BTstack Youngho Oh

Table of contents  BTstack features  BTstack Architecture  Host Controller Interface(HCI)  Bluetooth Stack  BLE event task  Test  Bluetooth 4.1 features

BTstack features  Can be operated both as a single mode or a dual mode stack.  Is well suited for small, resource-constraint devices such embedded systems as it is highly configurable and comes with an ultra small memory footprint.  Is to support devices for which the OS(ex. Linux, RTOS...) either does not provide a Bluetooth Stack.

BTstack Architecture Task C Bluetooth Stack HCI PAN1323ETU L2CAP ATT Run Loop BLE packet Sleep BLE HCI packet BLE Event Task BLE packet Task B Task A BLE packet

Host Controller Interface(HCI)  BTStack HCI provides UART interface to the PAN1323ETU and HAL Layer.  The format of HCI packets can refer to the BT Core 4.1 specification Volume 2 Part E.  HCI command defines in ‘hci_cmds.c’.

Bluetooth Stack  BTStack runs as two tasks.(BTStack task including Run Loop, BLE Event task)  BTStack uses a Run Loop to handle incoming data which represent UART communication interface.  Packet handler function is a message handler for L2CAP, ATT events.

BLE Event Task  BLE event task is implemented on a Ubinos Task.  The Main Application communicates with BLE event task via application-specific message, l2cap message(ex. Connection, disconnection, advertising, scan) over message queue.

Test EFM32GG STK3700 AS3933 PAN132 3 SPI UART Service Client Device CC2540 LF Transmitter GPIO Service Client Device LF BLE

Test  B-PniP Sequence Diagram

Test  Packet sniffer

Test

Bluetooth 4.1 features  Bluetooth 4.0 features are supported in the Bluetooth 4.1 core specification.  Exchange data more efficiently (Bluetooth Smart wearable device).  Device supports multiple roles simultaneously (Dual Mode Topology).  Device will be able to setup a dedicated channel for communication (future support of IPv6 at sensor level)