XB24-BPDK Digi International/Maxstream, XB24-BPDK Datasheet - Page 55

• Manufacturer Part Number: XB24-BPDK
• Description: KIT DEVELOPMENT XBEE SERIES 2
• Manufacturer: Digi International/Maxstream
• Series: XBee™r
• Type: 802.15.4/Zigbeer

Specifications of XB24-BPDK

• Frequency: 2.4GHz
• For Use With/related Products: XBee™ Series 2 Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6. API Operation
6.0.1. API Frame Specifications
API Operation (AP parameter = 1)
API Operation - with Escape Characters (AP parameter = 2)
Start Delimiter
Start Delimiter
As an alternative to Transparent Operation, API (Application Programming Interface) Operations
are available. API operation requires that communication with the module be done through a
structured interface (data is communicated in frames in a defined order). The API specifies how
commands, command responses and module status messages are sent and received from the
module using a UART Data Frame.
Please note that Digi may add new API frames to future versions of firmware, so please build into
your software interface the ability to filter out additional API frames with unknown API identifiers.
Two API modes are supported and both can be enabled using the AP (API Enable) command. Use
the following AP parameter values to configure the module to operate in a particular mode:
When this API mode is enabled (AP = 1), the UART data frame structure is defined as follows:
Figure 6‐01. UART Data Frame Structure:
Any data received prior to the start delimiter is silently discarded. If the frame is not received
correctly or if the checksum fails, the module will reply with a module status frame indicating the
nature of the failure.
When this API mode is enabled (AP = 2), the UART data frame structure is defined as follows:
Figure 6‐02. UART Data Frame Structure ‐ with escape control characters:
Escape characters. When sending or receiving a UART data frame, specific data values must be
escaped (flagged) so they do not interfere with the data frame sequencing. To escape an
interfering data byte, insert 0x7D and follow it with the byte to be escaped XOR’d with 0x20.
(Byte 1)
(Byte 1)
0x7E
0x7E
© 2008 Digi International, Inc.
• AP = 1: API Operation
• AP = 2: API Operation (with escaped characters)
MSB = Most Significant Byte, LSB = Least Significant Byte
MSB = Most Significant Byte, LSB = Least Significant Byte
MSB
MSB
(Bytes 2-3)
(Bytes 2-3)
Length
Length
LSB
LSB
Characters Escaped If Needed
API-specific Structure
API-specific Structure
Frame Data
Frame Data
(Bytes 4-n)
(Bytes 4-n)
(Byte n + 1)
(Byte n + 1)
Checksum
Checksum
1 Byte
1 Byte
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