BCM20730 Data Sheet
Bluetooth Baseband Core
Certain applications may make use of the BCM20730 Baseband Fast Connect (BFC) mechanism for power
savings and lower latencies not achievable by using even long sniff intervals by completely eliminating the need
to maintain an RF link, while still being able to establish ACL and L2CAP connections much faster than regular
methods.
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 data routing for all connections. It
also buffers data that passes through it, handles data flow control, schedules 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.
The following transmit and receive functions are also implemented in the BBC hardware to increase TX/RX data
reliability and security before sending over the air:
• Receive Functions: symbol timing recovery, data deframing, forward error correction (FEC), header error
control (HEC), cyclic redundancy check (CRC), data decryption, and data dewhitening.
• Transmit Functions: data framing, FEC generation, HEC generation, CRC generation, link key generation,
data encryption, and data whitening.
Frequency Hopping Generator
The frequency hopping sequence generator selects the correct hopping channel number depending on the link
controller state, Bluetooth clock, and device address.
E0 Encryption
The encryption key and the encryption engine are implemented using dedicated hardware to reduce software
complexity and provide minimal processor intervention.
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, which takes software commands,
and other controllers that are activated or configured by the Command Controller to perform the link control
tasks. Each task performs a different Bluetooth link controller state. STANDBY and CONNECTION are the two
major states. In addition, there are five substates: page, page scan, inquiry, inquiry scan, and sniff.
BROADCOM
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September 9, 2013 • 20730-DS108-R
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