Shell - Real-Time Clock Bricklet

This is the description of the Shell API bindings for the Real-Time Clock Bricklet. General information and technical specifications for the Real-Time Clock Bricklet are summarized in its hardware description.

An installation guide for the Shell API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Real-Time Clock Bricklet

# Get current date and time
tinkerforge call real-time-clock-bricklet $uid get-date-time

# Get current timestamp
tinkerforge call real-time-clock-bricklet $uid get-timestamp

Callback

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your Real-Time Clock Bricklet

# Handle incoming date and time callbacks
tinkerforge dispatch real-time-clock-bricklet $uid 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!
tinkerforge call real-time-clock-bricklet $uid set-date-time-callback-period 5000

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call real-time-clock-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the Real-Time Clock Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the Real-Time Clock Bricklet and exits
tinkerforge dispatch real-time-clock-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the Real-Time Clock Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the Real-Time Clock Bricklet and exits
tinkerforge call real-time-clock-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch real-time-clock-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call real-time-clock-bricklet <uid> set-date-time <year> <month> <day> <hour> <minute> <second> <centisecond> <weekday>
Parameters:
  • <year> -- int
  • <month> -- int
  • <day> -- int
  • <hour> -- int
  • <minute> -- int
  • <second> -- int
  • <centisecond> -- int
  • <weekday> -- int (has symbols)
Output:

no output

Sets the current date (including weekday) and the current time with hundredths of a second resolution.

Possible value ranges:

  • Year: 2000 to 2099
  • Month: 1 to 12 (January to December)
  • Day: 1 to 31
  • Hour: 0 to 23
  • Minute: 0 to 59
  • Second: 0 to 59
  • Centisecond: 0 to 99
  • Weekday: 1 to 7 (Monday to Sunday)

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 symbols are available for this function:

  • weekday-monday = 1, for <weekday>
  • weekday-tuesday = 2, for <weekday>
  • weekday-wednesday = 3, for <weekday>
  • weekday-thursday = 4, for <weekday>
  • weekday-friday = 5, for <weekday>
  • weekday-saturday = 6, for <weekday>
  • weekday-sunday = 7, for <weekday>
tinkerforge call real-time-clock-bricklet <uid> get-date-time
Output:
  • year -- int
  • month -- int
  • day -- int
  • hour -- int
  • minute -- int
  • second -- int
  • centisecond -- int
  • weekday -- int (has symbols)

Returns the current date (including weekday) and the current time of the real-time clock with hundredths of a second resolution.

The following symbols are available for this function:

  • weekday-monday = 1, for weekday
  • weekday-tuesday = 2, for weekday
  • weekday-wednesday = 3, for weekday
  • weekday-thursday = 4, for weekday
  • weekday-friday = 5, for weekday
  • weekday-saturday = 6, for weekday
  • weekday-sunday = 7, for weekday
tinkerforge call real-time-clock-bricklet <uid> get-timestamp
Output:
  • timestamp -- int

Returns the current date and the time of the real-time clock converted to milliseconds. The timestamp has an effective resolution of hundredths of a second.

Advanced Functions

tinkerforge call real-time-clock-bricklet <uid> set-offset <offset>
Parameters:
  • <offset> -- int
Output:

no output

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.

tinkerforge call real-time-clock-bricklet <uid> get-offset
Output:
  • offset -- int

Returns the offset as set by set-offset.

tinkerforge call real-time-clock-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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' or 'd'.

The device identifier numbers can be found here

Callback Configuration Functions

tinkerforge call real-time-clock-bricklet <uid> set-date-time-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

Sets the period in ms with which the date-time callback is triggered periodically. A value of 0 turns the callback off.

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

The default value is 0.

New in version 2.0.1 (Plugin).

tinkerforge call real-time-clock-bricklet <uid> get-date-time-callback-period
Output:
  • period -- int

Returns the period as set by set-date-time-callback-period.

New in version 2.0.1 (Plugin).

tinkerforge call real-time-clock-bricklet <uid> set-alarm <month> <day> <hour> <minute> <second> <weekday> <interval>
Parameters:
  • <month> -- int (has symbols)
  • <day> -- int (has symbols)
  • <hour> -- int (has symbols)
  • <minute> -- int (has symbols)
  • <second> -- int (has symbols)
  • <weekday> -- int (has symbols)
  • <interval> -- int (has symbols)
Output:

no output

Configures a repeatable alarm. The 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 symbols are available for this function:

  • alarm-match-disabled = -1, for <month>, <day>, <hour>, <minute>, <second> and <weekday>
  • alarm-interval-disabled = -1, for <interval>

New in version 2.0.1 (Plugin).

tinkerforge call real-time-clock-bricklet <uid> get-alarm
Output:
  • month -- int (has symbols)
  • day -- int (has symbols)
  • hour -- int (has symbols)
  • minute -- int (has symbols)
  • second -- int (has symbols)
  • weekday -- int (has symbols)
  • interval -- int (has symbols)

Returns the alarm configuration as set by set-alarm.

The following symbols are available for this function:

  • alarm-match-disabled = -1, for month, day, hour, minute, second and weekday
  • alarm-interval-disabled = -1, for interval

New in version 2.0.1 (Plugin).

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch real-time-clock-bricklet <uid> example

The available callbacks are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

tinkerforge dispatch real-time-clock-bricklet <uid> date-time
Output:
  • year -- int
  • month -- int
  • day -- int
  • hour -- int
  • minute -- int
  • second -- int
  • centisecond -- int
  • weekday -- int (has symbols)
  • timestamp -- int

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

The following symbols are available for this function:

  • weekday-monday = 1, for weekday
  • weekday-tuesday = 2, for weekday
  • weekday-wednesday = 3, for weekday
  • weekday-thursday = 4, for weekday
  • weekday-friday = 5, for weekday
  • weekday-saturday = 6, for weekday
  • weekday-sunday = 7, for weekday

New in version 2.0.1 (Plugin).

tinkerforge dispatch real-time-clock-bricklet <uid> alarm
Output:
  • year -- int
  • month -- int
  • day -- int
  • hour -- int
  • minute -- int
  • second -- int
  • centisecond -- int
  • weekday -- int (has symbols)
  • timestamp -- int

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 symbols are available for this function:

  • weekday-monday = 1, for weekday
  • weekday-tuesday = 2, for weekday
  • weekday-wednesday = 3, for weekday
  • weekday-thursday = 4, for weekday
  • weekday-friday = 5, for weekday
  • weekday-saturday = 6, for weekday
  • weekday-sunday = 7, for weekday

New in version 2.0.1 (Plugin).