I would like to pass through some signals (buttons, LEDs, etc.), but confess that I’m not understanding what I’m seeing on the schematic. Things like MISO, MOSI, SCL, SDA, and SCK all look like they are used by the shield, so would that leave IO7 - IO4 available? Have I an reasonable understanding? Yes, I could (and will) also try it to see if it works, but I’d appreciate some pointers on interpreting the schematic.
Thanks so much for your response. May I verify that any pin that isn’t explicitly routed to an IC on the shield is being passed through? Here we see digital pins 0, 1, 8 don’t have any connections and the same is true for analog pins 2 - 5 (along with ground pins). Therefore, those pins are available to pass directly through – yes?
Took me a while before I could come back to this. All of the pins have continuity between the header and pins, so it looks like the board file is the way to go.