdin modules.

  3. Device Tree Modifications: To properly configure the pin multiplexing, modifications to the device tree are necessary. This step is crucial to ensure that the reassignment works as intended.

After making these changes, I recommend thoroughly validating the USB functionality. Proper testing is essential as USB configuration can significantly impact system stability and performance.

If you have any further questions or need additional guidance, feel free to ask.

Best regards,
Toradex AI Assistant

3

Yes, you can do it, but you will need to update the USB connector properties and pinmux settings in your Device Tree.

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