SPRUIM2H May 2020 – October 2023 AM2431 , AM2432 , AM2434 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442
After one sector of data is compressed, the final resulting signature calculated by PSA Signature Register is transferred to the 64-bit PSA Sector Signature Register (MCRC_PSA_SECSIGREGL1-4 and MCRC_PSA_SECSIGREGH1-4). PSA Signature Register is a read-only register. During Semi-CPU mode, the host CPU must read from the PSA Sector Signature Register instead of reading from PSA Signature Register for signature verification to avoid data coherency issue. The PSA Signature Register can be updated with new signature before the host CPU is able to retrieve it.
In Semi-CPU mode, no DMA request is generated. When one sector of data patterns is compressed, CRC controller first generates a compression complete interrupt. Responding to the interrupt, CPU will read the PSA Sector Signature Register and compare it to the known good signature or write the signature value to another memory location to build a signature file. In Semi-CPU mode, CPU must perform the signature verification in a manner to prevent any overrun condition. The overrun condition occurs when the compression complete interrupt is generated after one sector of data patterns is compressed and CPU has not read from the PSA Sector Signature Register to perform necessary signature verification before PSA Sector Signature Register is overridden with a new value. An overrun interrupt can be enabled to generate when overrun condition occurs.