1  # SPDX-FileCopyrightText: 2017 Tony DiCola for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  from time import sleep
 6  
 7  import board
 8  import busio
 9  from digitalio import Direction, Pull
10  from RPi import GPIO
11  from adafruit_mcp230xx.mcp23017 import MCP23017
12  
13  # Initialize the I2C bus:
14  i2c = busio.I2C(board.SCL, board.SDA)
15  
16  # Initialize the MCP23017 chip on the bonnet
17  mcp = MCP23017(i2c)
18  
19  # Optionally change the address of the device if you set any of the A0, A1, A2
20  # pins.  Specify the new address with a keyword parameter:
21  # mcp = MCP23017(i2c, address=0x21)  # MCP23017 w/ A0 set
22  
23  # Make a list of all the pins (a.k.a 0-16)
24  pins = []
25  for pin in range(0, 16):
26      pins.append(mcp.get_pin(pin))
27  
28  # Set all the pins to input
29  for pin in pins:
30      pin.direction = Direction.INPUT
31      pin.pull = Pull.UP
32  
33  # Set up to check all the port B pins (pins 8-15) w/interrupts!
34  mcp.interrupt_enable = 0xFFFF  # Enable Interrupts in all pins
35  # If intcon is set to 0's we will get interrupts on
36  # both button presses and button releases
37  mcp.interrupt_configuration = 0x0000  # interrupt on any change
38  mcp.io_control = 0x44  # Interrupt as open drain and mirrored
39  mcp.clear_ints()  # Interrupts need to be cleared initially
40  
41  # Or, we can ask to be notified CONTINUOUSLY if a pin goes LOW (button press)
42  # we won't get an IRQ pulse when the pin is HIGH!
43  # mcp.interrupt_configuration = 0xFFFF         # notify pin value
44  # mcp.default_value = 0xFFFF         # default value is 'high' so notify whenever 'low'
45  
46  
47  def print_interrupt(port):
48      """Callback function to be called when an Interrupt occurs."""
49      for pin_flag in mcp.int_flag:
50          print("Interrupt connected to Pin: {}".format(port))
51          print("Pin number: {} changed to: {}".format(pin_flag, pins[pin_flag].value))
52      mcp.clear_ints()
53  
54  
55  # connect either interrupt pin to the Raspberry pi's pin 17.
56  # They were previously configured as mirrored.
57  GPIO.setmode(GPIO.BCM)
58  interrupt = 17
59  GPIO.setup(interrupt, GPIO.IN, GPIO.PUD_UP)  # Set up Pi's pin as input, pull up
60  
61  # The add_event_detect fuction will call our print_interrupt callback function
62  # every time an interrupt gets triggered.
63  GPIO.add_event_detect(interrupt, GPIO.FALLING, callback=print_interrupt, bouncetime=10)
64  
65  # The following lines are so the program runs for at least 60 seconds,
66  # during that time it will detect any pin interrupt and print out the pin number
67  # that changed state and its current state.
68  # The program can be terminated using Ctrl+C. It doesn't matter how it
69  # terminates it will always run GPIO.cleanup().
70  try:
71      print("When button is pressed you'll see a message")
72      sleep(60)  # You could run your main while loop here.
73      print("Time's up. Finished!")
74  finally:
75      GPIO.cleanup()