Operate in API mode Calculate and verify checksums
XBee®-PRO 900HP/XSC RF Modules
120
7E 00 0A 01 01 50 01 00 48 65 6C 6C 6F B8
Add these hex bytes:
01 + 01 + 50 + 01 + 00 + 48 + 65 + 6C + 6C + 6F = 247
Now take the result of 0x247 and keep only the lowest 8 bits which in this example is 0x47 (the two
far right digits). Subtract 0x47 from 0xFF and you get 0xB8 (0xFF - 0x47 = 0xB8). 0xB8 is the checksum
for this data packet.
If an API data packet is composed with an incorrect checksum, the XBee-PRO 900HP RF Module will
consider the packet invalid and will ignore the data.
To verify the check sum of an API packet add all bytes including the checksum (do not include the
delimiter and length) and if correct, the last two far right digits of the sum will equal FF.
01 + 01 + 50 + 01 + 00 + 48 + 65 + 6C + 6C + 6F + B8 = 2FF
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