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org.bluetooth.characteristic.heart_rate_measurement

Name: Heart Rate Measurement

Type: org.bluetooth.characteristic.heart_rate_measurementDownload / View

Assigned Number: 0x2A37

Value Fields

Names Field Requirement Format Minimum Value Maximum Value Additional Information
Flags
Mandatory
8bit N/A N/A
Bit Field
Bit Size Name
Definition
Key Value Requires
0 1 Heart Rate Value Format bit
0 Heart Rate Value Format is set to UINT8. Units: beats per minute (bpm) C1
1 Heart Rate Value Format is set to UINT16. Units: beats per minute (bpm) C2
1 2 Sensor Contact Status bits
0 Sensor Contact feature is not supported in the current connection
1 Sensor Contact feature is not supported in the current connection
2 Sensor Contact feature is supported, but contact is not detected
3 Sensor Contact feature is supported and contact is detected
3 1 Energy Expended Status bit
0 Energy Expended field is not present
1 Energy Expended field is present. Units: kilo Joules C3
4 1 RR-Interval bit
0 RR-Interval values are not present.
1 One or more RR-Interval values are present. Units: 1/1024 seconds C4
5 3 Reserved for future use
Heart Rate Measurement Value (uint8)
Information:
Note: The format of the Heart Rate Measurement Value field is dependent upon bit 0 of the Flags field.
Unit:
org.bluetooth.unit.period.beats_per_minute
C1
uint8 N/A N/A None
Heart Rate Measurement Value (uint16)
Information:
Note: The format of the Heart Rate Measurement Value field is dependent upon bit 0 of the Flags field.
Unit:
org.bluetooth.unit.period.beats_per_minute
C2
uint16 N/A N/A None
Energy Expended
Information:
The presence of the Energy Expended field is dependent upon bit 3 of the Flags field.
Unit:
org.bluetooth.unit.energy.joule
C3
uint16 N/A N/A None
RR-Interval
Information:
The presence of the RR-Interval field is dependent upon bit 4 of the Flags field.

The RR-Interval value represents the time between two R-Wave detections.

Because several RR-Intervals may be measured between transmissions of the HEART RATE MEASUREMENT characteristic, multiple RR-Interval sub-fields may be present in the characteristic. The number of RR-Interval sub-fields present is determined by a combination of the overall length of the characteristic and whether or not the characteristic contains the Energy Expended field.

Where there are multiple RR-Interval values transmitted in the HEART RATE MEASUREMENT characteristic, the field uses the following format:

RR-Interval Value 0 (LSO...MSO), RR-Interval Value 1 (LSO...MSO), RR-Interval Value 2 (LSO...MSO), RR-Interval Value n (LSO...MSO).

Where the RR-Interval Value 0 is older than the RR-Interval Value 1.

RR-Interval Value 0 is transmitted first followed by the newer measurements.

Unit:
org.bluetooth.unit.time.second
C4
uint16 N/A N/A None

Note:

The fields in the above table are in the order of LSO to MSO. Where LSO = Least Significant Octet and MSO = Most Significant Octet.

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