# SPDX-FileCopyrightText: 2016 Scott Shawcroft for Adafruit Industries
#
# SPDX-License-Identifier: MIT
# pylint: disable=too-few-public-methods
"""
`adafruit_register.i2c_bcd_alarm`
====================================================
Binary Coded Decimal alarm 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, Tuple
from typing_extensions import Literal
from circuitpython_typing.device_drivers import I2CDeviceDriver
FREQUENCY_T = Literal[
"monthly", "weekly", "daily", "hourly", "secondly", "minutely"
]
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)
ALARM_COMPONENT_DISABLED = 0x80
FREQUENCY = ["secondly", "minutely", "hourly", "daily", "weekly", "monthly"]
[docs]
class BCDAlarmTimeRegister:
"""
Alarm date and time register using binary coded decimal structure.
The byte order of the registers must* be: [second], minute, hour, day,
weekday. Each byte must also have a high enable bit where 1 is disabled and
0 is enabled.
* If weekday_shared is True, then weekday and day share a register.
* If has_seconds is True, then there is a seconds register.
Values are a tuple of (`time.struct_time`, `str`) where the struct represents
a date and time that would alarm. The string is the frequency:
* "secondly", once a second (only if alarm has_seconds)
* "minutely", once a minute when seconds match (if alarm doesn't seconds then when seconds = 0)
* "hourly", once an hour when ``tm_min`` and ``tm_sec`` match
* "daily", once a day when ``tm_hour``, ``tm_min`` and ``tm_sec`` match
* "weekly", once a week when ``tm_wday``, ``tm_hour``, ``tm_min``, ``tm_sec`` match
* "monthly", once a month when ``tm_mday``, ``tm_hour``, ``tm_min``, ``tm_sec`` match
:param int register_address: The register address to start the read
:param bool has_seconds: True if the alarm can happen minutely.
:param bool weekday_shared: True if weekday and day share the same register
:param int weekday_start: 0 or 1 depending on the RTC's representation of the first day of the
week (Monday)
"""
# Defaults are based on alarm1 of the DS3231.
def __init__(
self,
register_address: int,
has_seconds: bool = True,
weekday_shared: bool = True,
weekday_start: Literal[0, 1] = 1,
) -> None:
buffer_size = 5
if weekday_shared:
buffer_size -= 1
if has_seconds:
buffer_size += 1
self.has_seconds = has_seconds
self.buffer = bytearray(buffer_size)
self.buffer[0] = register_address
self.weekday_shared = weekday_shared
self.weekday_start = weekday_start
def __get__(
self,
obj: Optional[I2CDeviceDriver],
objtype: Optional[Type[I2CDeviceDriver]] = None,
) -> Tuple[time.struct_time, FREQUENCY_T]:
# Read the alarm register.
with obj.i2c_device as i2c:
i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
frequency = None
i = 1
seconds = 0
if self.has_seconds:
if (self.buffer[1] & 0x80) != 0:
frequency = "secondly"
else:
frequency = "minutely"
seconds = _bcd2bin(self.buffer[1] & 0x7F)
i = 2
minute = 0
if (self.buffer[i] & 0x80) == 0:
frequency = "hourly"
minute = _bcd2bin(self.buffer[i] & 0x7F)
hour = 0
if (self.buffer[i + 1] & 0x80) == 0:
frequency = "daily"
hour = _bcd2bin(self.buffer[i + 1] & 0x7F)
mday = None
wday = None
if (self.buffer[i + 2] & 0x80) == 0:
# day of the month
if not self.weekday_shared or (self.buffer[i + 2] & 0x40) == 0:
frequency = "monthly"
mday = _bcd2bin(self.buffer[i + 2] & 0x3F)
else: # weekday
frequency = "weekly"
wday = _bcd2bin(self.buffer[i + 2] & 0x3F) - self.weekday_start
# weekday
if not self.weekday_shared and (self.buffer[i + 3] & 0x80) == 0:
frequency = "monthly"
mday = _bcd2bin(self.buffer[i + 3] & 0x7F)
if mday is not None:
wday = (mday - 2) % 7
elif wday is not None:
mday = wday + 2
else:
# Jan 1, 2017 was a Sunday (6)
wday = 6
mday = 1
return (
time.struct_time((2017, 1, mday, hour, minute, seconds, wday, mday, -1)),
frequency,
)
def __set__(
self, obj: I2CDeviceDriver, value: Tuple[time.struct_time, FREQUENCY_T]
) -> None:
if len(value) != 2:
raise ValueError("Value must be sequence of length two")
# Turn all components off by default.
for i in range(len(self.buffer) - 1):
self.buffer[i + 1] = ALARM_COMPONENT_DISABLED
frequency_name = value[1]
error_message = "%s is not a supported frequency" % frequency_name
if frequency_name not in FREQUENCY:
raise ValueError(error_message)
frequency = FREQUENCY.index(frequency_name)
if frequency <= 1 and not self.has_seconds:
raise ValueError(error_message)
# i is the index of the minute byte
i = 2 if self.has_seconds else 1
if frequency > 0 and self.has_seconds: # minutely at least
self.buffer[1] = _bin2bcd(value[0].tm_sec)
if frequency > 1: # hourly at least
self.buffer[i] = _bin2bcd(value[0].tm_min)
if frequency > 2: # daily at least
self.buffer[i + 1] = _bin2bcd(value[0].tm_hour)
if value[1] == "weekly":
if self.weekday_shared:
self.buffer[i + 2] = (
_bin2bcd(value[0].tm_wday + self.weekday_start) | 0x40
)
else:
self.buffer[i + 3] = _bin2bcd(value[0].tm_wday + self.weekday_start)
elif value[1] == "monthly":
self.buffer[i + 2] = _bin2bcd(value[0].tm_mday)
with obj.i2c_device:
obj.i2c_device.write(self.buffer)