8710A Reset Design Flaw

Created by: sslupsky

There is an issue in the way the reset circuity on the BBB resets the 8710A ethernet PHY.

When coming out of reset, the 8710A can end up in an indefinite state as a result. This is problematic because you can loose the ability to communicate with the BBB occasionally and it requires a physical reset to clear the problem. For a remote system if a difficult to reach location this creates a major problem.

We have found that you can hack the current pcb (Rev B or Rev C) and disconnect the reset line from the 8710A. Then, hack a wire from the 8710A reset pin to a GPIO on the BBB. Now, when the ethernet PHY hangs it can be reset by asserting the GPIO pin.

I would like to recommend a revision to the PCB to address this issue. At the moment the reset trace near the 8710A is on an inner layer and not easily accessible. It would be a big help if the trace was more easily accessible. It would be an even bigger help if there was a jumper and a couple pads.

We would be happy to contribute the firmware driver we developed for this.