Prototyping baseboard for G400-D

Hi to all,

I am currently prototyping a customized baseboard for G400-D; based on the G400-HDR breakout board schematic.

Unfortunately, I have met with the issue of the SOM resetting itself whenever the built-in Ethernet is being initialized on my customized baseboard. During this situation, it seems like the physical layer chip is not visible to the MPU on the SOM.

This issue is not present when the G400-HDR breakout board is used. The SOM also seem to function properly when the built-in Ethernet is not initialized.

May I check if anyone has come across this issue? Your clarification on this problem is greatly appreciated.

Thank you.


My guess is that you do not have sufficient power. The PHY draws a lot of power when used and this is causing a voltage drop, which in turn resetting G400.

Welcome to the community.

I ran into similar issue recently, too. Adding large capacitors on every corner of the board solved the problem.

If this is a power related issue, may we know watis and Simon what kind of opwer supply you are using? I am currently designing a g400 based board and I am using a recom R78B switching regulator.

We used a generic LDO previously, but now switched to XCL214 DC/DC converter (to reduce power consumption).

Hi all

Watis and myself are working on the same board.

We have been checking back and fro between the schematic and pcb routing to see what went wrong, but we came back empty.

I have done the following test today.

  1. I jumper out the supply from the LDO and use it to power the G400-HDR breakout board . Every think work out fine. This suggest that the LDO is providing sufficient supply to the G400D.

  2. I have soldered on 10 uF caps at each of the inputs of the VCC. Same issues.

Simon: What are the value of capacitors you played with?

Simon, Gus: Is it possible we compare notes on the pinout used for the G400D.