Api Frames - Digi XBee-PRO 900 Instruction Manual

XBee‐PRO® 900 OEM RF Modules
API Frame Names and Values
API Frame Names Values
Modem Status
AT Command
AT Command - Queue
Parameter Value
AT Command Response
Remote Command Request
Remote Command
Response
Transmit
Request
Explicit Addressing
Command
Frame
Transmit
Status
Receive
Packet (AO=0)
Explicit Rx
Indicator (AO=1)
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Data bytes that need to be escaped:
• 0x7E – Frame Delimiter
• 0x7D – Escape
• 0x11 – XON
• 0x13 – XOFF
Example - Raw UART Data Frame (before escaping interfering bytes):
0x7E 0x00 0x02 0x23 0x11 0xCB
0x11 needs to be escaped which results in the following frame:
0x7E 0x00 0x02 0x23 0x7D 0x31 0xCB
Note: In the above example, the length of the raw data (excluding the checksum) is 0x0002 and
the checksum of the non-escaped data (excluding frame delimiter and length) is calculated as:
0xFF - (0x23 + 0x11) = (0xFF - 0x34) = 0xCB.
Checksum
To test data integrity, a checksum is calculated and verified on non-escaped data.
To calculate: Not including frame delimiters and length, add all bytes keeping only the lowest 8
bits of the result and subtract the result from 0xFF.
To verify: Add all bytes (include checksum, but not the delimiter and length). If the checksum is
correct, the sum will equal 0xFF.

API Frames

Frame data of the UART data frame forms an API-specific structure as follows:
UART Data Frame & API‐specific Structure:
Start Delimiter Length
(Byte 1) (Bytes 2-3)
MSB
0x7E
The cmdID frame (API-identifier) indicates which API messages will be contained in the cmdData
frame (Identifier-specific data). Note that multi-byte values are sent big endian. The modules
support the following API frames:
© 2008 Digi International, Inc.
Frame Data
(Bytes 4-n)
LSB API-specific Structure
API Identifier Identifier-specific Data
cmdID
0x8A
0x08
0x09
0x88
0x17
0x97
0x10
0x11
0x8B
0x90
0x91
Checksum
(Byte n + 1)
1 Byte
cmdData
26