Go - LED Strip Bricklet 2.0

This is the description of the Go API bindings for the LED Strip Bricklet 2.0. General information and technical specifications for the LED Strip Bricklet 2.0 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/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/led_strip_v2_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your LED Strip Bricklet 2.0.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    ls, _ := led_strip_v2_bricklet.New(UID, &ipcon) // Create device object.

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

    // Set first 3 LEDs to red, green and blue
    ls.SetLEDValues(0, []uint8{255, 0, 0, 0, 255, 0, 0, 0, 255})

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

Callback

Download (example_callback.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/led_strip_v2_bricklet"
)

// FIXME: This example is incomplete

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your LED Strip Bricklet 2.0.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    ls, _ := led_strip_v2_bricklet.New(UID, &ipcon) // Create device object.

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

    // Set frame duration to 50ms (20 frames per second)
    ls.SetFrameDuration(50)

    ls.RegisterFrameStartedCallback(func(length uint16) {
        fmt.Println("Length: ", length)
    })

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

API

The LED Strip Bricklet 2.0 API is defined in the package github.com/Tinkerforge/go-api-bindings/led_strip_v2_bricklet

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

  • DeviceErrorSuccess = 0
  • DeviceErrorInvalidParameter = 1
  • DeviceErrorFunctionNotSupported = 2
  • DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func led_strip_v2_bricklet.New(uid string, ipcon *IPConnection) (device LEDStripV2Bricklet, err error)

Creates a new LEDStripV2Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := led_strip_v2_bricklet.New("YOUR_DEVICE_UID", &ipcon)

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

func (*LEDStripV2Bricklet) SetLEDValues(index uint16, value []uint8) (err error)

Sets the RGB(W) values for the LEDs starting from index. You can set at most 2048 RGB values or 1536 RGBW values.

To make the colors show correctly you need to configure the chip type (see SetChipType()) and a channel mapping (see SetChannelMapping()) according to the connected LEDs.

If the channel mapping has 3 colors, you need to give the data in the sequence RGBRGBRGB... if the channel mapping has 4 colors you need to give data in the sequence RGBWRGBWRGBW...

The data is double buffered and the colors will be transfered to the LEDs when the next frame duration ends (see SetFrameDuration()).

Generic approach:

  • Set the frame duration to a value that represents the number of frames per second you want to achieve.
  • Set all of the LED colors for one frame.
  • Wait for the RegisterFrameStartedCallback callback.
  • Set all of the LED colors for next frame.
  • Wait for the RegisterFrameStartedCallback callback.
  • And so on.

This approach ensures that you can change the LED colors with a fixed frame rate.

func (*LEDStripV2Bricklet) GetLEDValues(index uint16, length uint16) (value []uint8, err error)

Returns the RGB(W) values as set by SetLEDValues().

func (*LEDStripV2Bricklet) SetFrameDuration(duration uint16) (err error)

Sets the frame duration in ms.

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

For an explanation of the general approach see SetLEDValues().

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

func (*LEDStripV2Bricklet) GetFrameDuration() (duration uint16, err error)

Returns the frame duration in ms as set by SetFrameDuration().

func (*LEDStripV2Bricklet) GetSupplyVoltage() (voltage uint16, err error)

Returns the current supply voltage of the LEDs. The voltage is given in mV.

func (*LEDStripV2Bricklet) SetClockFrequency(frequency uint32) (err error)

Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).

The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling GetClockFrequency().

If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.

With a decreasing frequency your maximum frames per second will decrease too.

The default value is 1.66MHz.

func (*LEDStripV2Bricklet) GetClockFrequency() (frequency uint32, err error)

Returns the currently used clock frequency as set by SetClockFrequency().

func (*LEDStripV2Bricklet) SetChipType(chip ChipType) (err error)

Sets the type of the LED driver chip. We currently support the chips

  • WS2801,
  • WS2811,
  • WS2812 / SK6812 / NeoPixel RGB,
  • SK6812RGBW / NeoPixel RGBW (Chip Type = WS2812),
  • LPD8806 and
  • APA102 / DotStar.

The default value is WS2801 (2801).

The following constants are available for this function:

  • led_strip_v2_bricklet.ChipTypeWS2801 = 2801
  • led_strip_v2_bricklet.ChipTypeWS2811 = 2811
  • led_strip_v2_bricklet.ChipTypeWS2812 = 2812
  • led_strip_v2_bricklet.ChipTypeLPD8806 = 8806
  • led_strip_v2_bricklet.ChipTypeAPA102 = 102
func (*LEDStripV2Bricklet) GetChipType() (chip ChipType, err error)

Returns the currently used chip type as set by SetChipType().

The following constants are available for this function:

  • led_strip_v2_bricklet.ChipTypeWS2801 = 2801
  • led_strip_v2_bricklet.ChipTypeWS2811 = 2811
  • led_strip_v2_bricklet.ChipTypeWS2812 = 2812
  • led_strip_v2_bricklet.ChipTypeLPD8806 = 8806
  • led_strip_v2_bricklet.ChipTypeAPA102 = 102
func (*LEDStripV2Bricklet) SetChannelMapping(mapping ChannelMapping) (err error)

Sets the channel mapping for the connected LEDs.

If the mapping has 4 colors, the function SetLEDValues() expects 4 values per pixel and if the mapping has 3 colors it expects 3 values per pixel.

The function always expects the order RGB(W). The connected LED driver chips might have their 3 or 4 channels in a different order. For example, the WS2801 chips typically use BGR order, then WS2812 chips typically use GRB order and the APA102 chips typically use WBGR order.

The APA102 chips are special. They have three 8-bit channels for RGB and an additional 5-bit channel for the overall brightness of the RGB LED making them 4-channel chips. Internally the brightness channel is the first channel, therefore one of the Wxyz channel mappings should be used. Then the W channel controls the brightness.

The default value is BGR (36).

The following constants are available for this function:

  • led_strip_v2_bricklet.ChannelMappingRGB = 6
  • led_strip_v2_bricklet.ChannelMappingRBG = 9
  • led_strip_v2_bricklet.ChannelMappingBRG = 33
  • led_strip_v2_bricklet.ChannelMappingBGR = 36
  • led_strip_v2_bricklet.ChannelMappingGRB = 18
  • led_strip_v2_bricklet.ChannelMappingGBR = 24
  • led_strip_v2_bricklet.ChannelMappingRGBW = 27
  • led_strip_v2_bricklet.ChannelMappingRGWB = 30
  • led_strip_v2_bricklet.ChannelMappingRBGW = 39
  • led_strip_v2_bricklet.ChannelMappingRBWG = 45
  • led_strip_v2_bricklet.ChannelMappingRWGB = 54
  • led_strip_v2_bricklet.ChannelMappingRWBG = 57
  • led_strip_v2_bricklet.ChannelMappingGRWB = 78
  • led_strip_v2_bricklet.ChannelMappingGRBW = 75
  • led_strip_v2_bricklet.ChannelMappingGBWR = 108
  • led_strip_v2_bricklet.ChannelMappingGBRW = 99
  • led_strip_v2_bricklet.ChannelMappingGWBR = 120
  • led_strip_v2_bricklet.ChannelMappingGWRB = 114
  • led_strip_v2_bricklet.ChannelMappingBRGW = 135
  • led_strip_v2_bricklet.ChannelMappingBRWG = 141
  • led_strip_v2_bricklet.ChannelMappingBGRW = 147
  • led_strip_v2_bricklet.ChannelMappingBGWR = 156
  • led_strip_v2_bricklet.ChannelMappingBWRG = 177
  • led_strip_v2_bricklet.ChannelMappingBWGR = 180
  • led_strip_v2_bricklet.ChannelMappingWRBG = 201
  • led_strip_v2_bricklet.ChannelMappingWRGB = 198
  • led_strip_v2_bricklet.ChannelMappingWGBR = 216
  • led_strip_v2_bricklet.ChannelMappingWGRB = 210
  • led_strip_v2_bricklet.ChannelMappingWBGR = 228
  • led_strip_v2_bricklet.ChannelMappingWBRG = 225
func (*LEDStripV2Bricklet) GetChannelMapping() (mapping ChannelMapping, err error)

Returns the currently used channel mapping as set by SetChannelMapping().

The following constants are available for this function:

  • led_strip_v2_bricklet.ChannelMappingRGB = 6
  • led_strip_v2_bricklet.ChannelMappingRBG = 9
  • led_strip_v2_bricklet.ChannelMappingBRG = 33
  • led_strip_v2_bricklet.ChannelMappingBGR = 36
  • led_strip_v2_bricklet.ChannelMappingGRB = 18
  • led_strip_v2_bricklet.ChannelMappingGBR = 24
  • led_strip_v2_bricklet.ChannelMappingRGBW = 27
  • led_strip_v2_bricklet.ChannelMappingRGWB = 30
  • led_strip_v2_bricklet.ChannelMappingRBGW = 39
  • led_strip_v2_bricklet.ChannelMappingRBWG = 45
  • led_strip_v2_bricklet.ChannelMappingRWGB = 54
  • led_strip_v2_bricklet.ChannelMappingRWBG = 57
  • led_strip_v2_bricklet.ChannelMappingGRWB = 78
  • led_strip_v2_bricklet.ChannelMappingGRBW = 75
  • led_strip_v2_bricklet.ChannelMappingGBWR = 108
  • led_strip_v2_bricklet.ChannelMappingGBRW = 99
  • led_strip_v2_bricklet.ChannelMappingGWBR = 120
  • led_strip_v2_bricklet.ChannelMappingGWRB = 114
  • led_strip_v2_bricklet.ChannelMappingBRGW = 135
  • led_strip_v2_bricklet.ChannelMappingBRWG = 141
  • led_strip_v2_bricklet.ChannelMappingBGRW = 147
  • led_strip_v2_bricklet.ChannelMappingBGWR = 156
  • led_strip_v2_bricklet.ChannelMappingBWRG = 177
  • led_strip_v2_bricklet.ChannelMappingBWGR = 180
  • led_strip_v2_bricklet.ChannelMappingWRBG = 201
  • led_strip_v2_bricklet.ChannelMappingWRGB = 198
  • led_strip_v2_bricklet.ChannelMappingWGBR = 216
  • led_strip_v2_bricklet.ChannelMappingWGRB = 210
  • led_strip_v2_bricklet.ChannelMappingWBGR = 228
  • led_strip_v2_bricklet.ChannelMappingWBRG = 225

Advanced Functions

func (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) GetResponseExpected(functionId Function) (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 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.

The following constants are available for this function:

  • led_strip_v2_bricklet.FunctionSetLEDValues = 1
  • led_strip_v2_bricklet.FunctionSetFrameDuration = 3
  • led_strip_v2_bricklet.FunctionSetClockFrequency = 7
  • led_strip_v2_bricklet.FunctionSetChipType = 9
  • led_strip_v2_bricklet.FunctionSetChannelMapping = 11
  • led_strip_v2_bricklet.FunctionSetFrameStartedCallbackConfiguration = 13
  • led_strip_v2_bricklet.FunctionSetWriteFirmwarePointer = 237
  • led_strip_v2_bricklet.FunctionSetStatusLEDConfig = 239
  • led_strip_v2_bricklet.FunctionReset = 243
  • led_strip_v2_bricklet.FunctionWriteUID = 248
func (*LEDStripV2Bricklet) SetResponseExpected(functionId Function, 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 constants are available for this function:

  • led_strip_v2_bricklet.FunctionSetLEDValues = 1
  • led_strip_v2_bricklet.FunctionSetFrameDuration = 3
  • led_strip_v2_bricklet.FunctionSetClockFrequency = 7
  • led_strip_v2_bricklet.FunctionSetChipType = 9
  • led_strip_v2_bricklet.FunctionSetChannelMapping = 11
  • led_strip_v2_bricklet.FunctionSetFrameStartedCallbackConfiguration = 13
  • led_strip_v2_bricklet.FunctionSetWriteFirmwarePointer = 237
  • led_strip_v2_bricklet.FunctionSetStatusLEDConfig = 239
  • led_strip_v2_bricklet.FunctionReset = 243
  • led_strip_v2_bricklet.FunctionWriteUID = 248
func (*LEDStripV2Bricklet) SetResponseExpectedAll(responseExpected bool) (err error)

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

func (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) 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:

  • led_strip_v2_bricklet.BootloaderModeBootloader = 0
  • led_strip_v2_bricklet.BootloaderModeFirmware = 1
  • led_strip_v2_bricklet.BootloaderModeBootloaderWaitForReboot = 2
  • led_strip_v2_bricklet.BootloaderModeFirmwareWaitForReboot = 3
  • led_strip_v2_bricklet.BootloaderModeFirmwareWaitForEraseAndReboot = 4
  • led_strip_v2_bricklet.BootloaderStatusOK = 0
  • led_strip_v2_bricklet.BootloaderStatusInvalidMode = 1
  • led_strip_v2_bricklet.BootloaderStatusNoChange = 2
  • led_strip_v2_bricklet.BootloaderStatusEntryFunctionNotPresent = 3
  • led_strip_v2_bricklet.BootloaderStatusDeviceIdentifierIncorrect = 4
  • led_strip_v2_bricklet.BootloaderStatusCRCMismatch = 5
func (*LEDStripV2Bricklet) GetBootloaderMode() (mode BootloaderMode, err error)

Returns the current bootloader mode, see SetBootloaderMode().

The following constants are available for this function:

  • led_strip_v2_bricklet.BootloaderModeBootloader = 0
  • led_strip_v2_bricklet.BootloaderModeFirmware = 1
  • led_strip_v2_bricklet.BootloaderModeBootloaderWaitForReboot = 2
  • led_strip_v2_bricklet.BootloaderModeFirmwareWaitForReboot = 3
  • led_strip_v2_bricklet.BootloaderModeFirmwareWaitForEraseAndReboot = 4
func (*LEDStripV2Bricklet) SetWriteFirmwarePointer(pointer uint32) (err error)

Sets the firmware pointer for 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 (*LEDStripV2Bricklet) WriteFirmware(data [64]uint8) (status uint8, err error)

Writes 64 Bytes of firmware at the position as written by 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 (*LEDStripV2Bricklet) 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:

  • led_strip_v2_bricklet.StatusLEDConfigOff = 0
  • led_strip_v2_bricklet.StatusLEDConfigOn = 1
  • led_strip_v2_bricklet.StatusLEDConfigShowHeartbeat = 2
  • led_strip_v2_bricklet.StatusLEDConfigShowStatus = 3
func (*LEDStripV2Bricklet) GetStatusLEDConfig() (config StatusLEDConfig, err error)

Returns the configuration as set by SetStatusLEDConfig()

The following constants are available for this function:

  • led_strip_v2_bricklet.StatusLEDConfigOff = 0
  • led_strip_v2_bricklet.StatusLEDConfigOn = 1
  • led_strip_v2_bricklet.StatusLEDConfigShowHeartbeat = 2
  • led_strip_v2_bricklet.StatusLEDConfigShowStatus = 3
func (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) ReadUID() (uid uint32, err error)

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

func (*LEDStripV2Bricklet) 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 (*LEDStripV2Bricklet) SetFrameStartedCallbackConfiguration(enable bool) (err error)

Enables/disables the RegisterFrameStartedCallback callback.

By default the callback is enabled.

func (*LEDStripV2Bricklet) GetFrameStartedCallbackConfiguration() (enable bool, err error)

Returns the configuration as set by SetFrameStartedCallbackConfiguration().

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 (*LEDStripV2Bricklet) RegisterFrameStartedCallback(func(length uint16)) (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 directly after a new frame render is started. The callback parameter is the number of LEDs in that frame.

You should send the data for the next frame directly after this callback was triggered.

For an explanation of the general approach see SetLEDValues().

Constants

led_strip_v2_bricklet.DeviceIdentifier

This constant is used to identify a LED Strip Bricklet 2.0.

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

led_strip_v2_bricklet.DeviceDisplayName

This constant represents the human readable name of a LED Strip Bricklet 2.0.