concerto VCU: CRC P1 functionality

Nolwenn Jarossay

Other Parts Discussed in Thread: CONTROLSUITE

Dear All,

I currently perform some tests with the Concerto F28M35H52C1 VCU. I would like to calculate a 16 bits CRC, using 0x8005 polynomial.

I tried some simple CRC16 "IBM" test vectors, using the P1 instructions set; unfortunately the results did not match.

If a pattern with 0xFFFFFFFF input value is used, we can notice a bits order inversion with the IBM standard.

In the control SUITE example, the name of this CRC is "CRC16_ALT". Is it possible to have some additional information about this type of CRC16? And/or is there any fast algorithm, that could ensure the compatibility with the IBM CRC16 standard?

Thank you,

Nolwenn

over 14 years ago

0 Vishal_Coelho over 14 years ago

TI__Mastermind 20850 points

Hi Nolwenn,

Did you use the source code from the VCU library in controlSUITE ? I would also try to use the linker generated CRC using the polynomial 0x8005 as a comparison point. All compilers 6.0.1 and above have this ability and it is described in the Assembler user guide (SPRU513D)

0 Nolwenn Jarossay over 14 years ago in reply to Vishal_Coelho

Prodigy 90 points

Dear Vishal,

Yes I used the source code from the VCU library, and thanks to your advice I could find a "cpu" CRC function and understood how it works. I think the CRC16 "alt" has the same algorithm than CCITT; the only difference is the polynomial.

Thank you again,

Nolwenn

0 Keyur Acharya over 13 years ago in reply to Nolwenn Jarossay

Expert 1740 points

try giving data in a reflected manner (bit by bit) and you will be getting the answer in reflected form.
this happens as the modbus protocol is reversed and reflected algorithm.
i wonder why TI has not implemented it directly in hardware....

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concerto VCU: CRC P1 functionality