Python - RS232 Bricklet 2.0¶

Loopback¶

Download (example_loopback.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

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

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your RS232 Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_rs232_v2 import BrickletRS232V2

# Callback function for read callback
def cb_read(message):
    # Assume that the message consists of ASCII characters and convert it
    # from an array of chars to a string
    print('Message: "' + ''.join(message) + '"')

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    rs232 = BrickletRS232V2(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.register_callback(rs232.CALLBACK_READ, cb_read)

    # Enable read callback
    rs232.enable_read_callback()

    # Write "test" string
    rs232.write(list('test'))

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

Basic Functions¶

BrickletRS232V2(uid, ipcon)¶

Parameters:	uid – Type: str ipcon – Type: IPConnection
Returns:	rs232_v2 – Type: BrickletRS232V2

Creates an object with the unique device ID uid:

rs232_v2 = BrickletRS232V2("YOUR_DEVICE_UID", ipcon)

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

BrickletRS232V2.write(message)¶

Parameters:	message – Type: [chr, ...], Length: variable
Returns:	message_written – Type: int, Range: [0 to 216 - 1]

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 – Type: int, Range: [0 to 216 - 1]
Returns:	message – Type: [chr, ...], Length: variable

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 – Type: int, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200 parity – Type: int, Range: See constants, Default: 0 stopbits – Type: int, Range: See constants, Default: 1 wordlength – Type: int, Range: See constants, Default: 8 flowcontrol – Type: int, Range: See constants, Default: 0
Returns:	None

Sets the configuration for the RS232 communication.

The following constants are available for this function:

For parity:

• BrickletRS232V2.PARITY_NONE = 0
• BrickletRS232V2.PARITY_ODD = 1
• BrickletRS232V2.PARITY_EVEN = 2

For stopbits:

• BrickletRS232V2.STOPBITS_1 = 1
• BrickletRS232V2.STOPBITS_2 = 2

For wordlength:

• BrickletRS232V2.WORDLENGTH_5 = 5
• BrickletRS232V2.WORDLENGTH_6 = 6
• BrickletRS232V2.WORDLENGTH_7 = 7
• BrickletRS232V2.WORDLENGTH_8 = 8

For flowcontrol:

• BrickletRS232V2.FLOWCONTROL_OFF = 0
• BrickletRS232V2.FLOWCONTROL_SOFTWARE = 1
• BrickletRS232V2.FLOWCONTROL_HARDWARE = 2

BrickletRS232V2.get_configuration()¶

Return Object:	baudrate – Type: int, Unit: 1 Bd, Range: [100 to 2000000], Default: 115200 parity – Type: int, Range: See constants, Default: 0 stopbits – Type: int, Range: See constants, Default: 1 wordlength – Type: int, Range: See constants, Default: 8 flowcontrol – Type: int, Range: See constants, Default: 0

Returns the configuration as set by set_configuration().

The following constants are available for this function:

For parity:

• BrickletRS232V2.PARITY_NONE = 0
• BrickletRS232V2.PARITY_ODD = 1
• BrickletRS232V2.PARITY_EVEN = 2

For stopbits:

• BrickletRS232V2.STOPBITS_1 = 1
• BrickletRS232V2.STOPBITS_2 = 2

For wordlength:

• BrickletRS232V2.WORDLENGTH_5 = 5
• BrickletRS232V2.WORDLENGTH_6 = 6
• BrickletRS232V2.WORDLENGTH_7 = 7
• BrickletRS232V2.WORDLENGTH_8 = 8

For flowcontrol:

• BrickletRS232V2.FLOWCONTROL_OFF = 0
• BrickletRS232V2.FLOWCONTROL_SOFTWARE = 1
• BrickletRS232V2.FLOWCONTROL_HARDWARE = 2

Advanced Functions¶

BrickletRS232V2.set_buffer_config(send_buffer_size, receive_buffer_size)¶

Parameters:	send_buffer_size – Type: int, Unit: 1 B, Range: [210 to 9216], Default: 5120 receive_buffer_size – Type: int, Unit: 1 B, Range: [210 to 9216], Default: 5120
Returns:	None

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

BrickletRS232V2.get_buffer_config()¶

Return Object:	send_buffer_size – Type: int, Unit: 1 B, Range: [210 to 9216], Default: 5120 receive_buffer_size – Type: int, Unit: 1 B, Range: [210 to 9216], Default: 5120

Returns the buffer configuration as set by set_buffer_config().

BrickletRS232V2.get_buffer_status()¶

Return Object:	send_buffer_used – Type: int, Unit: 1 B, Range: [0 to 9216] receive_buffer_used – Type: int, Unit: 1 B, Range: [0 to 9216]

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

See set_buffer_config() for buffer size configuration.

BrickletRS232V2.get_error_count()¶

Return Object:	error_count_overrun – Type: int, Range: [0 to 232 - 1] error_count_parity – Type: int, Range: [0 to 232 - 1]

Returns the current number of overrun and parity errors.

BrickletRS232V2.get_spitfp_error_count()¶

Return Object:	error_count_ack_checksum – Type: int, Range: [0 to 232 - 1] error_count_message_checksum – Type: int, Range: [0 to 232 - 1] error_count_frame – Type: int, Range: [0 to 232 - 1] error_count_overflow – Type: int, Range: [0 to 232 - 1]

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.

BrickletRS232V2.set_status_led_config(config)¶

Parameters:	config – Type: int, Range: See constants, Default: 3
Returns:	None

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:

For config:

• 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()¶

Returns:	config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

For config:

• 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()¶

Returns:	temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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()¶

Returns:	None

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.get_identity()¶

Return Object:

uid – Type: str, Length: up to 8 connected_uid – Type: str, Length: up to 8 position – Type: chr, Range: ["a" to "h", "z"] hardware_version – 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] firmware_version – 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] 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¶

BrickletRS232V2.register_callback(callback_id, function)¶

Parameters:	callback_id – Type: int function – Type: callable
Returns:	None

Registers the given function with the given callback_id.

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

BrickletRS232V2.enable_read_callback()¶

Returns:	None

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

By default the callback is disabled.

BrickletRS232V2.disable_read_callback()¶

Returns:	None

Disables the CALLBACK_READ callback.

By default the callback is disabled.

BrickletRS232V2.is_read_callback_enabled()¶

Returns:	enabled – Type: bool, Default: False

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

BrickletRS232V2.set_frame_readable_callback_configuration(frame_size)¶

Parameters:	frame_size – Type: int, Unit: 1 B, Range: [0 to 9216], Default: 0
Returns:	None

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 2.0.3 (Plugin).

BrickletRS232V2.get_frame_readable_callback_configuration()¶

Returns:	frame_size – Type: int, Unit: 1 B, Range: [0 to 9216], Default: 0

Returns the callback configuration as set by set_frame_readable_callback_configuration().

New in version 2.0.3 (Plugin).

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:

def my_callback(param):
    print(param)

rs232_v2.register_callback(BrickletRS232V2.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters are described below.

BrickletRS232V2.CALLBACK_READ¶

Callback Parameters:	message – Type: [chr, ...], Length: variable

This callback is called if new data is available.

To enable this callback, use enable_read_callback().

Note

If reconstructing the value fails, the callback is triggered with None for message.

BrickletRS232V2.CALLBACK_ERROR_COUNT¶

Callback Parameters:	error_count_overrun – Type: int, Range: [0 to 232 - 1] error_count_parity – Type: int, Range: [0 to 232 - 1]

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

BrickletRS232V2.CALLBACK_FRAME_READABLE¶

Callback Parameters:	frame_count – Type: int, Range: [0 to 216 - 1]

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

New in version 2.0.3 (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.

BrickletRS232V2.get_api_version()¶

Return Object:	api_version – 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.

BrickletRS232V2.get_response_expected(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 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For function_id:

• 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_FRAME_READABLE_CALLBACK_CONFIGURATION = 14
• 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(function_id, response_expected)¶

Parameters:	function_id – Type: int, Range: See constants response_expected – Type: bool
Returns:	None

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:

• 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_FRAME_READABLE_CALLBACK_CONFIGURATION = 14
• 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 – Type: bool
Returns:	None

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

BrickletRS232V2.set_bootloader_mode(mode)¶

Parameters:	mode – Type: int, Range: See constants
Returns:	status – Type: int, Range: See constants

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:

For mode:

• 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

For status:

• 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()¶

Returns:	mode – Type: int, Range: See constants

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

For mode:

• 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 – Type: int, Unit: 1 B, Range: [0 to 232 - 1]
Returns:	None

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 – Type: [int, ...], Length: 64, Range: [0 to 255]
Returns:	status – Type: int, Range: [0 to 255]

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.write_uid(uid)¶

Parameters:	uid – Type: int, Range: [0 to 232 - 1]
Returns:	None

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()¶

Returns:	uid – Type: int, Range: [0 to 232 - 1]

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

Constants¶

BrickletRS232V2.DEVICE_IDENTIFIER¶

This constant is used to identify a RS232 Bricklet 2.0.

The get_identity() 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.

BrickletRS232V2.DEVICE_DISPLAY_NAME¶

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