CYW20702
3. Bluetooth Baseband Core
The Bluetooth Baseband Core (BBC) implements the time critical functions required for high-performance Bluetooth and Low Energy
operation. The BBC manages buffering, segmentation, and data routing for all connections. It also buffers data that passes through
it, handles data flow control, schedules SCO/ACL Tx/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.
3.1 Transmit and Receive Functions
The following transmit and receive functions are implemented in the BBC hardware to increase the reliability and security of the
Tx/Rx data before sending the data over the air:
In the transmitter:
■ Data framing
■ Forward Error Correction (FEC) generation
■ Header Error Control (HEC) generation
■ Cyclic Redundancy Check (CRC) generation
■ Key generation
■ Data encryption
■ Data whitening
In the receiver:
■ Symbol timing recovery
■ Data deframing
■ FEC
■ HEC
■ CRC
■ Data decryption
■ Data dewhitening
3.2 Bluetooth 4.0 + EDR Features
The CYW20702 supports Bluetooth 4.0 + EDR and Low Energy, including the following options:
■ A whitelist size of 25
■ Enhanced Power Control
■ HCI Read Encryption Key Size command
The CYW20702 provides full support for Bluetooth 2.1 + EDR additional features:
■ Secure Simple Pairing (SSP)
■ Encryption Pause Resume (EPR)
■ Enhance Inquiry Response (EIR)
■ Link Supervision Time Out (LSTO)
■ Sniff SubRating (SSR)
■ Erroneous Data (ED)
■ Packet Boundary Flag (PBF)
3.3 Frequency Hopping Generator
The frequency hopping sequence generator selects the correct hopping channel number, based on the link controller state, Bluetooth
clock, and device address.
3.4 Link Control Layer
The Link Control layer is part of the Bluetooth link control functions implemented in dedicated logic in the Link Control Unit (LCU).
This layer consists of 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.
There are two major states–Standby and Connection. Each task establishes a different state in the Bluetooth Link Controller. In
addition, there are eight substates—Page, Page Scan, Inquiry, Inquiry Scan, Sniff, and Sniff SubRating.
Document Number: 002-14773 Rev. *L
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