RM57L843: CRC pattern length

Ravi Teja Darbha

Part Number: RM57L843

Tool/software:

Hi,

I am trying to use CRC on RM57. The structure passed to crcSignGen has "src_data_pat" whhich is a pointer to a buffer with 64 bit data buffer and another field is "data_length" which is number of 64 bit sized words in src_data_pat. However, if say I only have 5 bytes of data, what shoukd each of these values be?

Also, I tried the following code with a 64 bit data and I am getting wrong CRC value. Could you any tell me if I am missing something? I have configured this in FULL_CPU mode and using CRC1 and channel 0.

crcModConfig_t param;
uint64_t data = 0x4142434445464748;

void main()

{

crcInit();

crcChannelReset(crcREG1, 0);
param.crc_channel = 0;
param.mode = CRC_FULL_CPU;
param.data_length = 1;
param.src_data_pat = &data;
crcSignGen(crcREG1, &param);
sig = crcGetSectorSig(crcREG1, 0);

}

The value I am getting is 0xB19C8742DDF0EBAA whereas the correct value is 0x38178634E55140F2.

Thanks,

Ravi

6 months ago

0 jagadish gundavarapu 6 months ago

TI__Guru 62590 points

Hi Ravi,

Please refer my below FAQ:

(+) [FAQ] TMS570LC4357: Listing out the bugs in the Cyclic Redundancy Check (CRC) Controller Module - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

Here I listed the bugs in the driver code related to both big endian and little-endian devices.

As RM57x is a little-endian device, so please refer bug related to the little-endian device in above FAQ.

At the end of the FAQ, i also attached reference example. So, please refer it once.

--
Thanks & regards,
Jagadish.

0 Ravi Teja Darbha 6 months ago in reply to jagadish gundavarapu

Intellectual 305 points

Hi Jagadish,

I tried the CRC_FULL_CPU_MODE_RM57 code from your link above. In this I modified this to calculate CRC of a single 64 bit data instead of 128 x 64 bit data. I then compared the calculated CRC with the CRC-64 ISO calculated from this website. However, I still cannot get it to match. The wesite uses the same CRC polynomial mentioned in the RM57 reference manual. Can you take a look?

https://www.lddgo.net/en/encrypt/crc

Thanks,

Ravi

0 jagadish gundavarapu 6 months ago in reply to Ravi Teja Darbha

TI__Guru 62590 points

Hi Ravi,

You should not use CRC-64 ISO because there is a slight change for our algorithm from CRC-64 ISO

If we keep CRC-64 ISO then it is taking initial and XOROUT values as 0xFFFFFFFFFFFFFFFF right?

But for our calculations we should make the above values as 0x0000000000000000, so keep the custom and make the changes as below:

As you can see for your data 0x4142434445464748, i got the compressed CRC as 0xDDF0EBAAB19C8742 from website and here is the compressed CRC from the CRC module:

As you can see both are matching.

--
Thanks & regards,
Jagadish.