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Operation
Serial interface
The XTC RF Module provides a serial interface to an RF link. The XTC RF Module converts serial data to
RF data and sends that data to any over-the-air compatible device in an RF network. The device can
communicate through its serial port with any logic and voltage compatible universal asynchronous
receiver/transmitter (UART), or through a level translator to any serial device.
UART data flow
Devices that have a UART interface connect directly to the pins of the XTC RF Module as shown in the
following figure. The figure shows system data flow in a UART-interfaced environment. Low-asserted
signals have a horizontal line over the signal name.
Serial data
A device sends data to the XTC RF Module's UART through pin 4 DIN as an asynchronous serial signal.
When the device is not transmitting data, the signals should idle high.
For serial communication to occur, you must configure the UART of both devices (the microcontroller
and the XTC RF Module) with compatible settings for the baud rate, parity, start bits, stop bits, and
data bits.
Each data byte consists of a start bit (low), 8 data bits (least significant bit first) and a stop bit (high).
The following diagram illustrates the serial bit pattern of data passing through the device. The
diagram shows UART data packet 0x1F (decimal number 31) as transmitted through the device.
Serial flow control
The RTS and CTS device pins provide RTS and/or CTS flow control. CTS flow control signals the host to
stop sending serial data to the device. RTS flow control lets the host signal the device so it will not
send the data in the serial transmit buffer out the UART. Use the D6 and D7 commands to enable RTS
and CTS flow control.
XBee®/XBee-PRO XTend Compatible (XTC) DigiMesh RF Module User Guide
Serial interface
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