Delta AH500 Programming Manual page 583

Step 4: If the value of the right-most bit which is shifted to the right is 0, the data gotten from
step 3 is stored in the 16-bit register. Otherwise, the logical operator XOR takes
16#A001 and the data in the 16-bit register, and performs the logical exclusive OR
operation on each pair of corresponding bits. The operation result is stored in the
16-bit register.
Step 5: Repeat step 3 and step 4, and perform the operation on the 8-bit message.
Step 6: Repeat step 2~step 5, and get the next 8-bit message. Perform the operations on all
messages. The final result in the 16-bit register is the CRC check code. Notice that
the low 8-bit data in the 16-bit register is interchanged with the high 8-bit data in the
16-bit register before the CRC check code is put into the check code of the message
C ha pt er 6 A p pl i e d In s tr uc t io n
6 - 4 1 5