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# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
import math
import Adafruit_GPIO as GPIO
import Adafruit_GPIO.I2C as I2C
class MCP230xxBase(GPIO.BaseGPIO):
"""Base class to represent an MCP230xx series GPIO extender. Is compatible
with the Adafruit_GPIO BaseGPIO class so it can be used as a custom GPIO
class for interacting with device.
"""
def __init__(self, address, i2c=None, **kwargs):
"""Initialize MCP230xx at specified I2C address and bus number. If bus
is not specified it will default to the appropriate platform detected bus.
"""
# Create I2C device.
if i2c is None:
import Adafruit_GPIO.I2C as I2C
i2c = I2C
self._device = i2c.get_i2c_device(address, **kwargs)
# Assume starting in ICON.BANK = 0 mode (sequential access).
# Compute how many bytes are needed to store count of GPIO.
self.gpio_bytes = int(math.ceil(self.NUM_GPIO/8.0))
# Buffer register values so they can be changed without reading.
self.iodir = [0xFF]*self.gpio_bytes # Default direction to all inputs.
self.gppu = [0x00]*self.gpio_bytes # Default to pullups disabled.
self.gpio = [0x00]*self.gpio_bytes
# Write current direction and pullup buffer state.
self.write_iodir()
self.write_gppu()
def setup(self, pin, value):
"""Set the input or output mode for a specified pin. Mode should be
either GPIO.OUT or GPIO.IN.
"""
self._validate_pin(pin)
# Set bit to 1 for input or 0 for output.
if value == GPIO.IN:
self.iodir[int(pin/8)] |= 1 << (int(pin%8))
elif value == GPIO.OUT:
self.iodir[int(pin/8)] &= ~(1 << (int(pin%8)))
else:
raise ValueError('Unexpected value. Must be GPIO.IN or GPIO.OUT.')
self.write_iodir()
def output(self, pin, value):
"""Set the specified pin the provided high/low value. Value should be
either GPIO.HIGH/GPIO.LOW or a boolean (True = HIGH).
"""
self.output_pins({pin: value})
def output_pins(self, pins):
"""Set multiple pins high or low at once. Pins should be a dict of pin
name to pin value (HIGH/True for 1, LOW/False for 0). All provided pins
will be set to the given values.
"""
[self._validate_pin(pin) for pin in pins.keys()]
# Set each changed pin's bit.
for pin, value in iter(pins.items()):
if value:
self.gpio[int(pin/8)] |= 1 << (int(pin%8))
else:
self.gpio[int(pin/8)] &= ~(1 << (int(pin%8)))
# Write GPIO state.
self.write_gpio()
def input(self, pin):
"""Read the specified pin and return GPIO.HIGH/True if the pin is pulled
high, or GPIO.LOW/False if pulled low.
"""
return self.input_pins([pin])[0]
def input_pins(self, pins):
"""Read multiple pins specified in the given list and return list of pin values
GPIO.HIGH/True if the pin is pulled high, or GPIO.LOW/False if pulled low.
"""
[self._validate_pin(pin) for pin in pins]
# Get GPIO state.
self.gpio = self._device.readList(self.GPIO, self.gpio_bytes)
# Return True if pin's bit is set.
return [(self.gpio[int(pin/8)] & 1 << (int(pin%8))) > 0 for pin in pins]
def pullup(self, pin, enabled):
"""Turn on the pull-up resistor for the specified pin if enabled is True,
otherwise turn off the pull-up resistor.
"""
self._validate_pin(pin)
if enabled:
self.gppu[int(pin/8)] |= 1 << (int(pin%8))
else:
self.gppu[int(pin/8)] &= ~(1 << (int(pin%8)))
self.write_gppu()
def write_gpio(self, gpio=None):
"""Write the specified byte value to the GPIO registor. If no value
specified the current buffered value will be written.
"""
if gpio is not None:
self.gpio = gpio
self._device.writeList(self.GPIO, self.gpio)
def write_iodir(self, iodir=None):
"""Write the specified byte value to the IODIR registor. If no value
specified the current buffered value will be written.
"""
if iodir is not None:
self.iodir = iodir
self._device.writeList(self.IODIR, self.iodir)
def write_gppu(self, gppu=None):
"""Write the specified byte value to the GPPU registor. If no value
specified the current buffered value will be written.
"""
if gppu is not None:
self.gppu = gppu
self._device.writeList(self.GPPU, self.gppu)
class MCP23017(MCP230xxBase):
"""MCP23017-based GPIO class with 16 GPIO pins."""
# Define number of pins and registor addresses.
NUM_GPIO = 16
IODIR = 0x00
GPIO = 0x12
GPPU = 0x0C
def __init__(self, address=0x20, **kwargs):
super(MCP23017, self).__init__(address, **kwargs)
class MCP23008(MCP230xxBase):
"""MCP23008-based GPIO class with 8 GPIO pins."""
# Define number of pins and registor addresses.
NUM_GPIO = 8
IODIR = 0x00
GPIO = 0x09
GPPU = 0x06
def __init__(self, address=0x20, **kwargs):
super(MCP23008, self).__init__(address, **kwargs)
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