1 files changed, 202 insertions, 0 deletions
diff --git a/src/pico/adafruit_register/i2c_bcd_alarm.py b/src/pico/adafruit_register/i2c_bcd_alarm.py
new file mode 100755
index 0000000..74c8a77
--- /dev/null
+++ b/src/pico/adafruit_register/i2c_bcd_alarm.py
@@ -0,0 +1,202 @@
+# SPDX-FileCopyrightText: 2016 Scott Shawcroft for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+# pylint: disable=too-few-public-methods
+# pylint: disable=too-many-branches
+
+"""
+`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", "minutely", "secondly"
+    ]
+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"]
+
+
+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
+        else:
+            frequency = "minutely"
+            seconds = _bcd2bin(self.buffer[i] & 0x7F)
+        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)