CYW20738
1.4 Infrared Learning
The CYW20738 includes hardware support for infrared learning. The hardware can detect both modulated and unmodulated signals.
For modulated signals, the CYW20738 can detect carrier frequencies between 10 kHz and 500 kHz and the duration that the signal
is present or absent. The CYW20738 firmware driver supports further analysis and compression of learned signal. The learned signal
can then be played back through the CYW20738 IR TX subsystem. See Figure 3.
Figure 3. Infrared RX
VCC
U3
D2
PHOTODIODE
20738
IR RX
1.5 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 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.
1.5.1 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.
1.5.2 E0 Encryption
The encryption key and the encryption engine are implemented using dedicated hardware to reduce software complexity and provide
minimal processor intervention.
1.5.3 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, 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.
1.5.4 Adaptive Frequency Hopping
The CYW20738 gathers link quality statistics on a channel-by-channel basis to facilitate channel assessment and channel map
selection. The link quality is determined by using both RF and baseband signal processing to provide a more accurate frequency hop
map.
1.5.5 Bluetooth Low Energy
The CYW20738 supports the Bluetooth Low Energy (BLE) operating mode.
Document Number: 002-14891 Rev. *C
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