Visual Basic .NET - RS232 Bricklet – Tinkerforge

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# Visual Basic .NET - RS232 Bricklet

Note

This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.

This is the description of the Visual Basic .NET API bindings for the RS232 Bricklet. General information and technical specifications for the RS232 Bricklet 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).

### Loopback

Download (ExampleLoopback.vb)

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    Imports Tinkerforge
    Imports System

    ' In this program we connect RX to TX and to receive
    ' the messages that we are sending

    Module ExampleCallback
        Const HOST As String = "localhost"
        Const PORT As Integer = 4223
        Const UID As String = "XYZ" ' Change to your UID

        Function StringToCharArray(ByVal message As string) As Char()
            Dim arr As Char() = message.ToCharArray()
            ReDim Preserve arr(60)

            Return arr
        End Function

        ' Callback function for read callback
        Sub ReadCB(ByVal sender As BrickletRS232, ByVal message As Char(), ByVal length As Byte)
            Dim str as String = new String(message)
            System.Console.WriteLine("message (length: {0}): '{1}'", length, str)
        End Sub

        Sub Main()
            Dim ipcon As New IPConnection() ' Create IP connection
            Dim rs232 As New BrickletRS232(UID, ipcon) ' Create device object

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

            ' Register read callback to function ReadCB
            AddHandler rs232.ReadCallback, AddressOf ReadCB
            rs232.EnableCallback()

            rs232.Write(StringToCharArray("test"), 4)

            System.Console.WriteLine("Press key to exit")
            System.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 `BrickletRS232`(ByVal uid As String, ByVal ipcon As IPConnection)

  Creates an object with the unique device ID `uid`:

      Dim rs232 As New BrickletRS232("YOUR_DEVICE_UID", ipcon)

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

Function `BrickletRS232.``Write`(ByVal message() As Char, ByVal length As Byte) As Byte

  Writes a string of up to 60 characters to the RS232 interface. The string can be binary data, ASCII or similar is not necessary.

  The length of the string has to be given as an additional parameter.

  The return value is the number of bytes that could be written.

  See `SetConfigurations()` for configuration possibilities regarding baudrate, parity and so on.

Sub `BrickletRS232.``Read`(ByRef message() As Char, ByRef length As Byte)

  Returns the currently buffered message. The maximum length of message is 60. If the length is given as 0, there was no new data available.

  Instead of polling with this function, you can also use callbacks. See `EnableCallback()` and `ReadCallback`.

Sub `BrickletRS232.``SetConfiguration`(ByVal baudrate As Byte, ByVal parity As Byte, ByVal stopbits As Byte, ByVal wordlength As Byte, ByVal hardwareFlowcontrol As Byte, ByVal softwareFlowcontrol As Byte)

  Sets the configuration for the RS232 communication. Available options:

  - Baudrate between 300 and 230400 baud.
  - Parity of none, odd, even or forced parity.
  - Stopbits can be 1 or 2.
  - Word length of 5 to 8.
  - Hard-/Software flow control can each be on or off.

  The default is: 115200 baud, parity none, 1 stop bit, word length 8, hard-/software flow control off.

  The following constants are available for this function:

  - BrickletRS232.BAUDRATE_300 = 0
  - BrickletRS232.BAUDRATE_600 = 1
  - BrickletRS232.BAUDRATE_1200 = 2
  - BrickletRS232.BAUDRATE_2400 = 3
  - BrickletRS232.BAUDRATE_4800 = 4
  - BrickletRS232.BAUDRATE_9600 = 5
  - BrickletRS232.BAUDRATE_14400 = 6
  - BrickletRS232.BAUDRATE_28800 = 7
  - BrickletRS232.BAUDRATE_38400 = 8
  - BrickletRS232.BAUDRATE_57600 = 9
  - BrickletRS232.BAUDRATE_115200 = 10
  - BrickletRS232.BAUDRATE_230400 = 11
  - BrickletRS232.PARITY_NONE = 0
  - BrickletRS232.PARITY_ODD = 1
  - BrickletRS232.PARITY_EVEN = 2
  - BrickletRS232.PARITY_FORCED_PARITY_1 = 3
  - BrickletRS232.PARITY_FORCED_PARITY_0 = 4
  - BrickletRS232.STOPBITS_1 = 1
  - BrickletRS232.STOPBITS_2 = 2
  - BrickletRS232.WORDLENGTH_5 = 5
  - BrickletRS232.WORDLENGTH_6 = 6
  - BrickletRS232.WORDLENGTH_7 = 7
  - BrickletRS232.WORDLENGTH_8 = 8
  - BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
  - BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1
  - BrickletRS232.SOFTWARE_FLOWCONTROL_OFF = 0
  - BrickletRS232.SOFTWARE_FLOWCONTROL_ON = 1

Sub `BrickletRS232.``GetConfiguration`(ByRef baudrate As Byte, ByRef parity As Byte, ByRef stopbits As Byte, ByRef wordlength As Byte, ByRef hardwareFlowcontrol As Byte, ByRef softwareFlowcontrol As Byte)

  Returns the configuration as set by `SetConfiguration()`.

  The following constants are available for this function:

  - BrickletRS232.BAUDRATE_300 = 0
  - BrickletRS232.BAUDRATE_600 = 1
  - BrickletRS232.BAUDRATE_1200 = 2
  - BrickletRS232.BAUDRATE_2400 = 3
  - BrickletRS232.BAUDRATE_4800 = 4
  - BrickletRS232.BAUDRATE_9600 = 5
  - BrickletRS232.BAUDRATE_14400 = 6
  - BrickletRS232.BAUDRATE_28800 = 7
  - BrickletRS232.BAUDRATE_38400 = 8
  - BrickletRS232.BAUDRATE_57600 = 9
  - BrickletRS232.BAUDRATE_115200 = 10
  - BrickletRS232.BAUDRATE_230400 = 11
  - BrickletRS232.PARITY_NONE = 0
  - BrickletRS232.PARITY_ODD = 1
  - BrickletRS232.PARITY_EVEN = 2
  - BrickletRS232.PARITY_FORCED_PARITY_1 = 3
  - BrickletRS232.PARITY_FORCED_PARITY_0 = 4
  - BrickletRS232.STOPBITS_1 = 1
  - BrickletRS232.STOPBITS_2 = 2
  - BrickletRS232.WORDLENGTH_5 = 5
  - BrickletRS232.WORDLENGTH_6 = 6
  - BrickletRS232.WORDLENGTH_7 = 7
  - BrickletRS232.WORDLENGTH_8 = 8
  - BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
  - BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1
  - BrickletRS232.SOFTWARE_FLOWCONTROL_OFF = 0
  - BrickletRS232.SOFTWARE_FLOWCONTROL_ON = 1

### Advanced Functions

Function `BrickletRS232.``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 `BrickletRS232.``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 `BrickletRS232.``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 and callbacks it is always disabled.

  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:

  - BrickletRS232.FUNCTION_ENABLE_CALLBACK = 3
  - BrickletRS232.FUNCTION_DISABLE_CALLBACK = 4
  - BrickletRS232.FUNCTION_SET_CONFIGURATION = 6

Sub `BrickletRS232.``SetResponseExpectedAll`(ByVal responseExpected As Boolean)

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

Sub `BrickletRS232.``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 `BrickletRS232.``EnableCallback`()

  Enables the `ReadCallback`.

  By default the callback is disabled.

Sub `BrickletRS232.``DisableCallback`()

  Disables the `ReadCallback`.

  By default the callback is disabled.

Function `BrickletRS232.``IsCallbackEnabled`() As Boolean

  Returns true if the `ReadCallback` is enabled, false otherwise.

### 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 Callback(ByVal sender As BrickletRS232, ByVal value As Short)
>         Console.WriteLine("Value: {0}", value)
>     End Sub

>     AddHandler rs232.Example, AddressOf Callback

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 `BrickletRS232.``ReadCallback`(ByVal sender As BrickletRS232, ByVal message() As Char, ByVal length As Byte)

  This callback is called if new data is available. The message has a maximum size of 60 characters. The actual length of the message is given in addition.

  To enable this callback, use `EnableCallback()`.

### Constants

Const `BrickletRS232.``DEVICE_IDENTIFIER`

  This constant is used to identify a RS232 Bricklet.

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

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