Bluetooth GATT Characteristic Reference
Exact Time 256 (0x2A0C)
Exact Time 256 is defined in the Bluetooth GATT XML specification with type org.bluetooth.characteristic.exact_time_256 and UUID 0x2A0C.
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 | Exact Time 256 |
| UUID | 0x2A0C |
| Type | org.bluetooth.characteristic.exact_time_256 |
| XML Root | Characteristic |
| Source File | org.bluetooth.characteristic.exact_time_256.xml |
| Field Count | 2 |
Field Specification
Parsed field definitions from the source XML value structure.
| Field | Requirement | Format | Unit | Exponent | Notes |
|---|---|---|---|---|---|
| Day Date Time | Mandatory | N/A | - | - | Reference the Time Characteristic |
| Fractions256 | Mandatory | uint8 | - | - | 1/256th of a second |
Byte Layout and Decode
Payload length is profile-defined or variable based on field formats.
function decodePayload(dataView, offset = 0) {
// Parse day_date_time (N/A) according to Bluetooth format rules.
const fractions256 = dataView.getUint8(offset + 0);
return { day_date_time, fractions256 };
}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 Exact Time 256 in Bluetooth GATT?
Exact Time 256 is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.exact_time_256 and UUID 0x2A0C.
What UUID identifies Exact Time 256?
The UUID for Exact Time 256 is 0x2A0C.
How should I parse Exact Time 256?
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.