PRELIMINARY
CYW43438
8. Bluetooth Baseband Core
The Bluetooth Baseband Core (BBC) implements all of the time-critical functions required for high-performance Bluetooth operation.
The BBC manages the buffering, segmentation, and routing of data for all connections. It also buffers data that passes through it,
handles data flow control, schedules SCO/ACLTX/RX transactions, monitors Bluetooth slot usage, optimally segments and packages
data into baseband packets, manages connection status indicators, and composes and decodes HCI packets. In addition to these
functions, it independently handles HCI event types and HCI command types.
The following transmit and receive functions are also implemented in the BBC hardware to increase the reliability and security of data
before sending and receiving it over the air:
■ Symbol timing recovery, data deframing, forward error correction (FEC), header error control (HEC), cyclic redundancy check (CRC),
data decryption, and data dewhitening in the receiver.
■ Data framing, FEC generation, HEC generation, CRC generation, key generation, data encryption, and data whitening in the
transmitter.
8.1 Bluetooth 4.1 Features
The BBC supports all Bluetooth 4.1 features, with the following benefits:
■ Dual-mode classic Bluetooth and classic Low Energy (BT and BLE) operation.
■ Low energy physical layer
■ Low energy link layer
■ Enhancements to HCI for low energy
■ Low energy direct test mode
■ 128 AES-CCM secure connection for both BT and BLE
Note: The CYW43438 is compatible with the Bluetooth Low Energy operating mode, which provides a dramatic reduction in the power
consumption of the Bluetooth radio and baseband. The primary application for this mode is to provide support for low data rate
devices, such as sensors and remote controls.
8.2 Link Control Layer
The link control layer is part of the Bluetooth link control functions that are implemented in dedicated logic in the link control unit (LCU).
This layer contains the command controller that takes commands from the software, and other controllers that are activated or
configured by the command controller, to perform the link control tasks. Each task performs a different state in the Bluetooth link
controller.
■ Major states:
❐ Standby
❐ Connection
■ Substates:
❐ Page
❐ Page Scan
❐ Inquiry
❐ Inquiry Scan
❐ Sniff
❐ BLE Adv
❐ BLE Scan/Initiation
Document Number: 002-14796 Rev. *K
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