XBP24-PKI-001-RA Digi International/Maxstream, XBP24-PKI-001-RA Datasheet - Page 11

• Manufacturer Part Number: XBP24-PKI-001-RA
• Description: MODULE 802.15.4 RS-232 ANT
• Manufacturer: Digi International/Maxstream
• Series: XBEE-PRO™r

Specifications of XBP24-PKI-001-RA

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4
• Applications: Home/Building Automation, Industrial Control, ZigBee™
• Power - Output: 0dBm
• Sensitivity: -92dBm
• Voltage - Supply: 2.8 V ~ 3.4 V
• Current - Receiving: 55mA
• Data Interface: Connector, Female DB-9
• Antenna Connector: RP-SMA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Memory Size: -
• Current - Transmitting: -
• Other names: Q3255595

© 2008 Digi International, Inc.
XBee‐PRO PKG‐R® RS‐232 RF Modem – 802.15.4 ‐ Product Manual v1.xAx
3.1.5. Flow Control
DI (Data In) Buffer
DO (Data Out) Buffer
Figure 3‐02. Internal Data Flow Diagram
When serial data enters the RF modem through the DI (Data In) pin, the data is stored in the DI
Buffer until it can be processed.
Hardware Flow Control (CTS). When the DI buffer is 17 bytes away from being full; by default,
the modem de-asserts CTS (high) to signal to the host device to stop sending data [refer to D7
(DIO7 Configuration) parameter]. CTS is re-asserted after the DI Buffer has 34 bytes of memory
available.
How to eliminate the need for flow control:
Case in which the DI Buffer may become full and possibly overflow:
Refer to the RO (Packetization Timeout), BD (Interface Data Rate) and D7 (DIO7 Configuration) com-
mand descriptions for more information.
Refer to the BD (Interface Data Rate) [p34] and RO (Packetization Timeout) [p46] command descrip-
tions for more information.
When RF data is received, the data enters the DO buffer and is sent out the serial port to a host
device. Once the DO Buffer reaches capacity, any additional incoming RF data is lost.
Hardware Flow Control (RTS). If RTS is enabled for flow control (D6 (DIO6 Configuration)
Parameter = 1), data will not be sent out the DO Buffer as long as RTS (DIO6) is de-asserted.
Two cases in which the DO Buffer may become full and possibly overflow:
To implement API operations, refer to API sections [p50].
1.
2.
If the modem is receiving a continuous stream of RF data, any serial data that arrives on the DI
pin is placed in the DI Buffer. The data in the DI buffer will be transmitted over-the-air when the
modem is no longer receiving RF data in the network.
1.
2.
Send messages that are smaller than the DI buffer size.
Interface at a lower baud rate [BD (Interface Data Rate) parameter] than the throughput
data rate.
receive data from the transmitting modem faster than it can send the data to the host.
being held off by hardware or software flow control.
If the RF data rate is set higher than the interface data rate of the modem, the modem will
If the host does not allow the modem to transmit data out from the DO buffer because of
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