# SPDX-FileCopyrightText: 2016 Scott Shawcroft for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# pylint: disable=too-few-public-methods
"""
`adafruit_register.i2c_bit`
====================================================
Single bit registers
* Author(s): Scott Shawcroft
"""
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Register.git"
class RWBit:
"""
Single bit register that is readable and writeable.
Values are `bool`
:param int register_address: The register address to read the bit from
:param type bit: The bit index within the byte at ``register_address``
:param int register_width: The number of bytes in the register. Defaults to 1.
:param bool lsb_first: Is the first byte we read from I2C the LSB? Defaults to true
"""
def __init__(self, register_address, bit, register_width=1, lsb_first=True):
self.bit_mask = 1 << (bit % 8) # the bitmask *within* the byte!
self.buffer = bytearray(1 + register_width)
self.buffer[0] = register_address
if lsb_first:
self.byte = bit // 8 + 1 # the byte number within the buffer
else:
self.byte = register_width - (bit // 8) # the byte number within the buffer
def __get__(self, obj, objtype=None):
with obj.i2c_device as i2c:
i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
return bool(self.buffer[self.byte] & self.bit_mask)
def __set__(self, obj, value):
with obj.i2c_device as i2c:
i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
if value:
self.buffer[self.byte] |= self.bit_mask
else:
self.buffer[self.byte] &= ~self.bit_mask
i2c.write(self.buffer)
class ROBit(RWBit):
"""Single bit register that is read only. Subclass of `RWBit`.
Values are `bool`
:param int register_address: The register address to read the bit from
:param type bit: The bit index within the byte at ``register_address``
:param int register_width: The number of bytes in the register. Defaults to 1.
"""
def __set__(self, obj, value):
raise AttributeError()