BLE GATT Fundamentals for Product Engineers
November 20, 20236 min read
Advertising before connection
A peripheral broadcasts advertising packets containing AD structures (flags, name, service UUIDs). A central scans, then sends a connection request. Tune the advertising interval to trade discovery latency against power.
Connection events
Once connected, communication happens in connection events spaced by the connection interval. A larger interval saves power; a smaller one reduces latency. Choose based on your product's interaction model.
Designing the GATT table
Model your device as Services containing Characteristics, each with properties (Read/Write/Notify). Use Notify for streaming sensor data so the central isn't forced to poll, and keep characteristic payloads within the negotiated MTU.