CODEWITHSUNDEEP
armcortex-r
David Monniaux
David Monniaux

Reputation: 2004

64-bit cycle counter on Cortex-R5

By configuring the PMU of the Cortex-R5 it's possible to get a cycle count. However the counter is 32-bit, which means it wraps after some seconds. Is there a way to get or emulate a 64-bit counter?

Upvotes: 0

Views: 310

Answers (1)

solidpixel
solidpixel

Reputation: 12169

Option 1 - Set PMCR.D to 1 and count every 64 cycles, to trade accuracy for range, which effectively gives you a 38-bit counter.

Option 2 - Set up PMINTENSET to raise an interrupt on a 32-bit overflow and write a small driver to accumulate into a 64-bit value in software. This relies on the PMU IRQ being wired up to the interrupt controller; it normally is but isn't guaranteed.

Upvotes: 1

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