Cortex-A vs. Cortex-M, Real Time Applications

I'm searching for microcontrollers for a real-time motor control application. I see a lot of Cortex-M solutions for handling this, but why don't we see a lot of Cortex-A solutions specifically targeted for this?

Is there something inherent to the Cortex-A that makes it inappropriate for hard real-time applications? I'm also aware of the Cortex-R, but there aren't as many vendors providing solutions using this core.

  • Hello,

    the real time needs the definite processing time. However, when we use Cortex-A, the processing time will vary according to the miss of caches or TLBs. Therefore, it is commonly said that program should be run on TCM (i.e. Tightly Coupled Memory) to ensure the definite processing time. As Cortex-M or Cortex-R has TCMs, it will be suitable for the real time.
    I think that RZ/T1 from Renesas Electronics would be the most suitable for the motor control. The CPU of RZ/T1 is Cortex-R4 of which speed is 600MHz.


    Best regards,
    Yasuhiko Koumoto.