GPIO pins used

v1.x HAT

• GPIO2 — I2C SDA
• GPIO3 — I2C SCL
• GPIO4 — PCB button on HAT 1.1 and 1.2
• GPIO12 — PWM channel 4
• GPIO13 — PWM channel 2
• GPIO16 — PWM channel 3
• GPIO17 — PWM channel 1
• GPIO18 — PWM channel 5, used for heating
• GPIO21 — hall sensor on HAT 1.1 and 1.2
• GPIO23 — PCB LED
• GPIO24 — PCB button on HAT 1.0, SWD on HAT 1.1 and 1.2
• GPIO25 — hall sensor on HAT 1.0, SWD on HAT 1.1 and 1.2