USB serial communication with Watchy did not work and I saw the circuit.
In the Rev2.0 schematic, CP2104 is replaced with "CP2102", but it looks like CP2102N because it has 24 pins (CP2102 is QFN28, isn't it?).
Also, Silabs documentation AN976 tells you to use a resistor divider when replacing CP2104 with CP2102N and should be fixed.
USB serial communication with Watchy did not work and I saw the circuit. In the Rev2.0 schematic, CP2104 is replaced with "CP2102", but it looks like CP2102N because it has 24 pins (CP2102 is QFN28, isn't it?). Also, Silabs documentation AN976 tells you to use a resistor divider when replacing CP2104 with CP2102N and should be fixed.