XR18W750 Datasheet, PDF (8/44 Pages) Exar Corporation – WIRELESS UART CONTROLLER

XR18W750
WIRELESS UART CONTROLLER
REV. 1.0.0
2.2 Point-to-Multipoint (Group Mode)
Point-to-multipoint communication, also known as Group mode, is when one master station transmits a packet
to all Wireless UART chipsets with the same Group ID. All Wireless UART chipsets with the same Group ID
will receive the message. No ACK will be sent by the receiving stations and no ACK is expected by the master
station. The Source and Destination ID is not checked in this communication mode.
2.3 Broadcast
The broadcast mode is when one master station transmits a packet and is received by all Wireless UART
chipsets that are on the same channel frequency and that have the same AES security key. In this case, the
Source ID, Destination ID and Group ID are not checked. No ACK will be sent by the receiving stations and no
ACK is expected by the master station.
3.0 ENHANCED UART DESCRIPTION
3.1 Serial Mode Interface
In the serial mode, the enhanced UART is controlled by the 8051 processor. The enhanced UART can
communicate with another serial port via RS-232, RS-485, or RS-422. A typical connection for the serial mode
of operation is shown below.
FIGURE 3. XR18W750 TYPICAL CONNECTIONS (SERIAL MODE)
TX
RX
RTS#
CTS#
DTR#
DSR#
CD#
RI#
TXRDY#
RXRDY#
VCC
VCC
A2:A0
D7:D0
CS#
IOW#
TX ^IOR#
RX
INT
RTS#
CTS#
DTR#
DSR#
CD#
RI#
TXRDY#
RXRDY#
16/68#
UART
S/P#
A2:A0
D7:D0
CS#
IOW#
IOR#
INT
8051
Microprocessor
UART
In the serial mode, the external serial port will need to communicate with the UART via AT commands.
3.1.1 Auto Baud Rate Detect
Upon power-up, the XR18W750 can automatically detect any baud rate from 1200 bps to 230.4Kbps in the
parallel mode or from 1200 bps to 921.6Kbps in the serial mode. The only requirement is that the carriage
return character (0x0D) is sent twice to the enhanced UART. After that the enhanced UART will be configured
for the correct baud rate.
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