
API Operation
Data bytes that need to be escaped:
XBee/XBee-PRO® S2C ZigBee® RF Module
153
API frame names
API ID
ZigBee Transmit Request
0x10
Explicit Addressing ZigBee Command Frame
0x11
Remote Command Request
0x17
Create Source Route
0x21
AT Command Response
0x88
Modem Status
0x8A
ZigBee Transmit Status
0x8B
ZigBee Receive Packet (AO=0)
0x90
ZigBee Explicit Rx Indicator (AO=1)
0x91
ZigBee I/O Data Sample Rx Indicator
0x92
XBee Sensor Read Indicator (AO=0)
0x94
Node Identification Indicator (AO=0)
0x95
Remote Command Response
0x97
Extended Modem Status
0x98
Over-the-Air Firmware Update Status
0xA0
Route Record Indicator
0xA1
Many-to-One Route Request Indicator
0xA3
Calculate and verify checksums
To test data integrity, the device calculates and verifies a checksum on non-escaped data.
To calculate the checksum of an API frame:
1. Add all bytes of the packet, except the start delimiter 0x7E and the length (the second and
third bytes).
2. Keep only the lowest 8 bits from the result.
3. Subtract this quantity from 0xFF.
To verify the checksum of an API frame:
1. Add all bytes including the checksum; do not include the delimiter and length.
2. If the checksum is correct, the last two digits on the far right of the sum equal 0xFF.
Example
Consider the following sample data packet:
7E 00 0A 01 01 50 01 00 48 65 6C 6C 6F B8