10.Gatt 介绍

• Master (or "central") devices scan for other devices. Usually, the master is the smartphone/tablet/PC.
• Slave (or "peripheral") devices advertise and wait for connections. Usually, the slave is the BLE112/BLE113 module.
• Client devices access remote resources over a BLE link using the GATT protocol. Usually, the master is also the client.
• Server devices have a local database and access control methods, and provide resources to the remote client. Usually, the slave is also the server.
• You can use read, write, notify, or indicate operations to move data between the client and the server.
• Read and write operations are requested by the client and the server responds (or acknowledges).
• Notify and indicate operations are enabled by the client but initiated by the server, providing a way to push data to the client.
• Notifications are unacknowledged, while indications are acknowledged. Notifications are therefore faster, but less reliable
• Example gatt.xml content with GATT server structure for a "typical" custom BLE peripheral device.