We're connecting an Overo Earth to a custom baseboard. We want to use the Gumstix for Ethernet, SDIO, and GPIO. So our baseboard design copied the Tobi design for Ethernet. But it's not working. We aren't seeing anything come out the Ethernet lines, not even the link integrity test pulses.

We're using the same LAN 9221 chip specified on the Tobi schematic. We didn't use an RJ45 connector, and so that means we didn't use the Halo HFJP1-S003-S1L12 part. Instead, we used a Pulse H1102NL 10/100Base-T transformer and an 8-pin Harwin connector. We included the same passives and ESD protection, and the same EEPROM specified.

We're using the bootloader and kernel images from the Gumstix website. When we boot the Overo on the Tobi board, we can clearly see the TPO+/- lines being driven periodically by the LAN chip, with a differntial pulse in that time frame. On our baseboard, the lines do change periodically, but the pulse never appears. Would an improperly configured Ethernet controller behave this way?

The ethtool binary works on both cases, so we know that we're able to have the OMAP processor communicate with the LAN controller. What should we be investigating? Or are there other components needed to make the Toby Ethernet design work?