Cannot communicate with GigaBlox Nano on our custom baseboard

BotBlox Hardware
1

I’m not seeing a successful 100 Mbps autonegotiated link between our hardware platform and the GigaBlox Nano switch. The link appears to go up then down soon thereafter, and it repeats this process over-and-over. The behavior is the the same when using either the Pico-Conn or RJ-Conn daughterboards. When the Pico-Conn is used we’re also using the included Picoblade-to-RJ-45 cable. If the RJ-Conn is used then we’re using a 12 inch COTS CAT6 cable. Both our hardware and the GigaBlox Nano switch are powered from the +12.0 V DC supply originating from the same battery power source so the ground references are more or less equal.

We have workaround paths and can remove the GigaBlox Nano switch from the platform, but I’d rather solve this issue and keep it in the system.

2

- Response from customer -

Some good news: we figured it out. It was an issue on my end with incorrectly valued termination resistors. I’d entered 49.9K instead of 49.9 and that was the root cause of the problem. For whatever reason other hardware could cope but the GigaBlox Nano was the one to show me the mistake.

After replacing with 49.9 ohm the link establishes without issue. From here we’re able to communicate with our Ethernet assembly.