# SPDX-FileCopyrightText: 2017 Carter Nelson for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# 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 micropython import const
from adafruit_onewire.device import OneWireDevice
try:
import typing # pylint: disable=unused-import
from typing_extensions import Literal
from adafruit_onewire.bus import OneWireBus # pylint: disable=ungrouped-imports
except ImportError:
pass
_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: Literal[0, 1], host, direction: Literal[0, 1] = OUTPUT
) -> None:
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) -> Literal[0, 1]:
"""The direction of the pin, either INPUT or OUTPUT."""
return self._direction
@direction.setter
def direction(self, direction: Literal[0, 1]) -> None:
if direction not in (INPUT, OUTPUT):
raise ValueError("Incorrect direction setting.")
self._direction = OUTPUT
self.value = False
self._direction = direction
@property
def value(self) -> bool:
"""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: bool) -> None:
# 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: OneWireBus, address: int) -> None:
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) -> DS2413Pin:
"""The pin object for channel A."""
if self._IOA is None:
self._IOA = DS2413Pin(0, self)
return self._IOA
@property
def IOB(self) -> DS2413Pin:
"""The pin object for channel B."""
if self._IOB is None:
self._IOB = DS2413Pin(1, self)
return self._IOB
@property
def pio_state(self) -> int:
"""The state of both PIO channels."""
return self._read_status()
@pio_state.setter
def pio_state(self, value: int) -> None:
return self._write_latches(value)
def _read_status(self) -> int:
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: int) -> None:
# 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.")