For 1-Wire (iButton) devices this is the wire.  It has built-in 1K pull-up resistor to 5 volts.

Generic GPIO uses PC0.

CHECK: "PB14/TIM1.2N/I2C3.SDA-Pullup"

Devices:
- iButton[1Wire] (center of button)
- DS18B20[1Wire] (yellow wire)