BCI Core-8

class gpype.backend.sources.bci_core8.BCICore8

Bases: AmplifierSource

g.tec BCI Core-8 amplifier source for wireless EEG acquisition.

Interface to g.tec BCI Core-8 wireless EEG amplifier using BLE. Supports 8-channel acquisition at 250 Hz.

PORT_BUF_LEVEL = 'buffer_level'

Optional buffer level monitoring output port name

SCANNING_TIMEOUT_S = 10

Bluetooth scanning timeout in seconds

SAMPLING_RATE = 250

Fixed sampling rate for BCI Core-8 amplifier in Hz

MAX_NUM_CHANNELS = 8

Maximum number of supported EEG channels

DEFAULT_BUFFER_DELAY_MS = 40

Default internal buffer delay in milliseconds

TARGET_FILL_RATIO = 0.5

Target buffer fill ratio for stable operation

FILL_RATIO_ALPHA = 0.9995

Smoothing factor for buffer fill ratio calculation

FILL_RATIO_CORRECTION_INTERVAL_S = 1.0

Correction interval for buffer timing in seconds

NUM_UNDERRUNS_ALLOWED = 10

Maximum allowed consecutive buffer underruns

DEVICE_DELAY_MS = 18

Hardware delay compensation in milliseconds

class Configuration

Bases: Configuration

Configuration class for BCI Core-8 specific parameters.

class Keys

Bases: Keys

Configuration keys for BCI Core-8 settings.

OUTPUT_BUFFER_LEVEL = 'output_buffer_level'

BUFFER_DELAY_MS = 'buffer_delay_ms'

__init__(serial=None, channel_count=None, frame_size=None, buffer_delay_ms=None, output_buffer_level=None, **kwargs)

Initialize BCI Core-8 amplifier source.

Parameters:

• serial (Optional[str]) – Serial number of target device. Uses first discovered if None.

• channel_count (Optional[int]) – Number of EEG channels (1-8). Defaults to 8.

• frame_size (Optional[int]) – Samples per processing frame.

• buffer_delay_ms (Optional[int]) – Internal buffer delay in milliseconds.

• output_buffer_level (Optional[bool]) – Enable buffer level monitoring output.

• **kwargs – Additional arguments for parent AmplifierSource.

start()

Start BCI Core-8 amplifier and begin data acquisition.

Initializes buffers, starts background thread, establishes BLE connection, and begins real-time data streaming.

Raises:

• ConnectionError – If amplifier connection fails.

• RuntimeError – If background thread creation fails.

Return type:

None

setup(data, port_context_in)

Setup output port contexts for BCI Core-8 data streams.

Parameters:

• data (dict[str, ndarray]) – Input data arrays (empty for source nodes).

• port_context_in (dict[str, dict]) – Input port contexts (empty for source nodes).

Return type:

dict[str, dict]

Returns:

Dictionary of output port contexts with 250 Hz sampling rate.

stop()

Stop BCI Core-8 amplifier and clean up resources.

Stops data acquisition, terminates background thread, and disconnects from amplifier hardware.

step(data)

Retrieve processed data frames from the amplifier.

Returns data frames when decimation step is active. Handles buffer underruns by providing zero-filled frames to maintain continuity.

Parameters:

data (dict[str, ndarray]) – Input data dictionary (unused for source nodes).

Return type:

dict[str, ndarray]

Returns:

Dictionary containing EEG data and optionally buffer level data, or None if not a decimation step.