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# SPDX-FileCopyrightText: 2016 Scott Shawcroft for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# pylint: disable=too-few-public-methods
"""
`adafruit_register.i2c_bcd_datetime`
====================================================
Binary Coded Decimal date and time register
* Author(s): Scott Shawcroft
"""
__version__ = "0.0.0+auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Register.git"
import time
try:
from typing import Optional, Type
from typing_extensions import Literal
from circuitpython_typing.device_drivers import I2CDeviceDriver
except ImportError:
pass
def _bcd2bin(value: int) -> int:
"""Convert binary coded decimal to Binary
:param value: the BCD value to convert to binary (required, no default)
"""
return value - 6 * (value >> 4)
def _bin2bcd(value: int) -> int:
"""Convert a binary value to binary coded decimal.
:param value: the binary value to convert to BCD. (required, no default)
"""
return value + 6 * (value // 10)
class BCDDateTimeRegister:
"""
Date and time register using binary coded decimal structure.
The byte order of the register must* be: second, minute, hour, weekday, day (1-31), month, year
(in years after 2000).
* Setting weekday_first=False will flip the weekday/day order so that day comes first.
Values are `time.struct_time`
:param int register_address: The register address to start the read
:param bool weekday_first: True if weekday is in a lower register than the day of the month
(1-31)
:param int weekday_start: 0 or 1 depending on the RTC's representation of the first day of the
week
"""
def __init__(
self,
register_address: int,
weekday_first: bool = True,
weekday_start: Literal[0, 1] = 1,
) -> None:
self.buffer = bytearray(8)
self.buffer[0] = register_address
if weekday_first:
self.weekday_offset = 0
else:
self.weekday_offset = 1
self.weekday_start = weekday_start
# Masking value list n/a sec min hr day wkday mon year
self.mask_datetime = b"\xFF\x7F\x7F\x3F\x3F\x07\x1F\xFF"
def __get__(
self,
obj: Optional[I2CDeviceDriver],
objtype: Optional[Type[I2CDeviceDriver]] = None,
) -> time.struct_time:
# Read and return the date and time.
with obj.i2c_device as i2c:
i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
return time.struct_time(
(
_bcd2bin(self.buffer[7] & self.mask_datetime[7]) + 2000,
_bcd2bin(self.buffer[6] & self.mask_datetime[6]),
_bcd2bin(self.buffer[5 - self.weekday_offset] & self.mask_datetime[4]),
_bcd2bin(self.buffer[3] & self.mask_datetime[3]),
_bcd2bin(self.buffer[2] & self.mask_datetime[2]),
_bcd2bin(self.buffer[1] & self.mask_datetime[1]),
_bcd2bin(
(self.buffer[4 + self.weekday_offset] & self.mask_datetime[5])
- self.weekday_start
),
-1,
-1,
)
)
def __set__(self, obj: I2CDeviceDriver, value: time.struct_time) -> None:
self.buffer[1] = _bin2bcd(value.tm_sec) & 0x7F # format conversions
self.buffer[2] = _bin2bcd(value.tm_min)
self.buffer[3] = _bin2bcd(value.tm_hour)
self.buffer[4 + self.weekday_offset] = _bin2bcd(
value.tm_wday + self.weekday_start
)
self.buffer[5 - self.weekday_offset] = _bin2bcd(value.tm_mday)
self.buffer[6] = _bin2bcd(value.tm_mon)
self.buffer[7] = _bin2bcd(value.tm_year - 2000)
with obj.i2c_device:
obj.i2c_device.write(self.buffer)
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