Go - DMX Bricklet

This is the description of the Go 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 Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Simple

Download (example_simple.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/dmx_bricklet"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your DMX Bricklet.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    dmx, _ := dmx_bricklet.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Configure Bricklet as DMX master
    dmx.SetDMXMode(dmx_bricklet.DMXModeMaster)

    // Write DMX frame with 3 channels
    dmx.WriteFrame([]uint8{255, 128, 0})

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The DMX Bricklet's API is defined in the package github.com/Tinkerforge/go-api-bindings/dmx_bricklet

Nearly every function of the Go bindings can return an BrickletError, implementing the error interface. The error can have one of the following values:

  • BrickletErrorSuccess = 0
  • BrickletErrorInvalidParameter = 1
  • BrickletErrorFunctionNotSupported = 2
  • BrickletErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func NewDMXBricklet(uid string, ipcon *IPConnection)(device DMXBricklet, err error)

Creates a new DMXBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

This device object can be used after the IP connection has been connected (see examples above).

func (*DMXBricklet)SetDMXMode(dmxMode DMXMode)(err error)

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 constants are available for this function:

  • DMXModeMaster = 0
  • DMXModeSlave = 1
func (*DMXBricklet)GetDMXMode()(dmxMode DMXMode, err error)

Returns the DMX mode, as set by (*DMXBricklet) SetDMXMode.

The following constants are available for this function:

  • DMXModeMaster = 0
  • DMXModeSlave = 1
func (*DMXBricklet)WriteFrame(frame []uint8)(err error)

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

The next frame can be written after the (*DMXBricklet) RegisterFrameStartedCallback 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 (*DMXBricklet) SetFrameDuration.

Generic approach:

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

This function can only be called in master mode.

func (*DMXBricklet)ReadFrame()(frame []uint8, frameNumber uint32, err error)

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 (*DMXBricklet) RegisterFrameAvailableCallback callback was called.

Generic approach:

Instead of polling this function you can also use the (*DMXBricklet) RegisterFrameCallback callback. You can enable it with (*DMXBricklet) SetFrameCallbackConfig.

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.

func (*DMXBricklet)SetFrameDuration(frameDuration uint16)(err error)

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).

func (*DMXBricklet)GetFrameDuration()(frameDuration uint16, err error)

Returns the frame duration as set by (*DMXBricklet) SetFrameDuration.

Advanced Functions

func (*DMXBricklet)GetFrameErrorCount()(overrunErrorCount uint32, framingErrorCount uint32, err error)

Returns the current number of overrun and framing errors.

func (*DMXBricklet)SetCommunicationLEDConfig(config CommunicationLEDConfig)(err error)

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 constants are available for this function:

  • CommunicationLEDConfigOff = 0
  • CommunicationLEDConfigOn = 1
  • CommunicationLEDConfigShowHeartbeat = 2
  • CommunicationLEDConfigShowCommunication = 3
func (*DMXBricklet)GetCommunicationLEDConfig()(config CommunicationLEDConfig, err error)

Returns the configuration as set by (*DMXBricklet) SetCommunicationLEDConfig

The following constants are available for this function:

  • CommunicationLEDConfigOff = 0
  • CommunicationLEDConfigOn = 1
  • CommunicationLEDConfigShowHeartbeat = 2
  • CommunicationLEDConfigShowCommunication = 3
func (*DMXBricklet)SetErrorLEDConfig(config ErrorLEDConfig)(err error)

Sets the error LED configuration.

By default the error LED turns on if there is any error (see (*DMXBricklet) RegisterFrameErrorCountCallback 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 constants are available for this function:

  • ErrorLEDConfigOff = 0
  • ErrorLEDConfigOn = 1
  • ErrorLEDConfigShowHeartbeat = 2
  • ErrorLEDConfigShowError = 3
func (*DMXBricklet)GetErrorLEDConfig()(config ErrorLEDConfig, err error)

Returns the configuration as set by (*DMXBricklet) SetErrorLEDConfig.

The following constants are available for this function:

  • ErrorLEDConfigOff = 0
  • ErrorLEDConfigOn = 1
  • ErrorLEDConfigShowHeartbeat = 2
  • ErrorLEDConfigShowError = 3
func (*DMXBricklet)GetAPIVersion()(apiVersion [3]uint8, err error)

Returns the version of the API definition (major, minor, revision) 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.

func (*DMXBricklet)GetResponseExpected(functionId uint8)(responseExpected bool, err error)

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 (*DMXBricklet) SetResponseExpected. 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 send and errors are silently ignored, because they cannot be detected.

See (*DMXBricklet) SetResponseExpected for the list of function ID constants available for this function.

func (*DMXBricklet)SetResponseExpected(functionId uint8, responseExpected bool)(err error)

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 send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • FunctionSetDMXMode = 1
  • FunctionWriteFrame = 3
  • FunctionSetFrameDuration = 5
  • FunctionSetCommunicationLEDConfig = 8
  • FunctionSetErrorLEDConfig = 10
  • FunctionSetFrameCallbackConfig = 12
  • FunctionSetWriteFirmwarePointer = 237
  • FunctionSetStatusLEDConfig = 239
  • FunctionReset = 243
  • FunctionWriteUID = 248
func (*DMXBricklet)SetResponseExpectedAll(responseExpected bool)(err error)

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

func (*DMXBricklet)GetSPITFPErrorCount()(errorCountAckChecksum uint32, errorCountMessageChecksum uint32, errorCountFrame uint32, errorCountOverflow uint32, err error)

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.

func (*DMXBricklet)SetBootloaderMode(mode BootloaderMode)(status BootloaderStatus, err error)

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 constants are available for this function:

  • BootloaderModeBootloader = 0
  • BootloaderModeFirmware = 1
  • BootloaderModeBootloaderWaitForReboot = 2
  • BootloaderModeFirmwareWaitForReboot = 3
  • BootloaderModeFirmwareWaitForEraseAndReboot = 4
  • BootloaderStatusOK = 0
  • BootloaderStatusInvalidMode = 1
  • BootloaderStatusNoChange = 2
  • BootloaderStatusEntryFunctionNotPresent = 3
  • BootloaderStatusDeviceIdentifierIncorrect = 4
  • BootloaderStatusCRCMismatch = 5
func (*DMXBricklet)GetBootloaderMode()(mode BootloaderMode, err error)

Returns the current bootloader mode, see (*DMXBricklet) SetBootloaderMode.

The following constants are available for this function:

  • BootloaderModeBootloader = 0
  • BootloaderModeFirmware = 1
  • BootloaderModeBootloaderWaitForReboot = 2
  • BootloaderModeFirmwareWaitForReboot = 3
  • BootloaderModeFirmwareWaitForEraseAndReboot = 4
func (*DMXBricklet)SetWriteFirmwarePointer(pointer uint32)(err error)

Sets the firmware pointer for (*DMXBricklet) WriteFirmware. 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.

func (*DMXBricklet)WriteFirmware(data [64]uint8)(status uint8, err error)

Writes 64 Bytes of firmware at the position as written by (*DMXBricklet) SetWriteFirmwarePointer 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.

func (*DMXBricklet)SetStatusLEDConfig(config StatusLEDConfig)(err error)

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 constants are available for this function:

  • StatusLEDConfigOff = 0
  • StatusLEDConfigOn = 1
  • StatusLEDConfigShowHeartbeat = 2
  • StatusLEDConfigShowStatus = 3
func (*DMXBricklet)GetStatusLEDConfig()(config StatusLEDConfig, err error)

Returns the configuration as set by (*DMXBricklet) SetStatusLEDConfig

The following constants are available for this function:

  • StatusLEDConfigOff = 0
  • StatusLEDConfigOn = 1
  • StatusLEDConfigShowHeartbeat = 2
  • StatusLEDConfigShowStatus = 3
func (*DMXBricklet)GetChipTemperature()(temperature int16, err error)

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.

func (*DMXBricklet)Reset()(err error)

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!

func (*DMXBricklet)WriteUID(uid uint32)(err error)

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.

func (*DMXBricklet)ReadUID()(uid uint32, err error)

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

func (*DMXBricklet)GetIdentity()(uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)

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. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

func (*DMXBricklet)SetFrameCallbackConfig(frameStartedCallbackEnabled bool, frameAvailableCallbackEnabled bool, frameCallbackEnabled bool, frameErrorCountCallbackEnabled bool)(err error)

Enables/Disables the different callbacks. By default the (*DMXBricklet) RegisterFrameStartedCallback callback and (*DMXBricklet) RegisterFrameAvailableCallback callback are enabled while the (*DMXBricklet) RegisterFrameCallback callback and (*DMXBricklet) RegisterFrameErrorCountCallback callback are disabled.

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

func (*DMXBricklet)GetFrameCallbackConfig()(frameStartedCallbackEnabled bool, frameAvailableCallbackEnabled bool, frameCallbackEnabled bool, frameErrorCountCallbackEnabled bool, err error)

Returns the frame callback config as set by (*DMXBricklet) SetFrameCallbackConfig.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later.

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.

func (*DMXBricklet)RegisterFrameStartedCallback(func())(registrationID uint64)

A callback can be registered for this event with the RegisterFrameStartedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterFrameStartedCallback(registrationID uint64) function.

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 (*DMXBricklet) WriteFrame.

This callback can be enabled via (*DMXBricklet) SetFrameCallbackConfig.

This callback can only be triggered in master mode.

func (*DMXBricklet)RegisterFrameAvailableCallback(func(frameNumber uint32))(registrationID uint64)

A callback can be registered for this event with the RegisterFrameAvailableCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterFrameAvailableCallback(registrationID uint64) function.

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 (*DMXBricklet) ReadFrame for more details.

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

This callback can be enabled via (*DMXBricklet) SetFrameCallbackConfig.

This callback can only be triggered in slave mode.

func (*DMXBricklet)RegisterFrameCallback(func(frame []uint8, frameNumber uint32))(registrationID uint64)

A callback can be registered for this event with the RegisterFrameCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterFrameCallback(registrationID uint64) function.

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 (*DMXBricklet) SetFrameCallbackConfig.

This callback can only be triggered in slave mode.

func (*DMXBricklet)RegisterFrameErrorCountCallback(func(overrunErrorCount uint32, framingErrorCount uint32))(registrationID uint64)

A callback can be registered for this event with the RegisterFrameErrorCountCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterFrameErrorCountCallback(registrationID uint64) function.

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

Constants

dmx_bricklet.DeviceIdentifier

This constant is used to identify a DMX Bricklet.

The (*DMXBricklet) GetIdentity function and the (*IPConnection) RegisterEnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

dmx_bricklet.DeviceDisplayName

This constant represents the human readable name of a DMX Bricklet.