CRC CALCULATION OF L9963E

[ratan22]

I’m working on the SPI communication between a microcontroller and the L9963E.
The datasheet of the L9963E shows little information about the CRC calculation,
but mentions:

• a CRC of 6 bits,
• a polynomial of X6 + X4 + X3 + 1 = 0b1011001
• a seed of 0b111000

The documentation also mentions in the SPI protocol details that the CRC is a value between 0x00 and 0x3F, and is "calculated on the [39-7] field of the frame", see Table 22.

Total data bit length is 40bit(39-0) out of this 6bits are CRC(5-0) and data bit is 34bit(39-7).

Some examples are

• Data=C004000021, CRC=21
• Data=C004000078, CRC=38
• Data=C004000093, CRC=13
• Data=C0040000CA, CRC=A

We are not able to find how CRC is coming out of the above data.

 

[ads-ee]

The tables 27 and 28 on page 35 shows that the LSB of the data is located at bit-6. I think the 39-7 in table 29 on page 35 is a typo. I think a tech writer was think crc is 6-bits so the rest of the bits are in 7 and up.

I would first try doing the crc calculation over 39-6, if that doesn't work try 38-6, and possibly 37-6 as that leaves out both P.A. and RW.

 

[ratan22]

Thank u for your suggestion.
we went by your process but did not get correct result.