Communications ASDA-B2-F
8-12 September, 2015
8
CRC (RTU Mode):
The calculation description of CRC value is as the followings:
1. Load a 16-bit register of FFFFH, which is called ‟CRC” register.
2. (The low byte of CRC register) XOR (The first byte of command), and save the result to CRC
register.
3. Check the least significant bit (LSB) of CRC register. If the bit is 0, right move one bit; If the
bit is 1, then right move one bit and (CRC register) XOR (A001H).
4. Return to step 3 until step 3 has been executed for 8 times. Go to step 5.
5. Repeat the procedure from step 2 to step 4 until all byte is processed.
The content of CRC register is the CRC value.
After calculating the CRC value, fill in the low word of CRC value in command message, and
then the high word. For example, if the result of CRC calculation is 3794H, 94H should be filled in
low word and 37H in high word which is shown as below:
ARD 01H
CMD 03H
Start Data Address
01H (High)
01H (Low)
Data Number
(in word)
00H (High)
02H (Low)
CRC Check Low 94H (Low)
CRC Check High 37H (High)
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