Bluetooth GATT Characteristic Reference
Object Size (0x2AC0)
Object Size is defined in the Bluetooth GATT XML specification with type org.bluetooth.characteristic.object_size and UUID 0x2AC0.
Quick Summary
Payload length is 8 bytes. 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 | Object Size |
| UUID | 0x2AC0 |
| Type | org.bluetooth.characteristic.object_size |
| XML Root | Characteristic |
| Source File | org.bluetooth.characteristic.object_size.xml |
| Field Count | 2 |
Field Specification
Parsed field definitions from the source XML value structure.
| Field | Requirement | Format | Unit | Exponent | Notes |
|---|---|---|---|---|---|
| Current Size | Mandatory | uint32 | - | 0 | - |
| Allocated Size | Mandatory | uint32 | - | 0 | - |
Byte Layout and Decode
Payload length is 8 bytes.
function decodePayload(dataView, offset = 0) {
const current_size = dataView.getUint32(offset + 0, true);
const allocated_size = dataView.getUint32(offset + 4, true);
return { current_size, allocated_size };
}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 Object Size in Bluetooth GATT?
Object Size is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.object_size and UUID 0x2AC0.
What UUID identifies Object Size?
The UUID for Object Size is 0x2AC0.
How should I parse Object Size?
Payload length is 8 bytes.
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.