Visual Basic .NET - GPS Bricklet 2.0

This is the description of the Visual Basic .NET API bindings for the GPS Bricklet 2.0. General information and technical specifications for the GPS Bricklet 2.0 are summarized in its hardware description.

An installation guide for the Visual Basic .NET API bindings is part of their general description.

Examples

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

Simple

Download (ExampleSimple.vb)

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Imports System
Imports Tinkerforge

Module ExampleSimple
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223
    Const UID As String = "XYZ" ' Change XYZ to the UID of your GPS Bricklet 2.0

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim gps As New BrickletGPSV2(UID, ipcon) ' Create device object

        ipcon.Connect(HOST, PORT) ' Connect to brickd
        ' Don't use device before ipcon is connected

        ' Get current coordinates
        Dim latitude, longitude As Long
        Dim ns, ew As Char

        gps.GetCoordinates(latitude, ns, longitude, ew)

        Console.WriteLine("Latitude: " + (latitude/1000000.0).ToString() + " °")
        Console.WriteLine("N/S: " + ns)
        Console.WriteLine("Longitude: " + (longitude/1000000.0).ToString() + " °")
        Console.WriteLine("E/W: " + ew)

        Console.WriteLine("Press key to exit")
        Console.ReadLine()
        ipcon.Disconnect()
    End Sub
End Module

Callback

Download (ExampleCallback.vb)

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Imports System
Imports Tinkerforge

Module ExampleCallback
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223
    Const UID As String = "XYZ" ' Change XYZ to the UID of your GPS Bricklet 2.0

    ' Callback subroutine for coordinates callback
    Sub CoordinatesCB(ByVal sender As BrickletGPSV2, ByVal latitude As Long, _
                      ByVal ns As Char, ByVal longitude As Long, ByVal ew As Char)
        Console.WriteLine("Latitude: " + (latitude/1000000.0).ToString() + " °")
        Console.WriteLine("N/S: " + ns)
        Console.WriteLine("Longitude: " + (longitude/1000000.0).ToString() + " °")
        Console.WriteLine("E/W: " + ew)
        Console.WriteLine("")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim gps As New BrickletGPSV2(UID, ipcon) ' Create device object

        ipcon.Connect(HOST, PORT) ' Connect to brickd
        ' Don't use device before ipcon is connected

        ' Register coordinates callback to subroutine CoordinatesCB
        AddHandler gps.CoordinatesCallback, AddressOf CoordinatesCB

        ' Set period for coordinates callback to 1s (1000ms)
        ' Note: The coordinates callback is only called every second
        '       if the coordinates has changed since the last call!
        gps.SetCoordinatesCallbackPeriod(1000)

        Console.WriteLine("Press key to exit")
        Console.ReadLine()
        ipcon.Disconnect()
    End Sub
End Module

API

Since Visual Basic .NET does not support multiple return values directly, we use the ByRef keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

Class BrickletGPSV2(ByVal uid As String, ByVal ipcon As IPConnection)

Creates an object with the unique device ID uid:

Dim gpsV2 As New BrickletGPSV2("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected (see examples above).

Sub BrickletGPSV2.GetCoordinates(ByRef latitude As Long, ByRef ns As Char, ByRef longitude As Long, ByRef ew As Char)

Returns the GPS coordinates. Latitude and longitude are given in the DD.dddddd° format, the value 57123468 means 57.123468°. The parameter ns and ew are the cardinal directions for latitude and longitude. Possible values for ns and ew are 'N', 'S', 'E' and 'W' (north, south, east and west).

This data is only valid if there is currently a fix as indicated by GetStatus().

Sub BrickletGPSV2.GetStatus(ByRef hasFix As Boolean, ByRef satellitesView As Byte)

Returns if a fix is currently available as well as the, the number of satellites that are in view.

There is also a green LED on the Bricklet that indicates the fix status.

Sub BrickletGPSV2.GetAltitude(ByRef altitude As Integer, ByRef geoidalSeparation As Integer)

Returns the current altitude and corresponding geoidal separation.

Both values are given in cm.

This data is only valid if there is currently a fix as indicated by GetStatus().

Sub BrickletGPSV2.GetMotion(ByRef course As Long, ByRef speed As Long)

Returns the current course and speed. Course is given in hundredths degree and speed is given in hundredths km/h. A course of 0° means the Bricklet is traveling north bound and 90° means it is traveling east bound.

Please note that this only returns useful values if an actual movement is present.

This data is only valid if there is currently a fix as indicated by GetStatus().

Sub BrickletGPSV2.GetDateTime(ByRef date As Long, ByRef time As Long)

Returns the current date and time. The date is given in the format ddmmyy and the time is given in the format hhmmss.sss. For example, 140713 means 14.05.13 as date and 195923568 means 19:59:23.568 as time.

Sub BrickletGPSV2.GetSatelliteSystemStatus(ByVal satelliteSystem As Byte, ByRef satelliteNumbers() As Byte, ByRef fix As Byte, ByRef pdop As Integer, ByRef hdop As Integer, ByRef vdop As Integer)

Returns the

  • satellite numbers list (up to 12 items)
  • fix value,
  • PDOP value,
  • HDOP value and
  • VDOP value

for a given satellite system. Currently GPS and GLONASS are supported, Galileo is not yet supported.

The GPS and GLONASS satellites have unique numbers and the satellite list gives the numbers of the satellites that are currently utilized. The number 0 is not a valid satellite number and can be ignored in the list.

The following constants are available for this function:

  • BrickletGPSV2.SATELLITE_SYSTEM_GPS = 0
  • BrickletGPSV2.SATELLITE_SYSTEM_GLONASS = 1
  • BrickletGPSV2.SATELLITE_SYSTEM_GALILEO = 2
  • BrickletGPSV2.FIX_NO_FIX = 1
  • BrickletGPSV2.FIX_2D_FIX = 2
  • BrickletGPSV2.FIX_3D_FIX = 3
Sub BrickletGPSV2.GetSatelliteStatus(ByVal satelliteSystem As Byte, ByVal satelliteNumber As Byte, ByRef elevation As Short, ByRef azimuth As Short, ByRef snr As Short)

Returns the current

  • elevation (0° - 90°),
  • azimuth (0° - 359°) and
  • SNR (0dB - 99dB)

for a given satellite and satellite system.

The satellite number here always goes from 1 to 32. For GLONASS it corresponds to the satellites 65-96.

Galileo is not yet supported.

The following constants are available for this function:

  • BrickletGPSV2.SATELLITE_SYSTEM_GPS = 0
  • BrickletGPSV2.SATELLITE_SYSTEM_GLONASS = 1
  • BrickletGPSV2.SATELLITE_SYSTEM_GALILEO = 2

Advanced Functions

Sub BrickletGPSV2.Restart(ByVal restartType As Byte)

Restarts the GPS Bricklet, the following restart types are available:

Value Description
0 Hot start (use all available data in the NV store)
1 Warm start (don't use ephemeris at restart)
2 Cold start (don't use time, position, almanacs and ephemeris at restart)
3 Factory reset (clear all system/user configurations at restart)

The following constants are available for this function:

  • BrickletGPSV2.RESTART_TYPE_HOT_START = 0
  • BrickletGPSV2.RESTART_TYPE_WARM_START = 1
  • BrickletGPSV2.RESTART_TYPE_COLD_START = 2
  • BrickletGPSV2.RESTART_TYPE_FACTORY_RESET = 3
Sub BrickletGPSV2.SetFixLEDConfig(ByVal config As Byte)

Sets the fix LED configuration. By default the LED shows if the Bricklet got a GPS fix yet. If a fix is established the LED turns on. If there is no fix then the LED is turned off.

You can also turn the LED permanently on/off, show a heartbeat or let it blink in sync with the PPS (pulse per second) output of the GPS module.

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

The following constants are available for this function:

  • BrickletGPSV2.FIX_LED_CONFIG_OFF = 0
  • BrickletGPSV2.FIX_LED_CONFIG_ON = 1
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_FIX = 3
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_PPS = 4
Function BrickletGPSV2.GetFixLEDConfig() As Byte

Returns the configuration as set by SetFixLEDConfig()

The following constants are available for this function:

  • BrickletGPSV2.FIX_LED_CONFIG_OFF = 0
  • BrickletGPSV2.FIX_LED_CONFIG_ON = 1
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_FIX = 3
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_PPS = 4
Sub BrickletGPSV2.SetSBASConfig(ByVal sbasConfig As Byte)

If SBAS is enabled, the position accuracy increases (if SBAS satellites are in view), but the update rate is limited to 5Hz. With SBAS disabled the update rate is increased to 10Hz.

By default SBAS is enabled and the update rate is 5Hz.

The following constants are available for this function:

  • BrickletGPSV2.SBAS_ENABLED = 0
  • BrickletGPSV2.SBAS_DISABLED = 1

New in version 2.0.2 (Plugin).

Function BrickletGPSV2.GetSBASConfig() As Byte

Returns the SBAS configuration as set by SetSBASConfig()

The following constants are available for this function:

  • BrickletGPSV2.SBAS_ENABLED = 0
  • BrickletGPSV2.SBAS_DISABLED = 1

New in version 2.0.2 (Plugin).

Function BrickletGPSV2.GetAPIVersion() As Byte()

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.

Function BrickletGPSV2.GetResponseExpected(ByVal functionId As Byte) As Boolean

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.

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

Sub BrickletGPSV2.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As Boolean)

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:

  • BrickletGPSV2.FUNCTION_RESTART = 6
  • BrickletGPSV2.FUNCTION_SET_FIX_LED_CONFIG = 9
  • BrickletGPSV2.FUNCTION_SET_COORDINATES_CALLBACK_PERIOD = 11
  • BrickletGPSV2.FUNCTION_SET_STATUS_CALLBACK_PERIOD = 13
  • BrickletGPSV2.FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 15
  • BrickletGPSV2.FUNCTION_SET_MOTION_CALLBACK_PERIOD = 17
  • BrickletGPSV2.FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 19
  • BrickletGPSV2.FUNCTION_SET_SBAS_CONFIG = 27
  • BrickletGPSV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletGPSV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletGPSV2.FUNCTION_RESET = 243
  • BrickletGPSV2.FUNCTION_WRITE_UID = 248
Sub BrickletGPSV2.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletGPSV2.GetSPITFPErrorCount(ByRef errorCountAckChecksum As Long, ByRef errorCountMessageChecksum As Long, ByRef errorCountFrame As Long, ByRef errorCountOverflow As Long)

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.

Function BrickletGPSV2.SetBootloaderMode(ByVal mode As Byte) As Byte

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:

  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletGPSV2.BOOTLOADER_STATUS_OK = 0
  • BrickletGPSV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletGPSV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletGPSV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletGPSV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletGPSV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
Function BrickletGPSV2.GetBootloaderMode() As Byte

Returns the current bootloader mode, see SetBootloaderMode().

The following constants are available for this function:

  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
Sub BrickletGPSV2.SetWriteFirmwarePointer(ByVal pointer As Long)

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.

Function BrickletGPSV2.WriteFirmware(ByVal data() As Byte) As Byte

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.

Sub BrickletGPSV2.SetStatusLEDConfig(ByVal config As Byte)

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:

  • BrickletGPSV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletGPSV2.STATUS_LED_CONFIG_ON = 1
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
Function BrickletGPSV2.GetStatusLEDConfig() As Byte

Returns the configuration as set by SetStatusLEDConfig()

The following constants are available for this function:

  • BrickletGPSV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletGPSV2.STATUS_LED_CONFIG_ON = 1
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
Function BrickletGPSV2.GetChipTemperature() As Short

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.

Sub BrickletGPSV2.Reset()

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!

Sub BrickletGPSV2.WriteUID(ByVal uid As Long)

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.

Function BrickletGPSV2.ReadUID() As Long

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

Sub BrickletGPSV2.GetIdentity(ByRef uid As String, ByRef connectedUid As String, ByRef position As Char, ByRef hardwareVersion() As Byte, ByRef firmwareVersion() As Byte, ByRef deviceIdentifier As Integer)

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

Sub BrickletGPSV2.SetCoordinatesCallbackPeriod(ByVal period As Long)

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

The CoordinatesCallback callback is only triggered if the coordinates changed since the last triggering.

The default value is 0.

Function BrickletGPSV2.GetCoordinatesCallbackPeriod() As Long

Returns the period as set by SetCoordinatesCallbackPeriod().

Sub BrickletGPSV2.SetStatusCallbackPeriod(ByVal period As Long)

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

The StatusCallback callback is only triggered if the status changed since the last triggering.

The default value is 0.

Function BrickletGPSV2.GetStatusCallbackPeriod() As Long

Returns the period as set by SetStatusCallbackPeriod().

Sub BrickletGPSV2.SetAltitudeCallbackPeriod(ByVal period As Long)

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

The AltitudeCallback callback is only triggered if the altitude changed since the last triggering.

The default value is 0.

Function BrickletGPSV2.GetAltitudeCallbackPeriod() As Long

Returns the period as set by SetAltitudeCallbackPeriod().

Sub BrickletGPSV2.SetMotionCallbackPeriod(ByVal period As Long)

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

The MotionCallback callback is only triggered if the motion changed since the last triggering.

The default value is 0.

Function BrickletGPSV2.GetMotionCallbackPeriod() As Long

Returns the period as set by SetMotionCallbackPeriod().

Sub BrickletGPSV2.SetDateTimeCallbackPeriod(ByVal period As Long)

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

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

The default value is 0.

Function BrickletGPSV2.GetDateTimeCallbackPeriod() As Long

Returns the period as set by SetDateTimeCallbackPeriod().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a procedure to an callback property of the device object:

Sub MyCallback(ByVal sender As BrickletGPSV2, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler gpsV2.ExampleCallback, AddressOf MyCallback

The available callback property and their type of parameters 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.

Event BrickletGPSV2.PulsePerSecondCallback(ByVal sender As BrickletGPSV2)

This callback is triggered precisely once per second, see PPS.

The precision of two subsequent pulses will be skewed because of the latency in the USB/RS485/Ethernet connection. But in the long run this will be very precise. For example a count of 3600 pulses will take exactly 1 hour.

Event BrickletGPSV2.CoordinatesCallback(ByVal sender As BrickletGPSV2, ByVal latitude As Long, ByVal ns As Char, ByVal longitude As Long, ByVal ew As Char)

This callback is triggered periodically with the period that is set by SetCoordinatesCallbackPeriod(). The parameters are the same as for GetCoordinates().

The CoordinatesCallback callback is only triggered if the coordinates changed since the last triggering and if there is currently a fix as indicated by GetStatus().

Event BrickletGPSV2.StatusCallback(ByVal sender As BrickletGPSV2, ByVal hasFix As Boolean, ByVal satellitesView As Byte)

This callback is triggered periodically with the period that is set by SetStatusCallbackPeriod(). The parameters are the same as for GetStatus().

The StatusCallback callback is only triggered if the status changed since the last triggering.

Event BrickletGPSV2.AltitudeCallback(ByVal sender As BrickletGPSV2, ByVal altitude As Integer, ByVal geoidalSeparation As Integer)

This callback is triggered periodically with the period that is set by SetAltitudeCallbackPeriod(). The parameters are the same as for GetAltitude().

The AltitudeCallback callback is only triggered if the altitude changed since the last triggering and if there is currently a fix as indicated by GetStatus().

Event BrickletGPSV2.MotionCallback(ByVal sender As BrickletGPSV2, ByVal course As Long, ByVal speed As Long)

This callback is triggered periodically with the period that is set by SetMotionCallbackPeriod(). The parameters are the same as for GetMotion().

The MotionCallback callback is only triggered if the motion changed since the last triggering and if there is currently a fix as indicated by GetStatus().

Event BrickletGPSV2.DateTimeCallback(ByVal sender As BrickletGPSV2, ByVal date As Long, ByVal time As Long)

This callback is triggered periodically with the period that is set by SetDateTimeCallbackPeriod(). The parameters are the same as for GetDateTime().

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

Constants

Const BrickletGPSV2.DEVICE_IDENTIFIER

This constant is used to identify a GPS Bricklet 2.0.

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

Const BrickletGPSV2.DEVICE_DISPLAY_NAME

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