So the RJ45 pinout is as below (here):
1 - 5V
2 - GND
3 - SPI2_CLK
4 - SPI2_MISO
5 - SPI2_MOSI
6 - SPI2_NSS
7 - I2C2_SCL
8 - I2C2_SDA
In terms of accessing the signals, something like this is probably the easiest, unless you'd like to make a custom harness:
And for accessing SPI, see here:
And for I2C, see here:
Both of those examples are by default setup for the ports mapped above (SPI2 and I2C2).
And the OpenMV IDE has examples built-in for these:
Overall though, it's likely best to move OpenMV questions to the OpenMV forum (here) as we simply re-laid-out the H7 design because Kwabena thought it would be useful to his customers. It was more-or-less a weekend project for us and we're not experts on the system (whereas we are on megaAI and DepthAI).
Anyway, happy to answer questions, but just as a heads up it will probably be out of my depth WRT the OpenMV systems quickly, as we actually haven't used SPI/I2C on OpenMV, we just implemented the hardware to be compatible w/ the existing OpenMV implementations.