Finding GPIO3_21 on the BBB schematic

I'm looking at a schematic dated Mar 21, 2014, rev C. I'm trying to find where the McASP0 external clock generator, on page 3, goes. It references pp. 6, 10, and 11, but I can only find it on p.4 (which references only p. 11), and p. 11, P9 header, pin 25 (which references only p. 4).

You are correct. The caption on P3 is incorrect. McASP0 is connected to R167, U5 Pin A14 and P9 Pin 25


I am not sure exactly which signal you are chasing.

A good reference for which signals are routed to which pins under which modes is Molloy’s Header Charts:

Download the P8 and P9 header charts.

They also give you a good idea of potential conflicts.

I find reading these easier than chasing things on the schematic.

— Graham

Thanks, John!