4. GPIO Pins¶
Use machine.Pin to control I/O pins.
For Zephyr, pins are initialized using a tuple of port and pin number (\"GPIO_x\", pin#)
for the id
value. For example to initialize a pin for the red LED on a FRDM-k64 board:
LED = Pin(("GPIO_1", 22), Pin.OUT)
Reference your board's datasheet or Zephyr documentation for pin numbers, see below for more examples.
Board | Pin | Format |
---|---|---|
frdm_k64f | Red LED = PTB22 | ("GPIO_1", 22) |
96b_carbon | LED1 = PD2 | ("GPIOD", 2) |
mimxrt685_evk_cm33 | Green LED = PIO0_14 | ("GPIO0", 14) |
4.1. Interrupts¶
The Zephyr port also supports interrupt handling for Pins using machine.Pin.irq()
.
To respond to Pin change IRQs run:
from machine import Pin
SW2 = Pin(("GPIO_2", 6), Pin.IN) # create Pin object for switch 2
SW3 = Pin(("GPIO_0", 4), Pin.IN) # create Pin object for switch 3
SW2.irq(lambda t: print("SW2 changed")) # print message when SW2 state is changed (triggers change IRQ)
SW3.irq(lambda t: print("SW3 changed")) # print message when SW3 state is changed (triggers change IRQ)
while True: # wait
pass