hvl_ccb.comm.serial

Communication protocol for serial ports. Makes use of the pySerial library.

class SerialCommunication(configuration)

Bases: AsyncCommunicationProtocol

Implements the Communication Protocol for serial ports.

close()

Close the serial connection.

static config_cls()

Return the default configdataclass class.

Returns:

a reference to the default configdataclass class

property is_open: bool

Flag indicating if the serial port is open.

Returns:

True if the serial port is open, otherwise False

open()

Open the serial connection.

Raises:

SerialCommunicationIOError – when communication port cannot be opened.

read_bytes() → bytes

Read the bytes from the serial port till the terminator is found. The input buffer may hold additional lines afterwards.

This method uses self.access_lock to ensure thread-safety.

Returns:

Bytes read from the serial port; b’’ if there was nothing to read.

Raises:

SerialCommunicationIOError – when communication port is not opened

read_single_bytes(size: int = 1) → bytes

Read the specified number of bytes from the serial port. The input buffer may hold additional data afterwards.

Returns:

Bytes read from the serial port; b’’ if there was nothing to read.

write_bytes(data: bytes) → int

Write bytes to the serial port.

This method uses self.access_lock to ensure thread-safety.

Parameters:

data – data to write to the serial port

Returns:

number of bytes written

Raises:

SerialCommunicationIOError – when communication port is not opened

class SerialCommunicationBytesize(value=<no_arg>, names=None, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: ValueEnum

Serial communication bytesize.

EIGHTBITS = 8

FIVEBITS = 5

SEVENBITS = 7

SIXBITS = 6

class SerialCommunicationConfig(terminator: bytes = b'\r\n', encoding: str = 'utf-8', encoding_error_handling: str = 'strict', wait_sec_read_text_nonempty: int | float = 0.5, default_n_attempts_read_text_nonempty: int = 10, port: str | None = None, baudrate: int = 9600, parity: str | ~hvl_ccb.comm.serial.SerialCommunicationParity = <SerialCommunicationParity.NONE: 'N'>, stopbits: int | float | ~hvl_ccb.comm.serial.SerialCommunicationStopbits = <SerialCommunicationStopbits.ONE: 1>, bytesize: int | ~hvl_ccb.comm.serial.SerialCommunicationBytesize = <SerialCommunicationBytesize.EIGHTBITS: 8>, timeout: int | float = 2)

Bases: AsyncCommunicationProtocolConfig

Configuration dataclass for SerialCommunication.

Bytesize

alias of SerialCommunicationBytesize

Parity

alias of SerialCommunicationParity

Stopbits

alias of SerialCommunicationStopbits

baudrate: int = 9600

Baudrate of the serial port

bytesize: int | SerialCommunicationBytesize = 8

Size of a byte, 5 to 8

clean_values()

create_serial_port() → Serial

Create a serial port instance according to specification in this configuration

Returns:

Closed serial port instance

force_value(fieldname, value)

Forces a value to a dataclass field despite the class being frozen.

NOTE: you can define post_force_value method with same signature as this method to do extra processing after value has been forced on fieldname.

Parameters:

• fieldname – name of the field

• value – value to assign

classmethod keys() → Sequence[str]

Returns a list of all configdataclass fields key-names.

Returns:

a list of strings containing all keys.

classmethod optional_defaults() → dict[str, object]

Returns a list of all configdataclass fields, that have a default value assigned and may be optionally specified on instantiation.

Returns:

a list of strings containing all optional keys.

parity: str | SerialCommunicationParity = 'N'

Parity to be used for the connection.

port: str | None = None

Port is a string referring to a COM-port (e.g. 'COM3') or a URL. The full list of capabilities is found on the pyserial documentation.

classmethod required_keys() → Sequence[str]

Returns a list of all configdataclass fields, that have no default value assigned and need to be specified on instantiation.

Returns:

a list of strings containing all required keys.

stopbits: int | float | SerialCommunicationStopbits = 1

Stopbits setting, can be 1, 1.5 or 2.

terminator_str() → str

timeout: int | float = 2

Timeout in seconds for the serial port

exception SerialCommunicationIOError

Bases: OSError, CommunicationError

Serial communication related I/O errors.

class SerialCommunicationParity(value=<no_arg>, names=None, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: ValueEnum

Serial communication parity.

EVEN = 'E'

MARK = 'M'

NAMES = {'E': 'Even', 'M': 'Mark', 'N': 'None', 'O': 'Odd', 'S': 'Space'}

NONE = 'N'

ODD = 'O'

SPACE = 'S'

class SerialCommunicationStopbits(value=<no_arg>, names=None, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: ValueEnum

Serial communication stopbits.

ONE = 1

ONE_POINT_FIVE = 1.5

TWO = 2