Digi XBee, Руководство пользователя, Страница: 44 / 307

Operation Break control
XBee/XBee-PRO® S2C ZigBee® RF Module 44
If the device sends data out the UART when RTS is de-asserted (set high) the device could send up to
five characters out the UART port after RTS is de-asserted.
Break control
If a serial break (DIN held low) signal is sent for over five seconds, the device resets, and it boots into
Command mode with default baud settings (9600 baud). If either
P3 or P4 are not enabled, this break
function is disabled.
Serial interface protocols
The XBee/XBee-PRO ZigBee RF Module supports both Transparent and Application Programming
Interface (API) serial interfaces.
Transparent operating mode
When operating in Transparent mode, the devices act as a serial line replacement. The device queues
up all UART or SPI data received through the DIN or MOSI pin for RF transmission. When RF data is
received, the device sends the data out through the serial port. Use the Command mode interface to
configure the device configuration parameters.
Note Transparent operation is not available when using SPI.
The device buffers data in the serial receive buffer and packetizes and transmits the data when it
receives the following:
n
No serial characters for the amount of time determined by the RO (Packetization Timeout)
parameter. If RO = 0, packetization begins when the device received a character.
n
Command Mode Sequence ( GT + CC + GT ). Any character buffered in the serial receive buffer
before the device transmits the sequence.
n
Maximum number of characters that fit in an RF packet.
API operating mode
API operating mode is an alternative to Transparent operating mode. The frame-based API extends
the level to which a host application can interact with the networking capabilities of the device. When
in API mode, the device contains all data entering and leaving in frames that define operations or
events within the device.
The API provides alternative means of configuring devices and routing data at the host application
layer. A host application can send data frames to the device that contain address and payload
information instead of using Command mode to modify addresses. The device sends data frames to
the application containing status packets, as well as source and payload information from received
data packets.
The API operation option facilitates many operations such as:
n
Transmitting data to multiple destinations without entering Command Mode
n
Receive success/failure status of each transmitted RF packet
n
Identify the source address of each received packet