1  # SPDX-FileCopyrightText: 2017 Tony DiCola for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  # Simple demo of reading and writing the digital I/O of the MCP2300xx as if
 6  # they were native CircuitPython digital inputs/outputs.
 7  # Author: Tony DiCola
 8  import time
 9  
10  import board
11  import busio
12  import digitalio
13  
14  from adafruit_mcp230xx.mcp23008 import MCP23008
15  
16  # from adafruit_mcp230xx.mcp23017 import MCP23017
17  
18  
19  # Initialize the I2C bus:
20  i2c = busio.I2C(board.SCL, board.SDA)
21  
22  # Create an instance of either the MCP23008 or MCP23017 class depending on
23  # which chip you're using:
24  mcp = MCP23008(i2c)  # MCP23008
25  # mcp = MCP23017(i2c)  # MCP23017
26  
27  # Optionally change the address of the device if you set any of the A0, A1, A2
28  # pins.  Specify the new address with a keyword parameter:
29  # mcp = MCP23017(i2c, address=0x21)  # MCP23017 w/ A0 set
30  
31  # Now call the get_pin function to get an instance of a pin on the chip.
32  # This instance will act just like a digitalio.DigitalInOut class instance
33  # and has all the same properties and methods (except you can't set pull-down
34  # resistors, only pull-up!).  For the MCP23008 you specify a pin number from 0
35  # to 7 for the GP0...GP7 pins.  For the MCP23017 you specify a pin number from
36  # 0 to 15 for the GPIOA0...GPIOA7, GPIOB0...GPIOB7 pins (i.e. pin 12 is GPIOB4).
37  pin0 = mcp.get_pin(0)
38  pin1 = mcp.get_pin(1)
39  
40  # Setup pin0 as an output that's at a high logic level.
41  pin0.switch_to_output(value=True)
42  
43  # Setup pin1 as an input with a pull-up resistor enabled.  Notice you can also
44  # use properties to change this state.
45  pin1.direction = digitalio.Direction.INPUT
46  pin1.pull = digitalio.Pull.UP
47  
48  # Now loop blinking the pin 0 output and reading the state of pin 1 input.
49  while True:
50      # Blink pin 0 on and then off.
51      pin0.value = True
52      time.sleep(0.5)
53      pin0.value = False
54      time.sleep(0.5)
55      # Read pin 1 and print its state.
56      print("Pin 1 is at a high level: {0}".format(pin1.value))