Periodic timer (64Hz) with ARM processor and (embedded) Linux

Question

I want to call a function 64 times per second with a ARM processor which is running linux. (ex: Rasberry Pi or Freescale i.mx6).

Ideally, I don't want too much jitter. I want to perform a task periodically... (ie: scanning a device)

If possible, I would like a hardware interrupt called 64 times per second.

With "standard PC hardware (x86)", it was possible to use IRQ8 from the RTC (clock) to achieve that behavior.

What is the equivalent with ARM processor architecture?

Reference 1, See section "Old "RTC Class" Drivers"

Reference 2

Answer 1

I would think a Watchdog timer would work in this situation. When the timer reaches 0 or it overflows (it depends on if it counts down or up) the processor will trigger an interrupt. If you configure the timer properly it might be able to trigger at 64Hz but that depends on the pre- and postscalers. It looks like the ARM processor does have such capabilities.

Answer 2

You could always create a real-time thread (assuming your kernel has been compiled with realtime support), and have an infinite loop that uses nanosleep to get the desired 64Hz sample frequency.

How strict is your jitter requirement exactly?