Perl - RS232 Bricklet 2.0

This is the description of the Perl API bindings for the RS232 Bricklet 2.0. General information and technical specifications for the RS232 Bricklet 2.0 are summarized in its hardware description.

An installation guide for the Perl API bindings is part of their general description.

Examples

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

Loopback

Download (example_loopback.pl)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
#!/usr/bin/perl

# For this example connect the RX pin to the TX pin on the same Bricklet

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletRS232V2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your RS232 Bricklet 2.0

# Callback subroutine for read callback
sub cb_read # FIXME: is not called for unknown reasons
{
    my ($message) = @_;

    # Assume that the message consists of ASCII characters and convert it
    # from an array of chars to a string
    print "Message: \"" . join('', @{$message}) . "\"\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $rs232 = Tinkerforge::BrickletRS232V2->new(&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 cb_read
$rs232->register_callback($rs232->CALLBACK_READ, 'cb_read');

# Enable read callback
$rs232->enable_read_callback();

# Write "test" string
my @message = split('', 'test');
$rs232->write(\@message);

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

API

Generally, every subroutine of the Perl bindings can report an error as Tinkerforge::Error object via croak(). The object has a get_code() and a get_message() subroutine. There are different error code:

  • Error->ALREADY_CONNECTED = 11
  • Error->NOT_CONNECTED = 12
  • Error->CONNECT_FAILED = 13
  • Error->INVALID_FUNCTION_ID = 21
  • Error->TIMEOUT = 31
  • Error->INVALID_PARAMETER = 41
  • Error->FUNCTION_NOT_SUPPORTED = 42
  • Error->UNKNOWN_ERROR = 43

All methods listed below are thread-safe.

Basic Functions

BrickletRS232V2->new($uid, $ipcon)
Parameters:
  • $uid -- string
  • $ipcon -- IPConnection
Return type:

BrickletRS232V2

Creates an object with the unique device ID $uid:

$rs232_v2 = BrickletRS232V2->new("YOUR_DEVICE_UID", $ipcon);

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

BrickletRS232V2->write(@message)
Parameters:@message -- [char, char, ...]
Return type:int

Writes characters to the RS232 interface. The characters can be binary data, ASCII or similar is not necessary.

The return value is the number of characters that were written.

See set_configuration() for configuration possibilities regarding baud rate, parity and so on.

BrickletRS232V2->read($length)
Parameters:$length -- int
Return type:[char, char, ...]

Returns up to length characters from receive buffer.

Instead of polling with this function, you can also use callbacks. But note that this function will return available data only when the read callback is disabled. See enable_read_callback() and CALLBACK_READ callback.

BrickletRS232V2->set_configuration($baudrate, $parity, $stopbits, $wordlength, $flowcontrol)
Parameters:
  • $baudrate -- int
  • $parity -- int
  • $stopbits -- int
  • $wordlength -- int
  • $flowcontrol -- int
Return type:

undef

Sets the configuration for the RS232 communication. Available options:

  • Baud rate between 100 and 2000000 baud.
  • Parity of none, odd or even.
  • Stop bits can be 1 or 2.
  • Word length of 5 to 8.
  • Flow control can be off, software or hardware.

The default is: 115200 baud, parity none, 1 stop bit, word length 8.

The following constants are available for this function:

  • BrickletRS232V2->PARITY_NONE = 0
  • BrickletRS232V2->PARITY_ODD = 1
  • BrickletRS232V2->PARITY_EVEN = 2
  • BrickletRS232V2->STOPBITS_1 = 1
  • BrickletRS232V2->STOPBITS_2 = 2
  • BrickletRS232V2->WORDLENGTH_5 = 5
  • BrickletRS232V2->WORDLENGTH_6 = 6
  • BrickletRS232V2->WORDLENGTH_7 = 7
  • BrickletRS232V2->WORDLENGTH_8 = 8
  • BrickletRS232V2->FLOWCONTROL_OFF = 0
  • BrickletRS232V2->FLOWCONTROL_SOFTWARE = 1
  • BrickletRS232V2->FLOWCONTROL_HARDWARE = 2
BrickletRS232V2->get_configuration()
Return type:[int, int, int, int, int]

Returns the configuration as set by set_configuration().

The following constants are available for this function:

  • BrickletRS232V2->PARITY_NONE = 0
  • BrickletRS232V2->PARITY_ODD = 1
  • BrickletRS232V2->PARITY_EVEN = 2
  • BrickletRS232V2->STOPBITS_1 = 1
  • BrickletRS232V2->STOPBITS_2 = 2
  • BrickletRS232V2->WORDLENGTH_5 = 5
  • BrickletRS232V2->WORDLENGTH_6 = 6
  • BrickletRS232V2->WORDLENGTH_7 = 7
  • BrickletRS232V2->WORDLENGTH_8 = 8
  • BrickletRS232V2->FLOWCONTROL_OFF = 0
  • BrickletRS232V2->FLOWCONTROL_SOFTWARE = 1
  • BrickletRS232V2->FLOWCONTROL_HARDWARE = 2

The returned array contains the elements baudrate, parity, stopbits, wordlength and flowcontrol.

Advanced Functions

BrickletRS232V2->set_buffer_config($send_buffer_size, $receive_buffer_size)
Parameters:
  • $send_buffer_size -- int
  • $receive_buffer_size -- int
Return type:

undef

Sets the send and receive buffer size in byte. In total the buffers have to be 10240 byte (10kb) in size, the minimum buffer size is 1024 byte (1kb) for each.

The current buffer content is lost if this function is called.

The send buffer holds data that is given by write() and can not be written yet. The receive buffer holds data that is received through RS232 but could not yet be send to the user, either by read() or through CALLBACK_READ callback.

The default configuration is 5120 byte (5kb) per buffer.

BrickletRS232V2->get_buffer_config()
Return type:[int, int]

Returns the buffer configuration as set by set_buffer_config().

The returned array contains the elements send_buffer_size and receive_buffer_size.

BrickletRS232V2->get_buffer_status()
Return type:[int, int]

Returns the currently used bytes for the send and received buffer.

See set_buffer_config() for buffer size configuration.

The returned array contains the elements send_buffer_used and receive_buffer_used.

BrickletRS232V2->get_error_count()
Return type:[int, int]

Returns the current number of overrun and parity errors.

The returned array contains the elements error_count_overrun and error_count_parity.

BrickletRS232V2->get_api_version()
Return type:[int, int, int]

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.

BrickletRS232V2->get_response_expected($function_id)
Parameters:$function_id -- int
Return 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 set_response_expected(). 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 set_response_expected() for the list of function ID constants available for this function.

BrickletRS232V2->set_response_expected($function_id, $response_expected)
Parameters:
  • $function_id -- int
  • $response_expected -- bool
Return type:

undef

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:

  • BrickletRS232V2->FUNCTION_ENABLE_READ_CALLBACK = 3
  • BrickletRS232V2->FUNCTION_DISABLE_READ_CALLBACK = 4
  • BrickletRS232V2->FUNCTION_SET_CONFIGURATION = 6
  • BrickletRS232V2->FUNCTION_SET_BUFFER_CONFIG = 8
  • BrickletRS232V2->FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletRS232V2->FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletRS232V2->FUNCTION_RESET = 243
  • BrickletRS232V2->FUNCTION_WRITE_UID = 248
BrickletRS232V2->set_response_expected_all($response_expected)
Parameters:$response_expected -- bool
Return type:undef

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

BrickletRS232V2->get_spitfp_error_count()
Return type:[int, int, int, int]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned array contains the elements error_count_ack_checksum, error_count_message_checksum, error_count_frame and error_count_overflow.

BrickletRS232V2->set_bootloader_mode($mode)
Parameters:$mode -- int
Return type:int

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletRS232V2->BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletRS232V2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletRS232V2->BOOTLOADER_STATUS_OK = 0
  • BrickletRS232V2->BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletRS232V2->BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletRS232V2->BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletRS232V2->BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletRS232V2->BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletRS232V2->get_bootloader_mode()
Return type:int

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

  • BrickletRS232V2->BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletRS232V2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletRS232V2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletRS232V2->set_write_firmware_pointer($pointer)
Parameters:$pointer -- int
Return type:undef

Sets the firmware pointer for write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletRS232V2->write_firmware(@data)
Parameters:@data -- [int, int, ..61x.., int]
Return type:int

Writes 64 Bytes of firmware at the position as written by set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletRS232V2->set_status_led_config($config)
Parameters:$config -- int
Return type:undef

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletRS232V2->STATUS_LED_CONFIG_OFF = 0
  • BrickletRS232V2->STATUS_LED_CONFIG_ON = 1
  • BrickletRS232V2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletRS232V2->STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletRS232V2->get_status_led_config()
Return type:int

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

  • BrickletRS232V2->STATUS_LED_CONFIG_OFF = 0
  • BrickletRS232V2->STATUS_LED_CONFIG_ON = 1
  • BrickletRS232V2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletRS232V2->STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletRS232V2->get_chip_temperature()
Return type:int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

BrickletRS232V2->reset()
Return type:undef

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

BrickletRS232V2->write_uid($uid)
Parameters:$uid -- int
Return type:undef

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

BrickletRS232V2->read_uid()
Return type:int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

BrickletRS232V2->get_identity()
Return type:[string, string, char, [int, int, int], [int, int, int], int]

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 contains the elements uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletRS232V2->register_callback($id, $callback)
Parameters:
  • $id -- int
  • $callback -- string
Return type:

undef

Registers the given $function name with the given $callback_id.

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

BrickletRS232V2->enable_read_callback()
Return type:undef

Enables the CALLBACK_READ callback.

By default the callback is disabled.

BrickletRS232V2->disable_read_callback()
Return type:undef

Disables the CALLBACK_READ callback.

By default the callback is disabled.

BrickletRS232V2->is_read_callback_enabled()
Return type:bool

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

sub my_callback
{
    print "@_[0]";
}

$rs232_v2->register_callback(BrickletRS232V2->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the IP Connection. In contrast to many other programming languages, variables are not automatically shared between threads in Perl. If you want to share a global variable between a callback function and the rest for your program it has to be marked as :shared. See the documentation of the threads::shared Perl module for more details.

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.

BrickletRS232V2->CALLBACK_READ
Parameters:@message -- [char, char, ...]

This callback is called if new data is available.

To enable this callback, use enable_read_callback().

BrickletRS232V2->CALLBACK_ERROR_COUNT
Parameters:
  • $error_count_overrun -- int
  • $error_count_parity -- int

This callback is called if a new error occurs. It returns the current overrun and parity error count.

Constants

BrickletRS232V2->DEVICE_IDENTIFIER

This constant is used to identify a RS232 Bricklet 2.0.

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

BrickletRS232V2->DEVICE_DISPLAY_NAME

This constant represents the human readable name of a RS232 Bricklet 2.0.