# The MIT License (MIT)
#
# Copyright (c) 2017 Carter Nelson for adafruit
#
# 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.
# pylint: disable=C0103
"""
`adafruit_ds2413`
====================================================
CircuitPython driver for the DS2413 one wire 2 channel GPIO breakout.
* Author(s): Carter Nelson
"""
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_DS2413.git"
from adafruit_onewire.device import OneWireDevice
from micropython import const
_DS2413_ACCESS_READ = b'\xF5'
_DS2413_ACCESS_WRITE = b'\x5A'
_DS2413_ACK_SUCCESS = b'\xAA'
_DS2413_ACK_ERROR = b'\xFF'
INPUT = const(0)
OUTPUT = const(1)
[docs]class DS2413Pin():
"""Class which provides interface to single DS2413 GPIO pin."""
def __init__(self, number, host, direction=OUTPUT):
if number not in (0, 1):
raise ValueError("Incorrect pin number.")
self._number = number
self._host = host
self._mask = 1 << (number * 2)
self._direction = None # create it, and then...
self.direction = direction # set it through setter
@property
def direction(self):
"""The direction of the pin, either INPUT or OUTPUT."""
return self._direction
@direction.setter
def direction(self, direction):
if direction not in (INPUT, OUTPUT):
raise ValueError("Incorrect direction setting.")
self._direction = OUTPUT
self.value = False
self._direction = direction
@property
def value(self):
"""The pin state if configured as INPUT. The output latch state
if configured as OUTPUT. True is HIGH/ON, False is LOW/OFF."""
# return Pin State if configured for INPUT
# return Latch State if configured for OUTPUT
# NOTE: logic is re-inverted to make it more normally
return not self._host.pio_state & (self._mask << self._direction)
@value.setter
def value(self, state):
# This only makes sense if the pin is configured for OUTPUT.
if self._direction == INPUT:
raise RuntimeError("Can't set value when pin is set to input.")
# We jump through some hoops in order to only set/clear the bit
# for the channel associated with this pin object.
current = self._host.pio_state
# PIOB Output Latch PIOA Output Latch
new = (current >> 2 & 0x02) | (current >> 1 & 0x01)
# To switch the output transistor on, the corresponding bit value is 0.
# To switch the output transistor off (non-conducting) the bit must be 1.
if state:
# clear it (transistor = ON)
new &= ~(1 << self._number)
else:
# set it (transistor = OFF)
new |= 1 << self._number
self._host.pio_state = new
[docs]class DS2413():
"""Class which provides interface to DS2413 GPIO breakout."""
def __init__(self, bus, address):
if address.family_code == 0x3A:
self._address = address
self._device = OneWireDevice(bus, address)
self._buf = bytearray(3)
self._IOA = None
self._IOB = None
else:
raise RuntimeError('Incorrect family code in device address.')
@property
def IOA(self):
"""The pin object for channel A."""
if self._IOA is None:
self._IOA = DS2413Pin(0, self)
return self._IOA
@property
def IOB(self):
"""The pin object for channel B."""
if self._IOB is None:
self._IOB = DS2413Pin(1, self)
return self._IOB
@property
def pio_state(self):
"""The state of both PIO channels."""
return self._read_status()
@pio_state.setter
def pio_state(self, value):
return self._write_latches(value)
def _read_status(self):
with self._device as dev:
dev.write(_DS2413_ACCESS_READ)
dev.readinto(self._buf, end=1)
return self._buf[0]
def _write_latches(self, value):
# top six bits must be 1
value |= 0xFC
self._buf[0] = value
self._buf[1] = ~value & 0xFF
with self._device as dev:
dev.write(_DS2413_ACCESS_WRITE)
dev.write(self._buf, end=2)
dev.readinto(self._buf, end=1)
if not self._buf[0] == ord(_DS2413_ACK_SUCCESS):
raise RuntimeError('ACK failure.')