XBP24-DMWIT-250 Digi International, XBP24-DMWIT-250 Datasheet - Page 11

• Manufacturer Part Number: XBP24-DMWIT-250
• Description: XBEE-PRO MESH 2.4 EXTENDED
• Manufacturer: Digi International
• Series: XBEE-PRO™r

Specifications of XBP24-DMWIT-250

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: ISM
• Applications: General Purpose
• Power - Output: 18dBm
• Sensitivity: -100dBm
• Voltage - Supply: 2.8 V ~ 3.4 V
• Current - Receiving: 55mA
• Current - Transmitting: 250mA
• Data Interface: PCB, Through Hole
• Antenna Connector: On-Board, Wire Whip
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: Q4542387

XBee/XBee‐PRO DigiMesh 2.4 RF Modules
GND
CTS
VCC
DOUT
RTS
DIN
Serial Flow Control
The RTS and CTS module pins can be used to provide RTS and/or CTS flow control. CTS flow control provides an indica-
tion to the host to stop sending serial data to the module. RTS flow control allows the host to signal the module to not send
data in the serial transmit buffer out the UART. RTS and CTS flow control are enabled using the D6 and D7 commands.
When serial data enters the RF module through the DIN Pin (pin 3), the data is stored in the serial receive buffer
until it can be processed. Under certain conditions, the module may not be able to process data in the serial receive
buffer immediately. If large amounts of serial data are sent to the module, CTS flow control may be required to avoid
overflowing the serial receive buffer.
1.
2.
When RF data is received, the data is moved into the serial transmit buffer and is sent out the serial port. If the
serial transmit buffer becomes full enough such that all data in a received RF packet won’t fit in the serial transmit
buffer, the entire RF data packet is dropped.
1.
2.
If CTS flow control is enabled (D7 command), when the serial receive buffer is is filled with FT bytes, the module
de-asserts CTS (sets it high) to signal to the host device to stop sending serial data. CTS is re-asserted when less
than FT - 16 bytes are in the UART receive buffer.
If flow RTS control is enabled (D6 command), data in the serial transmit buffer will not be sent out the DOUT pin as
long as RTS is de-asserted (set high). The host device should not de-assert RTS for long periods of time to avoid
filling the serial transmit buffer. If an RF data packet is received, and the serial transmit buffer does not have enough
space for all of the data bytes, the entire RF data packet will be discarded.
Serial Receive Buffer
Serial Transmit Buffer
CTS Flow Control
RTS Flow Control
transmitted until the module is no longer receiving RF data.
establish a route to the destination. After transmitting the data, the module may need to retransmit the data if
an acknowledgment is not received, or if the transmission is a broadcast. These issues could delay the process-
ing of data in the serial receive buffer.
than it can send the data to the host.
off by hardware flow control.
If the RF data rate is set higher than the interface data rate of the module, the module could receive data faster
If the host does not allow the module to transmit data out from the serial transmit buffer because of being held
If the module is receiving a continuous stream of RF data, the data in the serial receive buffer will not be
If the module is transmitting an RF data packet, the module may need to discover the destination address or
Serial Transmit
Receiver
Internal Data Flow Diagram
Cases in which the serial receive buffer may become full and possibly overflow:
Cases in which the serial transmit buffer may become full, resulting in dropped RF packets:
Buffer
Serial
Buffer
© 2010 Digi International, Inc.
Processor
RF RX
Buffer
RF TX
Buffer
Transmitter
Receiver
RF Switch
Antenna
Port
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