CYW20702
5.4 UART Interface
The UART physical interface is a standard, 4-wire interface (RX, TX, RTS, CTS) with adjustable baud rates from 9600 bps to 4.0
Mbps. The interface features an automatic baud rate detection capability that returns a baud rate selection. Alternatively, the baud
rate can be selected via a vendor-specific UART HCI command. The interface supports Bluetooth UART HCI (H4) specifications. The
default baud rate for H4 is 115.2 Kbaud.
The following baud rates are supported:
■ 9600
■ 14400
■ 19200
■ 28800
■ 38400
■ 57600
■ 115200
■ 230400
■ 460800
■ 921600
■ 144444
■ 150000
■ 2000000
■ 3000000
■ 3250000
■ 3692000
■ 4000000
Normally, the UART baud rate is set by a configuration record downloaded after reset or by automatic baud rate detection. The host
does not need to adjust the baud rate. Support for changing the baud rate during normal HCI UART operation is provided through a
vendor-specific command.
The CYW20702 UART operates with the host UART correctly, provided the combined baud rate error of the two devices is within ±2%.
5.4.1 HCI 3-Wire Transport (UART H5)
The CYW20702 supports H5 UART transport for serial UART communications. H5 reduces the number of signal lines required by
eliminating CTS and RTS, when compared to H4.
H5 requires the use of an external LPO. CTS must be pulled low.
Document Number: 002-14773 Rev. *L
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