Hi,
Does anyone able to share how to write a callback event on falling edge on an Input GPIO. I can't find any example on how the lib handle event instead of using pulling method to find falling event.
Please helps.
Hello, you can refer to the following sample.
#!/usr/bin/env python
#
import gpiod
import time
# Define the chip and lines
chipname = "gpiochip0" #Please use gpiochip0 if using Raspberry pi 4/3 hardware
# chipname = "gpiochip4" #Please use gpiochip4 if using Raspberry pi 5 hardware
line_offset = 6
# Open the GPIO chip
chip = gpiod.Chip(chipname)
# Get the input line
line = chip.get_line(line_offset)
line.request(consumer="my_program", type=gpiod.LINE_REQ_EV_BOTH_EDGES)
def print_event(event):
if event.type == gpiod.LineEvent.RISING_EDGE:
print("---AC Power Loss OR Power Adapter Failure---")
print("Shutdown in 5 seconds")
time.sleep(5)
elif event.type == gpiod.LineEvent.FALLING_EDGE:
print("---AC Power OK, Power Adapter OK---")
try:
# Wait for events indefinitely
while True:
event = line.event_wait()
if event:
event = line.event_read()
print_event(event)
except KeyboardInterrupt:
print("Exiting...")
finally:
chip.close()
