src.bluetooth_sig.gatt.characteristics.cgm_feature¶

CGM Feature characteristic implementation.

Implements the CGM Feature characteristic (0x2AA8). Fixed-size structure of 6 bytes: 24-bit feature flags + packed nibble type/location + 16-bit E2E-CRC.

Structure (from GSS YAML):: CGM Feature (3 bytes, boolean[24]) CGM Type-Sample Location (1 byte, two 4-bit nibbles packed) E2E-CRC (2 bytes, uint16) – always present per spec

References

Bluetooth SIG Continuous Glucose Monitoring Service org.bluetooth.characteristic.cgm_feature (GSS YAML)

Classes¶

Name	Description
`CGMFeatureCharacteristic`	CGM Feature characteristic (0x2AA8).
`CGMFeatureData`	Parsed data from CGM Feature characteristic.
`CGMFeatureFlags`	CGM Feature flags (24-bit).
`CGMSampleLocation`	CGM sample location (upper nibble).
`CGMType`	CGM sample type (lower nibble).

Module Contents¶

class src.bluetooth_sig.gatt.characteristics.cgm_feature.CGMFeatureCharacteristic¶

Bases: src.bluetooth_sig.gatt.characteristics.base.BaseCharacteristic[CGMFeatureData]

CGM Feature characteristic (0x2AA8).

Reports the supported features, sample type, sample location, and E2E-CRC for a CGM sensor. Fixed 6-byte structure.

expected_length: int = 6¶

expected_type¶

class src.bluetooth_sig.gatt.characteristics.cgm_feature.CGMFeatureData¶

Bases: msgspec.Struct

Parsed data from CGM Feature characteristic.

features¶: 24-bit CGM feature flags.

cgm_type¶: CGM sample type.

sample_location¶: CGM sample location.

e2e_crc¶: E2E-CRC value.

cgm_type: CGMType¶

e2e_crc: int¶

features: CGMFeatureFlags¶

sample_location: CGMSampleLocation¶

class src.bluetooth_sig.gatt.characteristics.cgm_feature.CGMFeatureFlags¶

Bases: enum.IntFlag

CGM Feature flags (24-bit).

CALIBRATION_SUPPORTED = 1¶

CGM_QUALITY_SUPPORTED = 65536¶

CGM_TREND_INFORMATION_SUPPORTED = 32768¶

DEVICE_SPECIFIC_ALERT = 32¶

E2E_CRC_SUPPORTED = 4096¶

GENERAL_DEVICE_FAULT = 2048¶

HYPER_ALERTS = 8¶

HYPO_ALERTS = 4¶

LOW_BATTERY_DETECTION = 512¶

MULTIPLE_BOND_SUPPORTED = 8192¶

MULTIPLE_SESSIONS_SUPPORTED = 16384¶

PATIENT_HIGH_LOW_ALERTS = 2¶

RATE_ALERTS = 16¶

SENSOR_MALFUNCTION_DETECTION = 64¶

SENSOR_RESULT_HIGH_LOW_DETECTION = 256¶

SENSOR_TEMP_HIGH_LOW_DETECTION = 128¶

SENSOR_TYPE_ERROR_DETECTION = 1024¶

class src.bluetooth_sig.gatt.characteristics.cgm_feature.CGMSampleLocation¶

Bases: enum.IntEnum

CGM sample location (upper nibble).

ALTERNATE_SITE_TEST = 2¶

CONTROL_SOLUTION = 4¶

EARLOBE = 3¶

FINGER = 1¶

NOT_AVAILABLE = 15¶

SUBCUTANEOUS_TISSUE = 5¶

class src.bluetooth_sig.gatt.characteristics.cgm_feature.CGMType¶

Bases: enum.IntEnum

CGM sample type (lower nibble).

ARTERIAL_PLASMA = 6¶

ARTERIAL_WHOLE_BLOOD = 5¶

CAPILLARY_PLASMA = 2¶

CAPILLARY_WHOLE_BLOOD = 1¶

CONTROL_SOLUTION = 10¶

INTERSTITIAL_FLUID = 9¶

UNDETERMINED_PLASMA = 8¶

UNDETERMINED_WHOLE_BLOOD = 7¶

VENOUS_PLASMA = 4¶

VENOUS_WHOLE_BLOOD = 3¶