Hello, I need to synchronize some actions on arm and pru and therefore need the fastest way to read the ARM cycle counter into the PRU.
I basically want to match up the PRU cycle counter and the ARM cycle counter. Am I right when I assume the ARM cycle counter runs exactly (PLL phase locked) 5 times faster than the PRU's? So I want to catch some GPIO event (gps pps) on the PRU and tell the ARM core in a scale of a few nanoseconds when it occured on his time scale. When ignoring overflowing 32 bit counters my pseudocode would be: 1) PRU waits in the initialization process to receive the ARM cycle counter 2) Write ARM cycle counter into PRU-DRAM 3) PRU sets his own counter to this value divided by 5 (+2 for the ram read and register write) 4) PRU waits for GPIO event 5) On GPIO event save own counter state, multiply by 5 and message it to ARM 6) ARM compares his cycle counter to the messaged one and knows when the GPIO event occured Any thoughts how to improve? Thanks, Steve -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
