We designed a custom made board based on NUCLEO-U575ZI-Q schematic. Specifically, we copied the USB-C connection part including the TCPP01-M12. The design is BUS powered. The devices are only recognized if connected via USB-A to USB-C adapters or if the CC1/CC2 pins are shortly shorted to GND while plugged in an USB-C connector, i.e. forcing an re enumeration. In the Nucleo schematic capactors (C62 & C 63)are placed at CC1/CC2 between MCU and the TCPP01-M12:
The TCPP01-M12 datasheets places them on the CC1c/CC2c pin, i.e. between USB connector and the TCPP01-M12:
Furthermore it specifies:
After rewiring the caps the boards are recognized more reliable but still some fail. So questions are:
-is the TCPP01-M12 functionallity influenced by the placement of the capacitors at CCxc vs CCx?
-what are potential reasons to fail negotiations while plugging in (i.e. only voltages at CCxc pins and VBUS is low - disconnected by host) but succeeding if CCxc is shorted shortly?
P.S.: we are still investigating the influence wether the DB/ connected to the MCU might have an influence.
