Clarification on Apalis iMX8QP PCN


I’ve been going through the PCN document for Apalis iMX8QP v1.1D. Change #2 appears to concern the onboard KSZ9131 ethernet PHY, but I’m unsure what ‘R51’ and ‘assembly state’ refer to.

I tried consulting the KSZ9131 datasheet, and I’m assuming the above pertains to device mode selection, where device mode was configured to 1111 in v1.1D and will be configured to 1110 in v1.1E instead.

From the PCN document, it seems like this change is transparent to the end user in terms of both hardware and software. Is my understanding valid?

Hatsy Rei

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Hello Hatsy Rei,

I understand you’re seeking clarification on the changes related to the KSZ9131 ethernet PHY in the Apalis iMX8QP v1.1D, specifically about ‘R51’ and ‘assembly state’, and their impact on end users.

Your interpretation regarding the device mode selection for the KSZ9131 ethernet PHY is accurate. The change from a configuration of 1111 to 1110 indeed pertains to the device mode settings, which are typically used to define the operational mode of the PHY at power-up. These settings can influence aspects such as speed, duplex mode, and auto-negotiation.

The term ‘R51’ likely refers to a specific resistor on the Apalis iMX8QP board that is used to set these configurations. The ‘assembly state’ could be indicating whether this resistor is placed or not, and its value, which in turn determines the mode configuration bits for the PHY.

As for the impact of this change, if the PCN document states that it is transparent to the end user, it means that from both a hardware and software perspective, this modification does not require any action or adjustment on the part of the user. The functionality and performance of the ethernet interface should remain consistent with previous versions, despite the change in configuration settings.

It’s important to ensure that any software or firmware interacting with the KSZ9131 PHY does not rely on the specific configuration that was altered. However, given the transparency of the change, it’s unlikely that typical applications would be affected.

Best regards,
Toradex AI Assistant

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

Apalis Evaluation Board | Toradex Developer Center.

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The R51 is a resistor used for Ethernet PHY strapping in the Apalis iMX8 modules. Earlier versions of these modules utilized the KSZ9031 PHY, and strapping for the 1111 mode was appropriate. However, when the KSZ9031 PHY was replaced with the KSZ9131 PHY, the 1111 mode, although still functional, is marked as ‘reserved’ and should no longer be used. Removing R51 will change the strapping mode to 1110. This modification does not require any software or hardware adjustments