Bluetooth GATT Characteristic Reference
Cycling Power Measurement (0x2A63)
The Cycling Power Measurement characteristic is a variable length structure containing a Flags field, an Instantaneous Power field and, based on the contents of the Flags field, may contain one or more additional fields as shown in the table below.
Quick Summary
Payload length is profile-defined or variable based on field formats. This page is generated from official GATT XML and presented as implementation-ready guidance.
At a Glance
Key reference details for BLE implementation, interoperability testing, and AI-assisted troubleshooting.
| Property | Value |
|---|---|
| Name | Cycling Power Measurement |
| UUID | 0x2A63 |
| Type | org.bluetooth.characteristic.cycling_power_measurement |
| XML Root | Characteristic |
| Source File | org.bluetooth.characteristic.cycling_power_measurement.xml |
| Field Count | 17 |
Field Specification
Parsed field definitions from the source XML value structure.
| Field | Requirement | Format | Unit | Exponent | Notes |
|---|---|---|---|---|---|
| Flags | Mandatory | 16bit | - | - | - |
| Instantaneous Power | Mandatory | sint16 | org.bluetooth.unit.power.watt | 0 | Unit is in watts with a resolution of 1. |
| Pedal Power Balance | Optional | uint8 | org.bluetooth.unit.percentage | - | Unit is in percentage with a resolution of 1/2. |
| Accumulated Torque | Optional | uint16 | org.bluetooth.unit.moment_of_force.newton_metre | - | Unit is in newton metres with a resolution of 1/32. |
| Wheel Revolution Data - Cumulative Wheel Revolutions | C1 | uint32 | org.bluetooth.unit.unitless | 0 | Unitless |
| Wheel Revolution Data - Last Wheel Event Time | C1 | uint16 | org.bluetooth.unit.time.second | - | Unit is in seconds with a resolution of 1/2048. |
| Crank Revolution Data- Cumulative Crank Revolutions | C2 | uint16 | org.bluetooth.unit.unitless | 0 | Unitless |
| Crank Revolution Data- Last Crank Event Time | C2 | uint16 | org.bluetooth.unit.time.second | - | Unit is in seconds with a resolution of 1/1024. |
| Extreme Force Magnitudes - Maximum Force Magnitude | C3 | sint16 | org.bluetooth.unit.force.newton | 0 | Unit is in newtons with a resolution of 1. |
| Extreme Force Magnitudes - Minimum Force Magnitude | C3 | sint16 | org.bluetooth.unit.force.newton | 0 | Unit is in newtons with a resolution of 1. |
| Extreme Torque Magnitudes- Maximum Torque Magnitude | C4 | sint16 | org.bluetooth.unit.moment_of_force.newton_metre | - | Unit is in newton metres with a resolution of 1/32. |
| Extreme Torque Magnitudes- Minimum Torque Magnitude | C4 | sint16 | org.bluetooth.unit.moment_of_force.newton_metre | - | Unit is in newton metres with a resolution of 1/32. |
| Extreme Angles - Maximum Angle | C5 | uint12 | org.bluetooth.unit.plane_angle.degree | 0 | Unit is in degrees with a resolution of 1 |
| Extreme Angles - Minimum Angle | C5 | uint12 | org.bluetooth.unit.plane_angle.degree | 0 | Unit is in degrees with a resolution of 1. |
| Top Dead Spot Angle | Optional | uint16 | org.bluetooth.unit.plane_angle.degree | 0 | Unit is in degrees with a resolution of 1. |
| Bottom Dead Spot Angle | Optional | uint16 | org.bluetooth.unit.plane_angle.degree | 0 | Unit is in degrees with a resolution of 1. |
| Accumulated Energy | Optional | uint16 | org.bluetooth.unit.energy.joule | 3 | Unit is in kilojoules with a resolution of 1. |
Bit Map
Bit-level enumerations extracted from the XML BitField definition.
| Field | Bit | Size | Name | 0 Means | 1 Means |
|---|---|---|---|---|---|
| Flags | 0 | 1 | Pedal Power Balance Present | False | True |
| Flags | 1 | 1 | Pedal Power Balance Reference | Unknown | Left |
| Flags | 2 | 1 | Accumulated Torque Present | False | True |
| Flags | 3 | 1 | Accumulated Torque Source | Wheel Based | Crank Based |
| Flags | 4 | 1 | Wheel Revolution Data Present | False | True |
| Flags | 5 | 1 | Crank Revolution Data Present | False | True |
| Flags | 6 | 1 | Extreme Force Magnitudes Present | False | True |
| Flags | 7 | 1 | Extreme Torque Magnitudes Present | False | True |
| Flags | 8 | 1 | Extreme Angles Present | False | True |
| Flags | 9 | 1 | Top Dead Spot Angle Present | False | True |
| Flags | 10 | 1 | Bottom Dead Spot Angle Present | False | True |
| Flags | 11 | 1 | Accumulated Energy Present | False | True |
| Flags | 12 | 1 | Offset Compensation Indicator | False | True |
Byte Layout and Decode
Payload length is profile-defined or variable based on field formats.
function decodePayload(dataView, offset = 0) {
// Parse flags (16bit) according to Bluetooth format rules.
const instantaneous_power = dataView.getInt16(offset + 0, true);
const pedal_power_balance = dataView.getUint8(offset + 2);
const accumulated_torque = dataView.getUint16(offset + 3, true);
const wheel_revolution_data_cumulative_wheel_revolutions = dataView.getUint32(offset + 5, true);
const wheel_revolution_data_last_wheel_event_time = dataView.getUint16(offset + 9, true);
const crank_revolution_data_cumulative_crank_revolutions = dataView.getUint16(offset + 11, true);
const crank_revolution_data_last_crank_event_time = dataView.getUint16(offset + 13, true);
const extreme_force_magnitudes_maximum_force_magnitude = dataView.getInt16(offset + 15, true);
const extreme_force_magnitudes_minimum_force_magnitude = dataView.getInt16(offset + 17, true);
return { flags, instantaneous_power, pedal_power_balance, accumulated_torque, wheel_revolution_data_cumulative_wheel_revolutions, wheel_revolution_data_last_wheel_event_time };
}Use Cases and Integration Notes
BLE Telemetry
Map characteristic values into dashboards and alerts for device observability.
Firmware Regression
Compare decoded fields across builds to detect protocol or scaling changes.
App Integration
Build stable parsing paths that convert raw payloads into typed app models.
Implementation Checklist
- Validate payload length and mandatory fields before decode.
- Decode with Bluetooth-specified signedness, unit, and exponent handling.
- Convert units at presentation boundaries to avoid drift in business logic.
- Persist raw packets and decoded values for reproducible troubleshooting.
FAQ
What is Cycling Power Measurement in Bluetooth GATT?
Cycling Power Measurement is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.cycling_power_measurement and UUID 0x2A63.
What UUID identifies Cycling Power Measurement?
The UUID for Cycling Power Measurement is 0x2A63.
How should I parse Cycling Power Measurement?
Payload length is profile-defined or variable based on field formats.
Where does this definition come from?
This page is generated from the Bluetooth SIG mirror XML in the oesmith/gatt-xml repository.
How does this page support BLE implementation?
The page combines structured tables, practical Q&A, and JSON-LD metadata to help teams validate integrations and troubleshoot consistently.