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)

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 (see examples above).

int BrickletRS232::write(array $message, int $length)

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()

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 enableReadCallback() and CALLBACK_READ callback.

The returned array has the keys message and length.

void BrickletRS232::setConfiguration(int $baudrate, int $parity, int $stopbits, int $wordlength, int $hardware_flowcontrol, int $software_flowcontrol)

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 either be on or off but not both simultaneously on.

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_19200 = 7
  • BrickletRS232::BAUDRATE_28800 = 8
  • BrickletRS232::BAUDRATE_38400 = 9
  • BrickletRS232::BAUDRATE_57600 = 10
  • BrickletRS232::BAUDRATE_115200 = 11
  • BrickletRS232::BAUDRATE_230400 = 12
  • 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
array BrickletRS232::getConfiguration()

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

The returned array has the keys baudrate, parity, stopbits, wordlength, hardware_flowcontrol and software_flowcontrol.

void BrickletRS232::setBreakCondition(int $break_time)

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

New in version 2.0.2 (Plugin).

Advanced Functions

array BrickletRS232::getAPIVersion()

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.

bool BrickletRS232::getResponseExpected(int $function_id)

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.

void BrickletRS232::setResponseExpected(int $function_id, bool $response_expected)

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:

  • BrickletRS232::FUNCTION_ENABLE_READ_CALLBACK = 3
  • BrickletRS232::FUNCTION_DISABLE_READ_CALLBACK = 4
  • BrickletRS232::FUNCTION_SET_CONFIGURATION = 6
  • BrickletRS232::FUNCTION_SET_BREAK_CONDITION = 10
void BrickletRS232::setResponseExpectedAll(bool $response_expected)

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

array BrickletRS232::getIdentity()

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.

The returned array has the keys uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

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

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.

By default the callback is disabled.

void BrickletRS232::disableReadCallback()

Disables the CALLBACK_READ callback.

By default the callback is disabled.

bool BrickletRS232::isReadCallbackEnabled()

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

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])   ?>

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])   ?>

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

The following constants are available for this function:

  • BrickletRS232::ERROR_OVERRUN = 1
  • BrickletRS232::ERROR_PARITY = 2
  • BrickletRS232::ERROR_FRAMING = 4

New in version 2.0.1 (Plugin).

Constants

int BrickletRS232::DEVICE_IDENTIFIER

This constant is used to identify a RS232 Bricklet.

The getIdentity() function and the 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.