To Next Page

To Previous Page

XBee® Wi-Fi RF Modules

Modes of Operation

Idle Mode

When not receiving or transmitting data, the RF module is in Idle Mode. The module

shifts into the other modes of operation under the following conditions:

• Transmit Mode (Serial data in the serial receive buffer is ready to be packetized)

• Receive Mode (Valid RF data is received through the antenna)

• Sleep Mode

• Command Mode (Command Mode Sequence is issued)

Transmit Mode

When serial data is received and is ready to be packetized, the RF module will exit Idle

Mode and attempt to transmit the data. The destination address determines which

node(s) will receive the data.

Receive Mode

If a valid RF packet is received, the data is transferred to the serial transmit buffer.

Command Mode

To modify or read RF Module parameters, the module must first enter into Command

Mode - a state in which incoming serial characters are interpreted as commands. Refer

to the API Operation chapter for an alternate means of configuring modules, which is

the only method available for SPI mode. (Command mode is unavailable when using the

SPI interface.)

AT Command Mode

To Enter AT Command Mode:

Send the 3-character command sequence “+++” and observe guard times before and

after the command characters. [Refer to the “Default AT Command Mode Sequence”

below.]

Default AT Command Mode Sequence (for transition to Command Mode):

• No characters sent for one second [GT (Guard Times) parameter = 0x3E8]

• Input three plus characters (“+++”) within one second [CC (Command Sequence

Character) parameter = 0x2B.]

• No characters sent for one second [GT (Guard Times) parameter = 0x3E8]

Once the AT command mode sequence has been issued, the module sends an "OK\r"

out the UART. The "OK\r" characters can be delayed if the module has not finished

transmitting received serial data.

When command mode has been entered, the command mode timer is started (CT

command), and the module is able to receive AT commands on the UART.

All of the parameter values in the sequence can be modified to reflect user preferences.

Digi XBee Manual

Other manuals for Digi XBee