pygmc.connection package

Submodules

pygmc.connection.connection module

Represent a USB connection to a GMC.

This is the communication class.

class pygmc.connection.connection.Connection(timeout=5)[source]

Bases: object

Represent a connection to a GMC device.

Either user provided parameters or a best-guess auto-connect. Effectively a wrapper for pyserial for GMC specific tasks.

close_connection() → None[source]

Close connection.

connect(port=None, baudrate=None, vid=None, pid=None, description=None, hardware_id='1A86:7523') → None[source]

Connect to device.

If all parameters are None, _auto_connect() flow is used which attempts to connect to all available ports. If ANY parameter is given; it refines the search, any matches are considered. Parameters are used as an OR search.

Parameters:

  • port (str | None, optional) – Exact port (device dev path / com port) e.g. ‘/dev/ttyUSB0’ If port is specified, the following kwargs are ignored: vid, pid, description, hardware_id.

  • baudrate (int | None) – Device baudrate. Leave None to auto-detect baudrate. Only applicable when port is specified.

  • vid (str | None, optional) – Device vendor ID as hex, by default None

  • pid (str | None, optional) – Device product ID as hex, by default None

  • description (str | None, optional) – Device description, by default None

  • hardware_id (str | None, optional) – Device hwid, by default “1A86:7523” e.g. ‘USB VID:PID=1A86:7523 LOCATION=2-1’

Raises:

ConnectionError – _description_

connect_exact(port, baudrate) → None[source]

Connect with exact user provided parameters.

No searching port, no searching baudrate. i.e. fast.

Parameters:

  • port (str) – Port. e.g. linux /dev/ttyUSB0 or windows COM3

  • baudrate (int) – Baudrate e.g. 115200

connect_user_provided(connection) → None[source]

User does their own thing and gives a serial.Serial like class.

Parameters:

connection (serial.Serial) – A serial.Serial like class (pyserial)

get(cmd, wait_sleep=0.3) → bytes[source]

Write command to device and get response.

Only use in development/learning environment. May give incomplete/empty response if device is busy.

Parameters:

  • cmd (bytes) – Write command e.g. <GETVER>>

  • wait_sleep (float, optional) – Time to sleep to give device time to write, by default 0.3

Returns:

Device response

Return type:

bytes

get_exact(cmd, expected=b'', size=None) → bytes[source]

Write and read exact.

Write command to device, provide expected LF or size (bytes), wait until either LF, size, or timeout is reached, then return device response.

Parameters:

  • cmd (bytes) – Write command e.g. <GETVER>>

  • expected (bytes, optional) – Expected end char, by default b’’

  • size (int | None, optional) – Expected response size, by default None

Returns:

Device response

Return type:

bytes

read(wait_sleep=0.3) → bytes[source]

Read all available data.

Which may be incomplete. (noob/newbie method)

Parameters:

wait_sleep (float, optional) – Time to sleep to give device time to write, by default 0.3

Returns:

Device response

Return type:

bytes

read_until(expected=b'', size=None) → bytes[source]

Read device data until expected LF is reached or expected result size is reached.

Waits until conditions met or timeout. Some data has ‘n’ which causes reading to stop. default changed from b’n’ to b’’

Parameters:

  • expected (bytes, optional) – Expected end character, by default b’’

  • size (None | int, optional) – Length of expected bytes, by default None

Returns:

Device response

Return type:

bytes

reset_buffers() → None[source]

Reset input & output buffers on pyserial connection.

reset_input_buffer(): Clear input buffer, discarding all that is in the buffer. reset_output_buffer(): Clear output buffer, aborting the current output and discarding all that is in the buffer.

write(cmd: bytes) → None[source]

Write command to device.

Parameters:

cmd (bytes) – Write command e.g. <GETVER>>

Module contents