SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
If DMA controller is available in a system the CRC module can also operate in semi-CPU mode. This means that CPU can still make use of the DMA to perform data patterns transfer to CRC controller in the background. The difference between semi-CPU mode and AUTO mode is that CRC controller does not automatically perform the signature verification. CRC controllers generates a compression complete interrupt to CPU when the one sector of data patterns are compressed. CPU needs to perform the signature verification itself.
A memory area with 2 Mbytes is to be verified with the help of the CPU. CRC operation is to be performed every 1 Kbyte. Since there are 2 Mbytes (256 K doublewords) of memory to be check and we want to perform a CRC every 1 Kbytes (128 doublewords) and therefore there must be 2048 pre-recorded CRC values. In Semi-CPU mode, the MCRC64_0_CRC_REGL1/H1 is not updated and contains indeterminate data.