Shell - DMX Bricklet

This is the description of the Shell API bindings for the DMX Bricklet. General information and technical specifications for the DMX 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 DMX Bricklet

# Configure Bricklet as DMX master
tinkerforge call dmx-bricklet $uid set-dmx-mode dmx-mode-master

# Write DMX frame with 3 channels
tinkerforge call dmx-bricklet $uid write-frame 255,128,0

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 dmx-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the DMX 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 DMX Bricklet and exits
tinkerforge dispatch dmx-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the DMX 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 DMX Bricklet and exits
tinkerforge call dmx-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 dmx-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 dmx-bricklet <uid> set-dmx-mode <dmx-mode>
Parameters:
  • <dmx-mode> -- int (has symbols)
Output:

no output

Sets the DMX mode to either master or slave.

Calling this function sets frame number to 0.

The default value is 0 (master).

The following symbols are available for this function:

  • dmx-mode-master = 0, for <dmx-mode>
  • dmx-mode-slave = 1, for <dmx-mode>
tinkerforge call dmx-bricklet <uid> get-dmx-mode
Output:
  • dmx-mode -- int (has symbols)

Returns the DMX mode, as set by set-dmx-mode.

The following symbols are available for this function:

  • dmx-mode-master = 0, for dmx-mode
  • dmx-mode-slave = 1, for dmx-mode
tinkerforge call dmx-bricklet <uid> write-frame-low-level <frame-length> <frame-chunk-offset> <frame-chunk-data>
Parameters:
  • <frame-length> -- int
  • <frame-chunk-offset> -- int
  • <frame-chunk-data> -- int,int,..57x..,int
Output:

no output

Writes a DMX frame. The maximum frame size is 512 byte. Each byte represents one channel.

The next frame can be written after the frame-started callback was called. The frame is double buffered, so a new frame can be written as soon as the writing of the prior frame starts.

The data will be transfered when the next frame duration ends, see set-frame-duration.

Generic approach:

  • Set the frame duration to a value that represents the number of frames per second you want to achieve.
  • Set channels for first frame.
  • Wait for the frame-started callback.
  • Set channels for next frame.
  • Wait for the frame-started callback.
  • and so on.

This approach ensures that you can set new DMX data with a fixed frame rate.

This function can only be called in master mode.

tinkerforge call dmx-bricklet <uid> read-frame-low-level
Output:
  • frame-length -- int
  • frame-chunk-offset -- int
  • frame-chunk-data -- int,int,..53x..,int
  • frame-number -- int

Returns the last frame that was written by the DMX master. The size of the array is equivalent to the number of channels in the frame. Each byte represents one channel.

The next frame is available after the frame-available callback was called.

Generic approach:

  • Call read-frame to get first frame.
  • Wait for the frame-available callback.
  • Call read-frame to get second frame.
  • Wait for the frame-available callback.
  • and so on.

Instead of polling this function you can also use the frame callback. You can enable it with set-frame-callback-config.

The frame number starts at 0 and it is increased by one with each received frame.

This function can only be called in slave mode.

tinkerforge call dmx-bricklet <uid> set-frame-duration <frame-duration>
Parameters:
  • <frame-duration> -- int
Output:

no output

Sets the duration of a frame in ms.

Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).

If you always want to send a frame as fast as possible you can set this value to 0.

This setting is only used in master mode.

Default value: 100ms (10 frames per second).

tinkerforge call dmx-bricklet <uid> get-frame-duration
Output:
  • frame-duration -- int

Returns the frame duration as set by set-frame-duration.

Advanced Functions

tinkerforge call dmx-bricklet <uid> get-frame-error-count
Output:
  • overrun-error-count -- int
  • framing-error-count -- int

Returns the current number of overrun and framing errors.

tinkerforge call dmx-bricklet <uid> set-communication-led-config <config>
Parameters:
  • <config> -- int (has symbols)
Output:

no output

Sets the communication LED configuration. By default the LED shows communication traffic, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following symbols are available for this function:

  • communication-led-config-off = 0, for <config>
  • communication-led-config-on = 1, for <config>
  • communication-led-config-show-heartbeat = 2, for <config>
  • communication-led-config-show-communication = 3, for <config>
tinkerforge call dmx-bricklet <uid> get-communication-led-config
Output:
  • config -- int (has symbols)

Returns the configuration as set by set-communication-led-config

The following symbols are available for this function:

  • communication-led-config-off = 0, for config
  • communication-led-config-on = 1, for config
  • communication-led-config-show-heartbeat = 2, for config
  • communication-led-config-show-communication = 3, for config
tinkerforge call dmx-bricklet <uid> set-error-led-config <config>
Parameters:
  • <config> -- int (has symbols)
Output:

no output

Sets the error LED configuration.

By default the error LED turns on if there is any error (see frame-error-count callback). If you call this function with the Show-Error option again, the LED will turn off until the next error occurs.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following symbols are available for this function:

  • error-led-config-off = 0, for <config>
  • error-led-config-on = 1, for <config>
  • error-led-config-show-heartbeat = 2, for <config>
  • error-led-config-show-error = 3, for <config>
tinkerforge call dmx-bricklet <uid> get-error-led-config
Output:
  • config -- int (has symbols)

Returns the configuration as set by set-error-led-config.

The following symbols are available for this function:

  • error-led-config-off = 0, for config
  • error-led-config-on = 1, for config
  • error-led-config-show-heartbeat = 2, for config
  • error-led-config-show-error = 3, for config
tinkerforge call dmx-bricklet <uid> get-spitfp-error-count
Output:
  • error-count-ack-checksum -- int
  • error-count-message-checksum -- int
  • error-count-frame -- int
  • error-count-overflow -- int

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

tinkerforge call dmx-bricklet <uid> set-bootloader-mode <mode>
Parameters:
  • <mode> -- int (has symbols)
Output:
  • status -- int (has symbols)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following symbols are available for this function:

  • bootloader-mode-bootloader = 0, for <mode>
  • bootloader-mode-firmware = 1, for <mode>
  • bootloader-mode-bootloader-wait-for-reboot = 2, for <mode>
  • bootloader-mode-firmware-wait-for-reboot = 3, for <mode>
  • bootloader-mode-firmware-wait-for-erase-and-reboot = 4, for <mode>
  • bootloader-status-ok = 0, for status
  • bootloader-status-invalid-mode = 1, for status
  • bootloader-status-no-change = 2, for status
  • bootloader-status-entry-function-not-present = 3, for status
  • bootloader-status-device-identifier-incorrect = 4, for status
  • bootloader-status-crc-mismatch = 5, for status
tinkerforge call dmx-bricklet <uid> get-bootloader-mode
Output:
  • mode -- int (has symbols)

Returns the current bootloader mode, see set-bootloader-mode.

The following symbols are available for this function:

  • bootloader-mode-bootloader = 0, for mode
  • bootloader-mode-firmware = 1, for mode
  • bootloader-mode-bootloader-wait-for-reboot = 2, for mode
  • bootloader-mode-firmware-wait-for-reboot = 3, for mode
  • bootloader-mode-firmware-wait-for-erase-and-reboot = 4, for mode
tinkerforge call dmx-bricklet <uid> set-write-firmware-pointer <pointer>
Parameters:
  • <pointer> -- int
Output:

no output

Sets the firmware pointer for write-firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

tinkerforge call dmx-bricklet <uid> write-firmware <data>
Parameters:
  • <data> -- int,int,..61x..,int
Output:
  • status -- int

Writes 64 Bytes of firmware at the position as written by set-write-firmware-pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

tinkerforge call dmx-bricklet <uid> set-status-led-config <config>
Parameters:
  • <config> -- int (has symbols)
Output:

no output

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following symbols are available for this function:

  • status-led-config-off = 0, for <config>
  • status-led-config-on = 1, for <config>
  • status-led-config-show-heartbeat = 2, for <config>
  • status-led-config-show-status = 3, for <config>
tinkerforge call dmx-bricklet <uid> get-status-led-config
Output:
  • config -- int (has symbols)

Returns the configuration as set by set-status-led-config

The following symbols are available for this function:

  • status-led-config-off = 0, for config
  • status-led-config-on = 1, for config
  • status-led-config-show-heartbeat = 2, for config
  • status-led-config-show-status = 3, for config
tinkerforge call dmx-bricklet <uid> get-chip-temperature
Output:
  • temperature -- int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

tinkerforge call dmx-bricklet <uid> reset
Output:no output

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

tinkerforge call dmx-bricklet <uid> write-uid <uid>
Parameters:
  • <uid> -- int
Output:

no output

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

tinkerforge call dmx-bricklet <uid> read-uid
Output:
  • uid -- int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

tinkerforge call dmx-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 dmx-bricklet <uid> set-frame-callback-config <frame-started-callback-enabled> <frame-available-callback-enabled> <frame-callback-enabled> <frame-error-count-callback-enabled>
Parameters:
  • <frame-started-callback-enabled> -- bool
  • <frame-available-callback-enabled> -- bool
  • <frame-callback-enabled> -- bool
  • <frame-error-count-callback-enabled> -- bool
Output:

no output

Enables/Disables the different callbacks. By default the frame-started callback and frame-available callback are enabled while the frame callback and frame-error-count callback are disabled.

If you want to use the frame callback you can enable it and disable the cb:Frame Available callback at the same time. It becomes redundant in this case.

tinkerforge call dmx-bricklet <uid> get-frame-callback-config
Output:
  • frame-started-callback-enabled -- bool
  • frame-available-callback-enabled -- bool
  • frame-callback-enabled -- bool
  • frame-error-count-callback-enabled -- bool

Returns the frame callback config as set by set-frame-callback-config.

Callbacks

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

tinkerforge dispatch dmx-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 dmx-bricklet <uid> frame-started
Output:no output

This callback is triggered as soon as a new frame write is started. You should send the data for the next frame directly after this callback was triggered.

For an explanation of the general approach see write-frame.

This callback can be enabled via set-frame-callback-config.

This callback can only be triggered in master mode.

tinkerforge dispatch dmx-bricklet <uid> frame-available
Output:
  • frame-number -- int

This callback is triggered in slave mode when a new frame was received from the DMX master and it can be read out. You have to read the frame before the master has written the next frame, see read-frame for more details.

The parameter is the frame number, it is increased by one with each received frame.

This callback can be enabled via set-frame-callback-config.

This callback can only be triggered in slave mode.

tinkerforge dispatch dmx-bricklet <uid> frame-low-level
Output:
  • frame-length -- int
  • frame-chunk-offset -- int
  • frame-chunk-data -- int,int,..53x..,int
  • frame-number -- int

This callback is called as soon as a new frame is available (written by the DMX master).

The size of the array is equivalent to the number of channels in the frame. Each byte represents one channel.

This callback can be enabled via set-frame-callback-config.

This callback can only be triggered in slave mode.

tinkerforge dispatch dmx-bricklet <uid> frame-error-count
Output:
  • overrun-error-count -- int
  • framing-error-count -- int

This callback is called if a new error occurs. It returns the current overrun and framing error count.