I'm building a project that needs to read 32 buttons.
I've modified demo_interruptsthreading.py to create two busses and threads to scan them but it's not working.
Whichever bus I set as bus1 works as expected but bus2 doesn't trigger. Any help would be much appreciated.
Here's the code:
#!/usr/bin/env python
"""
================================================
ABElectronics IO Pi | - IO Interrupts Demo
Requires python smbus to be installed
For Python 2 install with: sudo apt-get install python-smbus
For Python 3 install with: sudo apt-get install python3-smbus
run with: python demo_iointerruptsthreading.py
================================================
This example shows how to use the interrupt methods with threading
on the IO port.
The interrupts will be enabled and set so that pin 1 will trigger INT A and B.
Internal pull-up resistors will be used so grounding
one of the pins will trigger the interrupt
using the read_interrupt_capture or reset_interrupts methods
will reset the interrupts.
"""
from __future__ import absolute_import, division, print_function, \
unicode_literals
import time
import threading
try:
from IOPi import IOPi
except ImportError:
print("Failed to import IOPi from python system path")
print("Importing from parent folder instead")
try:
import sys
sys.path.append('..')
from IOPi import IOPi
except ImportError:
raise ImportError(
"Failed to import library from parent folder")
def callback_function(bus):
"""
Function we want to call from the background_thread function
This function will be called when an interrupt is triggered from
a state change on pin 1
"""
print("interrupt triggered")
if bus.read_pin(1) == 0:
print("pin 1 was set low")
else:
print("pin 1 was set high")
def background_thread1(bus):
"""
Function we want to run in parallel with the main program loop
"""
while 1:
# get the interrupt status for INTA
inta = bus.read_interrupt_status(0)
intb = bus.read_interrupt_status(1)
# reset the interrupts
bus.reset_interrupts()
# check the value of intA to see if an interrupt has occurred
if inta != 0 or intb != 0:
print("Bus1", bus.read_pin(1), bus.read_pin(2), bus.read_pin(3), bus.read_pin(4), bus.read_pin(5), bus.read_pin(6), bus.read_pin(7), bus.read_pin(8), bus.read_pin(9), bus.read_pin(10), bus.read_pin(11), bus.read_pin(12), bus.read_pin(13), bus.read_pin(14), bus.read_pin(15), bus.read_pin(16))
callback_function(bus)
# sleep this thread for 0.5 seconds
time.sleep(0.01)
def background_thread2(bus):
"""
Function we want to run in parallel with the main program loop
"""
while 1:
# get the interrupt status for INTA
inta = bus.read_interrupt_status(0)
intb = bus.read_interrupt_status(1)
# reset the interrupts
bus.reset_interrupts()
# check the value of intA to see if an interrupt has occurred
if inta != 0 or intb != 0:
print("Bus2",bus.read_pin(1), bus.read_pin(2), bus.read_pin(3), bus.read_pin(4), bus.read_pin(5), bus.read_pin(6), bus.read_pin(7), bus.read_pin(8), bus.read_pin(9), bus.read_pin(10), bus.read_pin(11), bus.read_pin(12), bus.read_pin(13), bus.read_pin(14), bus.read_pin(15), bus.read_pin(16))
callback_function(bus)
# sleep this thread for 0.5 seconds
time.sleep(0.01)
def create_bus(address):
# Create an instance of the IOPi class with an I2C address supplied
iobus = IOPi(address)
# Set all pins on the IO bus to be inputs with internal pull-ups enabled.
iobus.set_port_pullups(0, 0xFF)
iobus.set_port_pullups(1, 0xFF)
iobus.set_port_direction(0, 0xFF)
iobus.set_port_direction(1, 0xFF)
# invert the ports so pulling a pin to ground will show as 1 instead of 0
iobus.invert_port(0, 0xFF)
iobus.invert_port(1, 0xFF)
# Set the interrupt polarity to be active high and mirroring enabled, so
# pin 1 will trigger both INT A and INT B when a pin is grounded
iobus.set_interrupt_polarity(1)
iobus.mirror_interrupts(1)
# Set the interrupts default value to 0
iobus.set_interrupt_defaults(0, 0x00)
iobus.set_interrupt_defaults(1, 0x00)
# Set the interrupt type to be 1 for ports A and B so an interrupt is
# fired when a state change occurs
iobus.set_interrupt_type(0, 0x00)
iobus.set_interrupt_type(1, 0x00)
# Enable interrupts for pin 1
iobus.set_interrupt_on_port(0, 0xFF)
iobus.set_interrupt_on_port(1, 0xFF)
return(iobus)
def main():
'''
Main program function
'''
bus1 = create_bus(0x20)
bus2 = create_bus(0x21)
timer1 = threading.Thread(target=background_thread1(bus1))
timer1.daemon = True # set thread to daemon ('ok' won't be printed)
timer1.start()
timer2 = threading.Thread(target=background_thread2(bus2))
timer2.daemon = True # set thread to daemon ('ok' won't be printed)
timer2.start()
while 1:
"""
Do something in the main program loop while the interrupt checking
is carried out in the background
"""
# wait 1 seconds
time.sleep(1)
if __name__ == "__main__":
main()
