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Modes
Transparent operating mode
Digi XBee3 Cellular LTE-M/NB-IoT Global Smart Modem User Guide
122
Transparent operating mode
Devices operate in this mode by default. The device acts as a serial line replacement when it is in
Transparent operating mode. The device queues all serial data it receives through the DIN pin for RF
transmission. When a device receives RF data, it sends the data out through the DOUT pin. You can set
the configuration parameters using Command mode.
The
command setting controls how Transparent operating mode works for the XBee
Smart Modem.
Note
Transparent operation is not available when using SPI.
API operating mode
API operating mode is an alternative to Transparent operating mode. API mode is a frame-based
protocol that allows you to direct data on a packet basis. The device communicates UART or SPI data
in packets, also known as API frames. This mode allows for structured communications with
computers and microcontrollers.
The advantages of API operating mode include:
n
It is easier to send information to multiple destinations
n
The host receives the source address for each received data frame
n
You can change parameters without entering Command mode
Command mode
Command mode is a state in which the firmware interprets incoming characters as commands. It
allows you to modify the device’s configuration using parameters you can set using AT
commands. When you want to read or set any parameter of the XBee Smart Modem using this mode,
you have to send an AT command. Every AT command starts with the letters
AT
followed by the two
characters that identify the command and then by some optional configuration values.
The operating modes of the XBee Smart Modem are controlled by the
setting,
but Command mode is always available as a mode the device can enter while configured for any of the
operating modes.
Command mode is available on the UART interface for all operating modes. You cannot use the SPI
interface to enter Command mode.
Enter Command mode
To get a device to switch into Command mode, you must issue the following sequence:
+++
within one
second. There must be at least one second preceding and following the
+++
sequence. Both the
command character (
CC
) and the silence before and after the sequence (
GT
) are configurable. When
the entrance criteria are met the device responds with
OK\r
on UART signifying that it has entered
Command mode successfully and is ready to start processing AT commands.
If configured to operate in
, when entering Command mode the XBee
Smart Modem knows to stop sending data and start accepting commands locally.
Note
Do not press
Return
or
Enter
after typing
+++
because it interrupts the guard time silence and
prevents you from entering Command mode.
When the device is in Command mode, it listens for user input and is able to receive AT commands on
the UART. If
CT
time (default is 10 seconds) passes without any user input, the device drops out of