Test points
It can be quite useful to add test points for all data lines (MISO, MOSI, D+, D- etc) to check out what data the mcu and the different interfaces generates. But prioritize to fit all components firstly.
It can be quite useful to add test points for all data lines (MISO, MOSI, D+, D- etc) to check out what data the mcu and the different interfaces generates. But prioritize to fit all components firstly.