Python - Real-Time Clock Bricklet¶

Simple¶

Download (example_simple.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Real-Time Clock Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_real_time_clock import BrickletRealTimeClock

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    rtc = BrickletRealTimeClock(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get current date and time
    year, month, day, hour, minute, second, centisecond, weekday = rtc.get_date_time()

    print("Year: " + str(year))
    print("Month: " + str(month))
    print("Day: " + str(day))
    print("Hour: " + str(hour))
    print("Minute: " + str(minute))
    print("Second: " + str(second))
    print("Centisecond: " + str(centisecond))

    if weekday == rtc.WEEKDAY_MONDAY:
        print("Weekday: Monday")
    elif weekday == rtc.WEEKDAY_TUESDAY:
        print("Weekday: Tuesday")
    elif weekday == rtc.WEEKDAY_WEDNESDAY:
        print("Weekday: Wednesday")
    elif weekday == rtc.WEEKDAY_THURSDAY:
        print("Weekday: Thursday")
    elif weekday == rtc.WEEKDAY_FRIDAY:
        print("Weekday: Friday")
    elif weekday == rtc.WEEKDAY_SATURDAY:
        print("Weekday: Saturday")
    elif weekday == rtc.WEEKDAY_SUNDAY:
        print("Weekday: Sunday")

    # Get current timestamp
    timestamp = rtc.get_timestamp()
    print("Timestamp: " + str(timestamp) + " ms")

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Callback¶

Download (example_callback.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your Real-Time Clock Bricklet

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_real_time_clock import BrickletRealTimeClock

# Callback function for date and time callback
def cb_date_time(year, month, day, hour, minute, second, centisecond, weekday, timestamp):
    print("Year: " + str(year))
    print("Month: " + str(month))
    print("Day: " + str(day))
    print("Hour: " + str(hour))
    print("Minute: " + str(minute))
    print("Second: " + str(second))
    print("Centisecond: " + str(centisecond))

    if weekday == BrickletRealTimeClock.WEEKDAY_MONDAY:
        print("Weekday: Monday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_TUESDAY:
        print("Weekday: Tuesday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_WEDNESDAY:
        print("Weekday: Wednesday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_THURSDAY:
        print("Weekday: Thursday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_FRIDAY:
        print("Weekday: Friday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_SATURDAY:
        print("Weekday: Saturday")
    elif weekday == BrickletRealTimeClock.WEEKDAY_SUNDAY:
        print("Weekday: Sunday")

    print("Timestamp: " + str(timestamp))
    print("")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    rtc = BrickletRealTimeClock(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register date and time callback to function cb_date_time
    rtc.register_callback(rtc.CALLBACK_DATE_TIME, cb_date_time)

    # Set period for date and time callback to 5s (5000ms)
    # Note: The date and time callback is only called every 5 seconds
    #       if the date and time has changed since the last call!
    rtc.set_date_time_callback_period(5000)

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Basic Functions¶

BrickletRealTimeClock(uid, ipcon)¶

Parameters:	uid – Type: str ipcon – Type: IPConnection
Returns:	real_time_clock – Type: BrickletRealTimeClock

Creates an object with the unique device ID uid:

real_time_clock = BrickletRealTimeClock("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected.

BrickletRealTimeClock.set_date_time(year, month, day, hour, minute, second, centisecond, weekday)¶

Parameters:	year – Type: int, Range: [2000 to 2099] month – Type: int, Range: [1 to 12] day – Type: int, Range: [1 to 31] hour – Type: int, Range: [0 to 23] minute – Type: int, Range: [0 to 59] second – Type: int, Range: [0 to 59] centisecond – Type: int, Range: [0 to 99] weekday – Type: int, Range: See constants
Returns:	None

Sets the current date (including weekday) and the current time.

If the backup battery is installed then the real-time clock keeps date and time even if the Bricklet is not powered by a Brick.

The real-time clock handles leap year and inserts the 29th of February accordingly. But leap seconds, time zones and daylight saving time are not handled.

The following constants are available for this function:

For weekday:

• BrickletRealTimeClock.WEEKDAY_MONDAY = 1
• BrickletRealTimeClock.WEEKDAY_TUESDAY = 2
• BrickletRealTimeClock.WEEKDAY_WEDNESDAY = 3
• BrickletRealTimeClock.WEEKDAY_THURSDAY = 4
• BrickletRealTimeClock.WEEKDAY_FRIDAY = 5
• BrickletRealTimeClock.WEEKDAY_SATURDAY = 6
• BrickletRealTimeClock.WEEKDAY_SUNDAY = 7

BrickletRealTimeClock.get_date_time()¶

Return Object:	year – Type: int, Range: [2000 to 2099] month – Type: int, Range: [1 to 12] day – Type: int, Range: [1 to 31] hour – Type: int, Range: [0 to 23] minute – Type: int, Range: [0 to 59] second – Type: int, Range: [0 to 59] centisecond – Type: int, Range: [0 to 99] weekday – Type: int, Range: See constants

Returns the current date (including weekday) and the current time of the real-time clock.

The following constants are available for this function:

For weekday:

• BrickletRealTimeClock.WEEKDAY_MONDAY = 1
• BrickletRealTimeClock.WEEKDAY_TUESDAY = 2
• BrickletRealTimeClock.WEEKDAY_WEDNESDAY = 3
• BrickletRealTimeClock.WEEKDAY_THURSDAY = 4
• BrickletRealTimeClock.WEEKDAY_FRIDAY = 5
• BrickletRealTimeClock.WEEKDAY_SATURDAY = 6
• BrickletRealTimeClock.WEEKDAY_SUNDAY = 7

BrickletRealTimeClock.get_timestamp()¶

Returns:	timestamp – Type: int, Unit: 1 ms, Range: [-263 to 263 - 1]

Returns the current date and the time of the real-time clock. The timestamp has an effective resolution of hundredths of a second and is an offset to 2000-01-01 00:00:00.000.

Advanced Functions¶

BrickletRealTimeClock.set_offset(offset)¶

Parameters:	offset – Type: int, Unit: 217/100 ppm, Range: [-128 to 127]
Returns:	None

Sets the offset the real-time clock should compensate for in 2.17 ppm steps between -277.76 ppm (-128) and +275.59 ppm (127).

The real-time clock time can deviate from the actual time due to the frequency deviation of its 32.768 kHz crystal. Even without compensation (factory default) the resulting time deviation should be at most ±20 ppm (±52.6 seconds per month).

This deviation can be calculated by comparing the same duration measured by the real-time clock (rtc_duration) an accurate reference clock (ref_duration).

For best results the configured offset should be set to 0 ppm first and then a duration of at least 6 hours should be measured.

The new offset (new_offset) can be calculated from the currently configured offset (current_offset) and the measured durations as follow:

new_offset = current_offset - round(1000000 * (rtc_duration - ref_duration) / rtc_duration / 2.17)

If you want to calculate the offset, then we recommend using the calibration dialog in Brick Viewer, instead of doing it manually.

The offset is saved in the EEPROM of the Bricklet and only needs to be configured once.

BrickletRealTimeClock.get_offset()¶

Returns:	offset – Type: int, Unit: 217/100 ppm, Range: [-128 to 127]

Returns the offset as set by set_offset().

BrickletRealTimeClock.get_identity()¶

Return Object:

uid – Type: str, Length: up to 8 connected_uid – Type: str, Length: up to 8 position – Type: chr, Range: ["a" to "h", "z"] hardware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] firmware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] device_identifier – Type: int, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions¶

BrickletRealTimeClock.register_callback(callback_id, function)¶

Parameters:	callback_id – Type: int function – Type: callable
Returns:	None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletRealTimeClock.set_date_time_callback_period(period)¶

Parameters:	period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:	None

Sets the period with which the CALLBACK_DATE_TIME callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_DATE_TIME Callback is only triggered if the date or time changed since the last triggering.

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.get_date_time_callback_period()¶

Returns:	period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by set_date_time_callback_period().

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.set_alarm(month, day, hour, minute, second, weekday, interval)¶

Parameters:

month – Type: int, Range: [-1, 1 to 12] with constants day – Type: int, Range: [-1, 1 to 31] with constants hour – Type: int, Range: [-1, 0 to 23] with constants minute – Type: int, Range: [-1, 0 to 59] with constants second – Type: int, Range: [-1, 0 to 59] with constants weekday – Type: int, Range: [-1, 1 to 7] with constants interval – Type: int, Unit: 1 s, Range: [-1, 1 to 231 - 1] with constants

Returns:

None

Configures a repeatable alarm. The CALLBACK_ALARM callback is triggered if the current date and time matches the configured alarm.

Setting a parameter to -1 means that it should be disabled and doesn't take part in the match. Setting all parameters to -1 disables the alarm completely.

For example, to make the alarm trigger every day at 7:30 AM it can be configured as (-1, -1, 7, 30, -1, -1, -1). The hour is set to match 7 and the minute is set to match 30. The alarm is triggered if all enabled parameters match.

The interval has a special role. It allows to make the alarm reconfigure itself. This is useful if you need a repeated alarm that cannot be expressed by matching the current date and time. For example, to make the alarm trigger every 23 seconds it can be configured as (-1, -1, -1, -1, -1, -1, 23). Internally the Bricklet will take the current date and time, add 23 seconds to it and set the result as its alarm. The first alarm will be triggered 23 seconds after the call. Because the interval is not -1, the Bricklet will do the same again internally, take the current date and time, add 23 seconds to it and set that as its alarm. This results in a repeated alarm that triggers every 23 seconds.

The interval can also be used in combination with the other parameters. For example, configuring the alarm as (-1, -1, 7, 30, -1, -1, 300) results in an alarm that triggers every day at 7:30 AM and is then repeated every 5 minutes.

The following constants are available for this function:

For month:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For day:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For hour:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For minute:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For second:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For weekday:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For interval:

• BrickletRealTimeClock.ALARM_INTERVAL_DISABLED = -1

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.get_alarm()¶

Return Object:

month – Type: int, Range: [-1, 1 to 12] with constants day – Type: int, Range: [-1, 1 to 31] with constants hour – Type: int, Range: [-1, 0 to 23] with constants minute – Type: int, Range: [-1, 0 to 59] with constants second – Type: int, Range: [-1, 0 to 59] with constants weekday – Type: int, Range: [-1, 1 to 7] with constants interval – Type: int, Unit: 1 s, Range: [-1, 1 to 231 - 1] with constants

Returns the alarm configuration as set by set_alarm().

The following constants are available for this function:

For month:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For day:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For hour:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For minute:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For second:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For weekday:

• BrickletRealTimeClock.ALARM_MATCH_DISABLED = -1

For interval:

• BrickletRealTimeClock.ALARM_INTERVAL_DISABLED = -1

New in version 2.0.1 (Plugin).

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

real_time_clock.register_callback(BrickletRealTimeClock.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters are described below.

BrickletRealTimeClock.CALLBACK_DATE_TIME¶

Callback Parameters:	year – Type: int, Range: [2000 to 2099] month – Type: int, Range: [1 to 12] day – Type: int, Range: [1 to 31] hour – Type: int, Range: [0 to 23] minute – Type: int, Range: [0 to 59] second – Type: int, Range: [0 to 59] centisecond – Type: int, Range: [0 to 99] weekday – Type: int, Range: See constants timestamp – Type: int, Unit: 1 ms, Range: [-263 to 263 - 1]

This callback is triggered periodically with the period that is set by set_date_time_callback_period(). The parameters are the same as for get_date_time() and get_timestamp() combined.

The CALLBACK_DATE_TIME callback is only triggered if the date or time changed since the last triggering.

The following constants are available for this function:

For weekday:

• BrickletRealTimeClock.WEEKDAY_MONDAY = 1
• BrickletRealTimeClock.WEEKDAY_TUESDAY = 2
• BrickletRealTimeClock.WEEKDAY_WEDNESDAY = 3
• BrickletRealTimeClock.WEEKDAY_THURSDAY = 4
• BrickletRealTimeClock.WEEKDAY_FRIDAY = 5
• BrickletRealTimeClock.WEEKDAY_SATURDAY = 6
• BrickletRealTimeClock.WEEKDAY_SUNDAY = 7

New in version 2.0.1 (Plugin).

BrickletRealTimeClock.CALLBACK_ALARM¶

Callback Parameters:	year – Type: int, Range: [2000 to 2099] month – Type: int, Range: [1 to 12] day – Type: int, Range: [1 to 31] hour – Type: int, Range: [0 to 23] minute – Type: int, Range: [0 to 59] second – Type: int, Range: [0 to 59] centisecond – Type: int, Range: [0 to 99] weekday – Type: int, Range: See constants timestamp – Type: int, Unit: 1 ms, Range: [-263 to 263 - 1]

This callback is triggered every time the current date and time matches the configured alarm (see set_alarm()). The parameters are the same as for get_date_time() and get_timestamp() combined.

The following constants are available for this function:

For weekday:

• BrickletRealTimeClock.WEEKDAY_MONDAY = 1
• BrickletRealTimeClock.WEEKDAY_TUESDAY = 2
• BrickletRealTimeClock.WEEKDAY_WEDNESDAY = 3
• BrickletRealTimeClock.WEEKDAY_THURSDAY = 4
• BrickletRealTimeClock.WEEKDAY_FRIDAY = 5
• BrickletRealTimeClock.WEEKDAY_SATURDAY = 6
• BrickletRealTimeClock.WEEKDAY_SUNDAY = 7

New in version 2.0.1 (Plugin).

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

BrickletRealTimeClock.get_api_version()¶

Return Object:	api_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletRealTimeClock.get_response_expected(function_id)¶

Parameters:	function_id – Type: int, Range: See constants
Returns:	response_expected – Type: bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

• BrickletRealTimeClock.FUNCTION_SET_DATE_TIME = 1
• BrickletRealTimeClock.FUNCTION_SET_OFFSET = 4
• BrickletRealTimeClock.FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 6
• BrickletRealTimeClock.FUNCTION_SET_ALARM = 8

BrickletRealTimeClock.set_response_expected(function_id, response_expected)¶

Parameters:	function_id – Type: int, Range: See constants response_expected – Type: bool
Returns:	None

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

• BrickletRealTimeClock.FUNCTION_SET_DATE_TIME = 1
• BrickletRealTimeClock.FUNCTION_SET_OFFSET = 4
• BrickletRealTimeClock.FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 6
• BrickletRealTimeClock.FUNCTION_SET_ALARM = 8

BrickletRealTimeClock.set_response_expected_all(response_expected)¶

Parameters:	response_expected – Type: bool
Returns:	None

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants¶

BrickletRealTimeClock.DEVICE_IDENTIFIER¶

This constant is used to identify a Real-Time Clock Bricklet.

The get_identity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletRealTimeClock.DEVICE_DISPLAY_NAME¶

This constant represents the human readable name of a Real-Time Clock Bricklet.