gpio.py

import smbus

# MCP23008 Register Addresses
IODIR           = 0x00   # GPIO direction register
#GPPU           = 0x06    # Pull-up resistor register
GPIOREG         = 0x09    # GPIO register
OLAT            = 0x0A    # Output latch register

class MCP23008:
	def __init__(self, bus, address):
		self.bus = bus
		self.address = address
		self.init_device()

	def init_device(self):
		try:
			# Initialize all GPIO pins as outputs and set to LOW
			self.bus.write_byte_data(self.address, IODIR, 0x00)  # All pins as outputs
			self.bus.write_byte_data(self.address, OLAT, 0x00)   # All pins LOW
		except:
			print("Warning! MCP23008 unavailable at I2C address " + str(self.address))

	def set_pin(self, pin, value):
		try:
			# Set the state of a specific pin (0 or 1)
			current_value = self.bus.read_byte_data(self.address, OLAT)
			if value:
				current_value |= (1 << pin)   # Set bit
			else:
				current_value &= ~(1 << pin)  # Clear bit
			self.bus.write_byte_data(self.address, OLAT, current_value)
		except:
			pass

	def get_pin(self, pin):
		# Get the state of a specific pin
		return (self.bus.read_byte_data(self.address, GPIOREG) >> pin) & 0x01

class GPIO:
	def __init__(self):
		try:
			bus = smbus.SMBus(1)  # Initialize I2C bus

			# I2C addresses of the MCP23008 devices
			i2c_addresses = [0x20, 0x21, 0x23]

			# Initialize MCP23008 devices and store them in a list
			self.mcp_devices = [MCP23008(bus, addr) for addr in i2c_addresses]
		except:
			print("MCP23008 GPIO expanders not detected!")

	# Find MCP23008 device by I2C address
	def set_pin_from_address(self, i2c_address, pin, value):
		if hasattr(self, "mcp_devices") and self.mcp_devices is not None:
			for mcp in self.mcp_devices:
				if mcp.address == i2c_address:
					mcp.set_pin(pin,value)
					
		return None