ADVANCE
CYW43570
5. 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 reliability and security of the TX/
RX data before sending 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.
5.1 Bluetooth 4.1 Features
The BBC supports all Bluetooth 4.1 features with the following benefits:
■ Dual-mode Bluetooth low energy (BT and BLE operation)
■ Extended inquiry response (EIR): Shortens the time to retrieve the device name, specific profile, and operating mode.
■ Encryption pause resume (EPR): Enables the use of Bluetooth technology in a much more secure environment.
■ Sniff subrating (SSR): Optimizes power consumption for low duty cycle asymmetric data flow, which subsequently extends battery
life.
■ Secure simple pairing (SSP): Reduces the number of steps for connecting two devices, with minimal or no user interaction required.
■ Link supervision time out (LSTO): Additional commands added to HCI and link management protocol (LMP) for improved link time-
out supervision.
■ QoS enhancements: Changes to data traffic control, which results in better link performance. Audio, human interface device (HID),
bulk traffic, SCO, and enhanced SCO (eSCO) are improved with the erroneous data (ED) and packet boundary flag (PBF) enhance-
ments.
5.2 Bluetooth Low Energy
The CYW43570 supports the Bluetooth Low Energy operating mode.
5.3 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 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. Each task performs a different state in the Bluetooth link
controller.
■ Major states:
❐ Standby
❐ Connection
■ Substates:
❐ Page
❐ Page Scan
❐ Inquiry
❐ Inquiry Scan
❐ Sniff
Document Number: 002-15054 Rev. *I
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