AM2634: [ AM263x ] Does MCRC module support 8-bit data size?

Orazio Taglialatela Scafati

Part Number: AM2634

Tool/software:

Dear all,

we are working on an MCRC-based implementation of the standard CRC32 algorithm (POLY 0x04C11DB7, INIT 0xFFFFFFFF, XOROUT 0xFFFFFFFF, REFIN, REFOUT as specified here: CRC Calculation Online (lddgo.net)). We would like to replicate the functioning and the numerical results of the software algorithm with the MCRC module of AM263x.

Our software implementation of CRC32 works on 8-bit data blocks, for which the CRC of the 8-bit "0" data is 0xD202EF8D, in accordance with the online tool above.

We are focusing on the FULLCPU mode, based on the example from the C:/ti/mcu_plus_sdk_am263x_10_00_00_35/docs/api_guide_am263x/SDL_MCRC_PAGE.html.

The issue is that, while we managed to get "good" results using the SDL_MCRC_DATALENGTH_32BIT and SDL_MCRC_DATALENGTH_16BIT values for the MCRC_CTRL0.CH1_DW_SEL register, the Register Addendum does not specify how to select 8-bit data size (although the source code appears to support it - cfr. SDL_MCRC_dataWrite() function and SDL_MCRC_DATA_8_BIT).

Question is: does the MCRC module support 8-bit data blocks for CRC32? And, if so, how can we enable it?

Thank you in advance.

Best regards.

Edit: rewording of issue, s/TRM/Register Addendum.

over 1 year ago

0 QJ Wang over 1 year ago

TI__Guru**** 197356 points

Hi Orazio,

The TRM says that the 8-bit is supported, but I don't find the bit field for 8-bit data size in Register Addendum. I will check the TRM owner.

0 Orazio Taglialatela Scafati over 1 year ago in reply to QJ Wang

Prodigy 30 points

Correct, I have amended the text. My apologies and look forward to your reply.

0 Orazio Taglialatela Scafati over 1 year ago in reply to QJ Wang

Prodigy 30 points

Hi QJ Wang

I was wondering if there's any update on this issue.

Thank you.

Kind regards.

0 QJ Wang 11 months ago in reply to Orazio Taglialatela Scafati

TI__Guru**** 197356 points

Hi Orazio,

Apologies for late response. 8-bit data pattern is supported although 8-bit data size is not included in the control register. I am not very clear how the MCRC uses this parameter during computing the CRC and counting the number of data pattern. In full-CPU mode, all the counters are disabled. In semi-CPU mode and Auto mode, the DMA is utilized to transfer data patterns (8-bit, 16-bit, ..) to PSA signature register and count the number of transfer. I haven't got a comment from the TRM owner.

0 Orazio Taglialatela Scafati 11 months ago in reply to QJ Wang

Prodigy 30 points

Hi QJ Wang

thanks for your reply.

I have noted that in in latest AM263x Sitara Microcontroller Errata (updated May 2024), the following item is reported:

i2386 CRC: CRC 8-bit data width and CRC8-SAE-J1850 and CRC8-H2F possible use in CAN module is not supported. Minimum data width supported is 16-bit.

That might be unrelated, but can you please give some insight on that issue and whether it is somehow linked to CRC32 calculation with MCRC?

Thank you.

Kind regards.

0 QJ Wang 11 months ago in reply to Orazio Taglialatela Scafati

TI__Guru**** 197356 points

Hi Orazio,

I2386 of errata means the CRC8 is not supported. I think that the data size (8-bit, 16-bit, ..) is different from the 8-bit CRC (check value is 8-bit).

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AM2634: [ AM263x ] Does MCRC module support 8-bit data size?