Software / API Bindings / JavaScript / API Reference and Examples / Bricklets / RS232 Bricklet

JavaScript - RS232 Bricklet¶

This is the description of the JavaScript 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 JavaScript API bindings is part of their general description.

Examples¶

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

Loopback (Node.js)¶

Download (ExampleLoopback.js)

var Tinkerforge = require('tinkerforge');

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

var HOST = 'localhost';
var PORT = 4223;
var UID = 'XYZ'; // Change XYZ to the UID of your RS232 Bricklet

var ipcon = new Tinkerforge.IPConnection(); // Create IP connection
var rs232 = new Tinkerforge.BrickletRS232(UID, ipcon); // Create device object

// Convert string to array of length 60 as needed by write
function stringToCharArray(message) {
    var array = [];
    for(var i = 0; i < message.length; i++) {
        array.push(message[i]);
    }
    for(var i = message.length; i < 60; i++) {
        array.push('\0');
    }
    return array
}

// Assume that the message consists of ASCII characters and
// convert it from an array of chars to a string
function charArrayToString(message, length) {
    return message.slice(0, length).join('');
}

ipcon.connect(HOST, PORT,
    function (error) {
        console.log('Error: ' + error);
    }
); // Connect to brickd
// Don't use device before ipcon is connected

ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
    function (connectReason) {
        // Enable read callback
        rs232.enableReadCallback();

        // Write "test" string
        var message = 'test';
        rs232.write(stringToCharArray(message), message.length);
    }
);

// Register read callback
rs232.on(Tinkerforge.BrickletRS232.CALLBACK_READ,
    // Callback function for read callback
    function (message, length) {
        var str = charArrayToString(message, length);
        console.log('Message (Length: ' + length + '): "' + str + '"');
    }
);

console.log('Press key to exit');
process.stdin.on('data',
    function (data) {
        ipcon.disconnect();
        process.exit(0);
    }
);

Loopback (HTML)¶

Download (ExampleLoopback.html), Test (ExampleLoopback.html)

<!DOCTYPE html>

<!-- For this example connect the RX1 and TX pin to receive the send message -->

<html>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <head>
        <title>Tinkerforge | JavaScript Example</title>
    </head>
    <body>
        <div style="text-align:center;">
            <h1>RS232 Bricklet Loopback Example</h1>
            <p>
                <input value="localhost" id="host" type="text" size="20">:
                <input value="4280" id="port" type="text" size="5">,
                <input value="uid" id="uid" type="text" size="5">
                <input value="Start Example" id="start" type="button" onclick="startExample();">
            </p>
            <p>
                <textarea readonly id="text" cols="80" rows="24" style="resize:none;"
                          >Press "Start Example" to begin ...</textarea>
            </p>
        </div>
        <script src="./Tinkerforge.js" type='text/javascript'></script>
        <script type='text/javascript'>
            // Convert string to array of length 60 as needed by write
            function stringToCharArray(message) {
                var array = [];
                for(var i = 0; i < message.length; i++) {
                    array.push(message[i]);
                }
                for(var i = message.length; i < 60; i++) {
                    array.push('\0');
                }
                return array
            }

            // Assume that the message consists of ASCII characters and
            // convert it from an array of chars to a string
            function charArrayToString(message, len) {
                return message.slice(0, len).join('');
            }

            var ipcon;
            var textArea = document.getElementById("text");
            function startExample() {
                textArea.value = "";
                var HOST = document.getElementById("host").value;
                var PORT = parseInt(document.getElementById("port").value);
                var UID = document.getElementById("uid").value;
                if(ipcon !== undefined) {
                    ipcon.disconnect();
                }
                ipcon = new Tinkerforge.IPConnection(); // Create IP connection
                var rs232 = new Tinkerforge.BrickletRS232(UID, ipcon); // Create device object
                ipcon.connect(HOST, PORT,
                    function(error) {
                        textArea.value += 'Error: ' + error + '\n';
                    }
                ); // Connect to brickd
                // Don't use device before ipcon is connected

                ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
                    function (connectReason) {
                        // Enable read callback
                        rs232.enableReadCallback();

                        // Write "test" string
                        var message = 'test';
                        rs232.write(stringToCharArray(message), message.length);
                    }
                );

                // Register read callback
                rs232.on(Tinkerforge.BrickletRS232.CALLBACK_READ,
                    // Callback function for read callback
                    function (message, len) {
                        var str = charArrayToString(message, len);
                        textArea.value += 'Message (Length: ' + len + '): "' + str + '"\n';
                    }
                );
            }
        </script>
    </body>
</html>

API¶

Generally, every function of the JavaScript bindings can take two optional parameters, returnCallback and errorCallback. These are two user defined callback functions. The returnCallback function is called with the results as arguments, if the function returns its results asynchronously. The errorCallback is called with an error code in case of an error. The error code can be one of the following values:

IPConnection.ERROR_ALREADY_CONNECTED = 11
IPConnection.ERROR_NOT_CONNECTED = 12
IPConnection.ERROR_CONNECT_FAILED = 13
IPConnection.ERROR_INVALID_FUNCTION_ID = 21
IPConnection.ERROR_TIMEOUT = 31
IPConnection.ERROR_INVALID_PARAMETER = 41
IPConnection.ERROR_FUNCTION_NOT_SUPPORTED = 42
IPConnection.ERROR_UNKNOWN_ERROR = 43
IPConnection.ERROR_STREAM_OUT_OF_SYNC = 51
IPConnection.ERROR_NON_ASCII_CHAR_IN_SECRET = 71
IPConnection.ERROR_WRONG_DEVICE_TYPE = 81
IPConnection.ERROR_DEVICE_REPLACED = 82
IPConnection.ERROR_WRONG_RESPONSE_LENGTH = 83
IPConnection.ERROR_INT64_NOT_SUPPORTED = 91

The namespace for the JavaScript bindings is Tinkerforge.*.

Basic Functions¶

new BrickletRS232(uid, ipcon)¶

Parameters:	uid – Type: string ipcon – Type: IPConnection
Returns:	rs232 – Type: BrickletRS232

Creates an object with the unique device ID uid:

var rs232 = new BrickletRS232("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected.

BrickletRS232.write(message, length[, returnCallback][, errorCallback])¶

Parameters:	message – Type: [char, ...], Length: 60 length – Type: int, Range: [0 to 60]
Callback Parameters:	written – Type: int, Range: [0 to 60]
Returns:	undefined

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.

BrickletRS232.read([returnCallback][, errorCallback])¶

Callback Parameters:	message – Type: [char, ...], Length: 60 length – Type: int, Range: [0 to 60]
Returns:	undefined

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 CALLBACK_READ callback.

BrickletRS232.setConfiguration(baudrate, parity, stopbits, wordlength, hardwareFlowcontrol, softwareFlowcontrol[, returnCallback][, errorCallback])¶

Parameters:	baudrate – Type: int, Range: See constants, Default: 11 parity – Type: int, Range: See constants, Default: 0 stopbits – Type: int, Range: See constants, Default: 1 wordlength – Type: int, Range: See constants, Default: 8 hardwareFlowcontrol – Type: int, Range: See constants, Default: 0 softwareFlowcontrol – Type: int, Range: See constants, Default: 0
Callback Parameters:	undefined
Returns:	undefined

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 hardware_flowcontrol:

BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1

For software_flowcontrol:

BrickletRS232.SOFTWARE_FLOWCONTROL_OFF = 0
BrickletRS232.SOFTWARE_FLOWCONTROL_ON = 1

BrickletRS232.getConfiguration([returnCallback][, errorCallback])¶

Callback Parameters:	baudrate – Type: int, Range: See constants, Default: 11 parity – Type: int, Range: See constants, Default: 0 stopbits – Type: int, Range: See constants, Default: 1 wordlength – Type: int, Range: See constants, Default: 8 hardwareFlowcontrol – Type: int, Range: See constants, Default: 0 softwareFlowcontrol – Type: int, Range: See constants, Default: 0
Returns:	undefined

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 hardware_flowcontrol:

BrickletRS232.HARDWARE_FLOWCONTROL_OFF = 0
BrickletRS232.HARDWARE_FLOWCONTROL_ON = 1

For software_flowcontrol:

BrickletRS232.SOFTWARE_FLOWCONTROL_OFF = 0
BrickletRS232.SOFTWARE_FLOWCONTROL_ON = 1

BrickletRS232.setBreakCondition(breakTime[, returnCallback][, errorCallback])¶

Parameters:	breakTime – Type: int, Unit: 1 ms, Range: [0 to 2¹⁶ - 1]
Callback Parameters:	undefined
Returns:	undefined

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).

BrickletRS232.readFrame([returnCallback][, errorCallback])¶

Callback Parameters:	message – Type: [char, ...], Length: 60 length – Type: int, Range: [0 to 60]
Returns:	undefined

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¶

BrickletRS232.getIdentity([returnCallback][, errorCallback])¶

Callback Parameters:

Callback Parameters:	uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: char, Range: ['a' to 'h', 'z'] hardwareVersion – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] firmwareVersion – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] deviceIdentifier – Type: int, Range: [0 to 2¹⁶ - 1]
Returns:	undefined

uid – Type: string, Length: up to 8
connectedUid – Type: string, Length: up to 8
position – Type: char, Range: ['a' to 'h', 'z']
hardwareVersion – Type: [int, ...], Length: 3

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

firmwareVersion – Type: [int, ...], Length: 3

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

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

Returns:

undefined

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¶

BrickletRS232.on(callback_id, function[, errorCallback])¶

Parameters:	callback_id – Type: int function – Type: function
Returns:	undefined

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletRS232.enableReadCallback([returnCallback][, errorCallback])¶

Callback Parameters:	undefined
Returns:	undefined

Enables the CALLBACK_READ callback. This will disable the CALLBACK_FRAME_READABLE callback.

By default the callback is disabled.

BrickletRS232.disableReadCallback([returnCallback][, errorCallback])¶

Callback Parameters:	undefined
Returns:	undefined

Disables the CALLBACK_READ callback.

By default the callback is disabled.

BrickletRS232.isReadCallbackEnabled([returnCallback][, errorCallback])¶

Callback Parameters:	enabled – Type: boolean, Default: false
Returns:	undefined

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

BrickletRS232.setFrameReadableCallbackConfiguration(frameSize[, returnCallback][, errorCallback])¶

Parameters:	frameSize – Type: int, Unit: 1 B, Range: [0 to 100], Default: 0
Callback Parameters:	undefined
Returns:	undefined

Configures the CALLBACK_FRAME_READABLE 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 CALLBACK_READ callback.

By default the callback is disabled.

New in version 2.0.4 (Plugin).

BrickletRS232.getFrameReadableCallbackConfiguration([returnCallback][, errorCallback])¶

Callback Parameters:	frameSize – Type: int, Unit: 1 B, Range: [0 to 100], Default: 0
Returns:	undefined

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 with the on() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

rs232.on(BrickletRS232.CALLBACK_EXAMPLE,
    function (param) {
        console.log(param);
    }
);

The available constants with inherent number and 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.

BrickletRS232.CALLBACK_READ¶

Callback Parameters:	message – Type: [char, ...], Length: 60 length – Type: int, 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().

BrickletRS232.CALLBACK_ERROR¶

Callback Parameters:	error – Type: int, 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).

BrickletRS232.CALLBACK_FRAME_READABLE¶

Callback Parameters:	frameCount – Type: int, 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.

BrickletRS232.getAPIVersion()¶

Returns:	apiVersion – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, 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.

BrickletRS232.getResponseExpected(functionId[, errorCallback])¶

Parameters:	functionId – Type: int, 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 function_id:

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

BrickletRS232.setResponseExpected(functionId, responseExpected[, errorCallback])¶

Parameters:	functionId – Type: int, Range: See constants responseExpected – Type: boolean
Returns:	undefined

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 function_id:

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

BrickletRS232.setResponseExpectedAll(responseExpected)¶

Parameters:	responseExpected – Type: boolean
Returns:	undefined

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

Constants¶

BrickletRS232.DEVICE_IDENTIFIER¶

This constant is used to identify a RS232 Bricklet.

The getIdentity() function and the IPConnection.CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

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