Go - Segment Display 4x7 Bricklet

This is the description of the Go API bindings for the Segment Display 4x7 Bricklet. General information and technical specifications for the Segment Display 4x7 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/ipconnection"
    "github.com/Tinkerforge/go-api-bindings/segment_display_4x7_bricklet"
)

const ADDR string = "localhost:4223"
const UID string = "XYZ" // Change XYZ to the UID of your Segment Display 4x7 Bricklet.

var DIGITS = [16]uint8{0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71} // 0~9,A,b,C,d,E,F

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    sd, _ := segment_display_4x7_bricklet.New(UID, &ipcon) // Create device object.

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

    segments := [4]uint8{DIGITS[4], DIGITS[2], DIGITS[2], DIGITS[3]}
    sd.SetSegments(segments, 7, false)

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

API

The Segment Display 4x7 Bricklet API is defined in the package github.com/Tinkerforge/go-api-bindings/segment_display_4x7_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 segment_display_4x7_bricklet.New(uid string, ipcon *IPConnection) (device SegmentDisplay4x7Bricklet, err error)

Creates a new SegmentDisplay4x7Bricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := segment_display_4x7_bricklet.New("YOUR_DEVICE_UID", &ipcon)

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

func (*SegmentDisplay4x7Bricklet) SetSegments(segments [4]uint8, brightness uint8, colon bool) (err error)

The 7-segment display can be set with bitmaps. Every bit controls one segment:

Bit order of one segment

For example to set a "5" you would want to activate segments 0, 2, 3, 5 and 6. This is represented by the number 0b01101101 = 0x6d = 109.

The brightness can be set between 0 (dark) and 7 (bright). The colon parameter turns the colon of the display on or off.

func (*SegmentDisplay4x7Bricklet) GetSegments() (segments [4]uint8, brightness uint8, colon bool, err error)

Returns the segment, brightness and color data as set by SetSegments().

Advanced Functions

func (*SegmentDisplay4x7Bricklet) StartCounter(valueFrom int16, valueTo int16, increment int16, length uint32) (err error)

Starts a counter with the from value that counts to the to value with the each step incremented by increment. The length of the increment is given in ms.

Example: If you set from to 0, to to 100, increment to 1 and length to 1000, a counter that goes from 0 to 100 with one second pause between each increment will be started.

The maximum values for from, to and increment is 9999, the minimum value is -999.

Using a negative increment allows to count backwards.

You can stop the counter at every time by calling SetSegments().

func (*SegmentDisplay4x7Bricklet) GetCounterValue() (value uint16, err error)

Returns the counter value that is currently shown on the display.

If there is no counter running a 0 will be returned.

func (*SegmentDisplay4x7Bricklet) 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 (*SegmentDisplay4x7Bricklet) 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:

  • segment_display_4x7_bricklet.FunctionSetSegments = 1
  • segment_display_4x7_bricklet.FunctionStartCounter = 3
func (*SegmentDisplay4x7Bricklet) 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:

  • segment_display_4x7_bricklet.FunctionSetSegments = 1
  • segment_display_4x7_bricklet.FunctionStartCounter = 3
func (*SegmentDisplay4x7Bricklet) SetResponseExpectedAll(responseExpected bool) (err error)

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

func (*SegmentDisplay4x7Bricklet) 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.

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 (*SegmentDisplay4x7Bricklet) RegisterCounterFinishedCallback(func()) (registrationId uint64)

A callback can be registered for this event with the RegisterCounterFinishedCallback() function. This function returns the ID of the registered callback. An added callback can be removed with the DeregisterCounterFinishedCallback(registrationId uint64) function.

This callback is triggered when the counter (see StartCounter()) is finished.

Constants

segment_display_4x7_bricklet.DeviceIdentifier

This constant is used to identify a Segment Display 4x7 Bricklet.

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

segment_display_4x7_bricklet.DeviceDisplayName

This constant represents the human readable name of a Segment Display 4x7 Bricklet.