PHP - RS232 Bricklet

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

Examples

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

Loopback

Download (ExampleLoopback.php)

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<?php

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

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletRS232.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletRS232;

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

// Convert string to char array with length 60, as needed by write
function stringToCharArray($message)
{
    $chars = str_split($message);

    while (sizeof($chars) < 60)
    {
        array_push($chars, '\0');
    }

    return $chars;
}

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

// Callback function for read callback
function cb_read($message, $length)
{
    $str = charArrayToString($message, $length);
    echo "Message (Length: " . $length . "): \"" . $str . "\"\n";
}

$ipcon = new IPConnection(); // Create IP connection
$rs232 = 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 cb_read
$rs232->registerCallback(BrickletRS232::CALLBACK_READ, 'cb_read');

// Enable read callback
$rs232->enableReadCallback();

// Write "test" string
$message = 'test';
$rs232->write(stringToCharArray($message), strlen($message));

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

API

Functions that return multiple values return them in an associative array.

Basic Functions

class BrickletRS232(string $uid, IPConnection $ipcon)
Parameters:
  • $uid – Type: string
  • $ipcon – Type: IPConnection
Returns:
  • $rs232 – Type: BrickletRS232

Creates an object with the unique device ID $uid:

<?php   $rs232 = new BrickletRS232('YOUR_DEVICE_UID', $ipcon);   ?>

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

int BrickletRS232::write(array $message, int $length)
Parameters:
  • $message – Type: array(string, ...), Length: 60
  • $length – Type: int, Range: [0 to 60]
Returns:
  • $written – Type: int, 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.

array BrickletRS232::read()
Return Array:
  • 'message' – Type: array(string, ...), Length: 60
  • 'length' – Type: int, 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 CALLBACK_READ callback.

void BrickletRS232::setConfiguration(int $baudrate, int $parity, int $stopbits, int $wordlength, int $hardware_flowcontrol, int $software_flowcontrol)
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
  • $hardware_flowcontrol – Type: int, Range: See constants, Default: 0
  • $software_flowcontrol – Type: int, 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 $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
array BrickletRS232::getConfiguration()
Return Array:
  • '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
  • 'hardware_flowcontrol' – Type: int, Range: See constants, Default: 0
  • 'software_flowcontrol' – Type: int, 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 $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
void BrickletRS232::setBreakCondition(int $break_time)
Parameters:
  • $break_time – Type: int, 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).

array BrickletRS232::readFrame()
Return Array:
  • 'message' – Type: array(string, ...), Length: 60
  • 'length' – Type: int, 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

array BrickletRS232::getIdentity()
Return Array:
  • 'uid' – Type: string, Length: up to 8
  • 'connected_uid' – Type: string, Length: up to 8
  • 'position' – Type: string, Range: ['a' to 'h', 'z']
  • 'hardware_version' – Type: array(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]
  • 'firmware_version' – Type: array(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]
  • 'device_identifier' – Type: int, 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

void BrickletRS232::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)
Parameters:
  • $callback_id – Type: int
  • $callback – Type: callable
  • $user_data – Type: mixed

Registers the given $function with the given $callback_id. The optional $user_data will be passed as the last parameter to the function.

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

void BrickletRS232::enableReadCallback()

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

By default the callback is disabled.

void BrickletRS232::disableReadCallback()

Disables the CALLBACK_READ callback.

By default the callback is disabled.

bool BrickletRS232::isReadCallbackEnabled()
Returns:
  • $enabled – Type: bool, Default: FALSE

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

void BrickletRS232::setFrameReadableCallbackConfiguration(int $frame_size)
Parameters:
  • $frame_size – Type: int, Unit: 1 B, Range: [0 to 100], Default: 0

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).

int BrickletRS232::getFrameReadableCallbackConfiguration()
Returns:
  • $frame_size – Type: int, 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 with the registerCallback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

<?php

function myCallback($param)
{
    echo $param . "\n";
}

$rs232->registerCallback(BrickletRS232::CALLBACK_EXAMPLE, 'myCallback');

?>

The available constants with corresponding function signatures 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.

int BrickletRS232::CALLBACK_READ
<?php   void callback(array $message, int $length [, mixed $user_data])   ?>
Callback Parameters:
  • $message – Type: array(string, ...), Length: 60
  • $length – Type: int, Range: [1 to 60]
  • $user_data – Type: mixed

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().

int BrickletRS232::CALLBACK_ERROR
<?php   void callback(int $error [, mixed $user_data])   ?>
Callback Parameters:
  • $error – Type: int, Range: See constants
  • $user_data – Type: mixed

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).

int BrickletRS232::CALLBACK_FRAME_READABLE
<?php   void callback(int $frame_count [, mixed $user_data])   ?>
Callback Parameters:
  • $frame_count – Type: int, Range: [0 to 255]
  • $user_data – Type: mixed

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.

array BrickletRS232::getAPIVersion()
Return Array:
  • $api_version – Type: array(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.

bool BrickletRS232::getResponseExpected(int $function_id)
Parameters:
  • $function_id – Type: int, Range: See constants
Returns:
  • $response_expected – Type: bool

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
void BrickletRS232::setResponseExpected(int $function_id, bool $response_expected)
Parameters:
  • $function_id – Type: int, Range: See constants
  • $response_expected – Type: bool

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 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
void BrickletRS232::setResponseExpectedAll(bool $response_expected)
Parameters:
  • $response_expected – Type: bool

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

Constants

int 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 deviceIdentifier parameter to specify the Brick's or Bricklet's type.

string BrickletRS232::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a RS232 Bricklet.