Software / API Bindings / Visual Basic .NET / API Reference and Examples / Bricklets / RS232 Bricklet

Visual Basic .NET - RS232 Bricklet¶

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)

Imports System
Imports Tinkerforge

' For this example connect the RX1 and TX pin to receive the send message

Module ExampleLoopback
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223
    Const UID As String = "XYZ" ' Change XYZ to the UID of your RS232 Bricklet

    ' Convert message to array of length 60 as needed by write
    Function StringToCharArray(ByVal message As String) As Char()
        Dim chars As Char() = message.ToCharArray()
        ReDim Preserve chars(60)
        Return chars
    End Function

    ' Assume that the message consists of ASCII characters and
    ' convert it from an array of chars to a string
    Function CharArrayToString(ByVal message As Char(), ByVal length As Byte) As String
        Return new String(message, 0, length)
    End Function

    ' Callback subroutine for read callback
    Sub ReadCB(ByVal sender As BrickletRS232, ByVal message As Char(), _
               ByVal length As Byte)
        Dim ascii as String = CharArrayToString(message, length)
        Console.WriteLine("Message (Length: {0}): ""{1}""", length, ascii)
    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 subroutine ReadCB
        AddHandler rs232.ReadCallback, AddressOf ReadCB

        ' Enable read callback
        rs232.EnableReadCallback()

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

        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 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.

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

Parameters:	message – Type: Char Array, Length: 60 length – Type: Byte, Range: [0 to 60]
Returns:	written – Type: Byte, Range: [0 to 60]

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 SetConfiguration() for configuration possibilities regarding baudrate, parity and so on.

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

Output Parameters:	message – Type: Char Array, Length: 60 length – Type: Byte, Range: [0 to 60]

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

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

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)¶

Parameters:	baudrate – Type: Byte, Range: See constants, Default: 11 parity – Type: Byte, Range: See constants, Default: 0 stopbits – Type: Byte, Range: See constants, Default: 1 wordlength – Type: Byte, Range: See constants, Default: 8 hardwareFlowcontrol – Type: Byte, Range: See constants, Default: 0 softwareFlowcontrol – Type: Byte, Range: See constants, Default: 0

Sets the configuration for the RS232 communication.

Hard-/Software flow control can either be on or off but not both simultaneously on.

The following constants are available for this function:

For baudrate:

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_19200 = 7
BrickletRS232.BAUDRATE_28800 = 8
BrickletRS232.BAUDRATE_38400 = 9
BrickletRS232.BAUDRATE_57600 = 10
BrickletRS232.BAUDRATE_115200 = 11
BrickletRS232.BAUDRATE_230400 = 12

For parity:

BrickletRS232.PARITY_NONE = 0
BrickletRS232.PARITY_ODD = 1
BrickletRS232.PARITY_EVEN = 2
BrickletRS232.PARITY_FORCED_PARITY_1 = 3
BrickletRS232.PARITY_FORCED_PARITY_0 = 4

For stopbits:

BrickletRS232.STOPBITS_1 = 1
BrickletRS232.STOPBITS_2 = 2

For wordlength:

BrickletRS232.WORDLENGTH_5 = 5
BrickletRS232.WORDLENGTH_6 = 6
BrickletRS232.WORDLENGTH_7 = 7
BrickletRS232.WORDLENGTH_8 = 8

For hardwareFlowcontrol:

BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1

For softwareFlowcontrol:

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)¶

Output Parameters:	baudrate – Type: Byte, Range: See constants, Default: 11 parity – Type: Byte, Range: See constants, Default: 0 stopbits – Type: Byte, Range: See constants, Default: 1 wordlength – Type: Byte, Range: See constants, Default: 8 hardwareFlowcontrol – Type: Byte, Range: See constants, Default: 0 softwareFlowcontrol – Type: Byte, Range: See constants, Default: 0

Returns the configuration as set by SetConfiguration().

The following constants are available for this function:

For baudrate:

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_19200 = 7
BrickletRS232.BAUDRATE_28800 = 8
BrickletRS232.BAUDRATE_38400 = 9
BrickletRS232.BAUDRATE_57600 = 10
BrickletRS232.BAUDRATE_115200 = 11
BrickletRS232.BAUDRATE_230400 = 12

For parity:

BrickletRS232.PARITY_NONE = 0
BrickletRS232.PARITY_ODD = 1
BrickletRS232.PARITY_EVEN = 2
BrickletRS232.PARITY_FORCED_PARITY_1 = 3
BrickletRS232.PARITY_FORCED_PARITY_0 = 4

For stopbits:

BrickletRS232.STOPBITS_1 = 1
BrickletRS232.STOPBITS_2 = 2

For wordlength:

BrickletRS232.WORDLENGTH_5 = 5
BrickletRS232.WORDLENGTH_6 = 6
BrickletRS232.WORDLENGTH_7 = 7
BrickletRS232.WORDLENGTH_8 = 8

For hardwareFlowcontrol:

BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1

For softwareFlowcontrol:

BrickletRS232.SOFTWARE_FLOWCONTROL_OFF = 0
BrickletRS232.SOFTWARE_FLOWCONTROL_ON = 1

Sub BrickletRS232.SetBreakCondition(ByVal breakTime As Integer)¶

Parameters:	breakTime – Type: Integer, Unit: 1 ms, Range: [0 to 2¹⁶ - 1]

Sets a break condition (the TX output is forced to a logic 0 state). The parameter sets the hold-time of the break condition.

New in version 2.0.2 (Plugin).

Sub BrickletRS232.ReadFrame(ByRef message() As Char, ByRef length As Byte)¶

Output Parameters:	message – Type: Char Array, Length: 60 length – Type: Byte, Range: [0 to 60]

Returns up to one frame of bytes from the read buffer. The frame size is configured with SetFrameReadableCallbackConfiguration(). If the returned length is 0, no new data was available.

New in version 2.0.4 (Plugin).

Advanced Functions¶

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)¶

Output Parameters:

Output Parameters:	uid – Type: String, Length: up to 8 connectedUid – Type: String, Length: up to 8 position – Type: Char, Range: ["a"C to "h"C, "z"C] hardwareVersion – Type: Byte Array, Length: 3 0: major – Type: Byte, Range: [0 to 255] 1: minor – Type: Byte, Range: [0 to 255] 2: revision – Type: Byte, Range: [0 to 255] firmwareVersion – Type: Byte Array, Length: 3 0: major – Type: Byte, Range: [0 to 255] 1: minor – Type: Byte, Range: [0 to 255] 2: revision – Type: Byte, Range: [0 to 255] deviceIdentifier – Type: Integer, Range: [0 to 2¹⁶ - 1]

uid – Type: String, Length: up to 8
connectedUid – Type: String, Length: up to 8
position – Type: Char, Range: ["a"C to "h"C, "z"C]
hardwareVersion – Type: Byte Array, Length: 3

0: major – Type: Byte, Range: [0 to 255]
1: minor – Type: Byte, Range: [0 to 255]
2: revision – Type: Byte, Range: [0 to 255]

firmwareVersion – Type: Byte Array, Length: 3

0: major – Type: Byte, Range: [0 to 255]
1: minor – Type: Byte, Range: [0 to 255]
2: revision – Type: Byte, Range: [0 to 255]

deviceIdentifier – Type: Integer, Range: [0 to 2¹⁶ - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

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.EnableReadCallback()¶

Enables the ReadCallback callback. This will disable the FrameReadableCallback callback.

By default the callback is disabled.

Sub BrickletRS232.DisableReadCallback()¶

Disables the ReadCallback callback.

By default the callback is disabled.

Function BrickletRS232.IsReadCallbackEnabled() As Boolean¶

Returns:	enabled – Type: Boolean, Default: false

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

Sub BrickletRS232.SetFrameReadableCallbackConfiguration(ByVal frameSize As Byte)¶

Parameters:	frameSize – Type: Byte, Unit: 1 B, Range: [0 to 100], Default: 0

Configures the FrameReadableCallback callback. The frame size is the number of bytes, that have to be readable to trigger the callback. A frame size of 0 disables the callback. A frame size greater than 0 enables the callback and disables the ReadCallback callback.

By default the callback is disabled.

New in version 2.0.4 (Plugin).

Function BrickletRS232.GetFrameReadableCallbackConfiguration() As Byte¶

Returns:	frameSize – Type: Byte, Unit: 1 B, Range: [0 to 100], Default: 0

Returns the callback configuration as set by SetFrameReadableCallbackConfiguration().

New in version 2.0.4 (Plugin).

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

AddHandler rs232.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 BrickletRS232.ReadCallback(ByVal sender As BrickletRS232, ByVal message() As Char, ByVal length As Byte)¶

Callback Parameters:	sender – Type: BrickletRS232 message – Type: Char Array, Length: 60 length – Type: Byte, Range: [1 to 60]

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 EnableReadCallback().

Event BrickletRS232.ErrorCallback(ByVal sender As BrickletRS232, ByVal error As Byte)¶

Callback Parameters:	sender – Type: BrickletRS232 error – Type: Byte, Range: See constants

This callback is called if an error occurs. Possible errors are overrun, parity or framing error.

The following constants are available for this function:

For error:

BrickletRS232.ERROR_OVERRUN = 1
BrickletRS232.ERROR_PARITY = 2
BrickletRS232.ERROR_FRAMING = 4

New in version 2.0.1 (Plugin).

Event BrickletRS232.FrameReadableCallback(ByVal sender As BrickletRS232, ByVal frameCount As Byte)¶

Callback Parameters:	sender – Type: BrickletRS232 frameCount – Type: Byte, Range: [0 to 255]

This callback is called if at least one frame of data is readable. The frame size is configured with SetFrameReadableCallbackConfiguration(). The frame count parameter is the number of frames that can be read. This callback is triggered only once until Read() or ReadFrame() is called. This means, that if you have configured a frame size of X bytes, you can read exactly X bytes using the ReadFrame() function, every time the callback triggers without checking the frame count parameter.

New in version 2.0.4 (Plugin).

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

Function BrickletRS232.GetAPIVersion() As Byte()¶

Output Parameters:	apiVersion – Type: Byte Array, Length: 3 0: major – Type: Byte, Range: [0 to 255] 1: minor – Type: Byte, Range: [0 to 255] 2: revision – Type: Byte, Range: [0 to 255]

Returns the version of the API definition 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¶

Parameters:	functionId – Type: Byte, Range: See constants
Returns:	responseExpected – Type: 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

BrickletRS232.FUNCTION_ENABLE_READ_CALLBACK = 3
BrickletRS232.FUNCTION_DISABLE_READ_CALLBACK = 4
BrickletRS232.FUNCTION_SET_CONFIGURATION = 6
BrickletRS232.FUNCTION_SET_BREAK_CONDITION = 10
BrickletRS232.FUNCTION_SET_FRAME_READABLE_CALLBACK_CONFIGURATION = 11

Sub BrickletRS232.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As Boolean)¶

Parameters:	functionId – Type: Byte, Range: See constants responseExpected – Type: 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.

The following constants are available for this function:

For functionId:

BrickletRS232.FUNCTION_ENABLE_READ_CALLBACK = 3
BrickletRS232.FUNCTION_DISABLE_READ_CALLBACK = 4
BrickletRS232.FUNCTION_SET_CONFIGURATION = 6
BrickletRS232.FUNCTION_SET_BREAK_CONDITION = 10
BrickletRS232.FUNCTION_SET_FRAME_READABLE_CALLBACK_CONFIGURATION = 11

Sub BrickletRS232.SetResponseExpectedAll(ByVal responseExpected As Boolean)¶

Parameters:	responseExpected – Type: Boolean

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

Constants¶

Const BrickletRS232.DEVICE_IDENTIFIER¶

This constant is used to identify a RS232 Bricklet.

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

Const BrickletRS232.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a RS232 Bricklet.