Tool/software:
We're working on an industrial safety critical product and have chosen this processor. Our strategy is to use the M4 to meet all of our functional safety requirements. It seems to have the necessary peripherals--GPIO, a UART, and SPI. We believe the M4 core to have plenty of performances to meet our needs. I believe the DMA controller cannot be used which is disappointing but not required. An important consideration is that we will pay a significant amount to certify SafeRTOS on this core. We're using Linux on the A53 cores to perform all other tasks, to have access to a filesystem, and make use of networking.
Our interprocessor communication strategy is to use the 2 MB of MSRAM and make use of the firewall to make some memory read-only and write-only between the A53s and the M4. For example message mailboxes and a ring buffer that is read-only from Linux to pull data collected via the M4 UART.
Are we using this part in a way that it is not designed to be used? Should the M4 only be used for the error signal monitor and the R5 for our logic that will make the system safe? Are there any performance differences (we've been told performance between the M4 and DDR is quite poor)?
Thanks for reading.