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STM32F4 FreeRTOS and us accuracy delay

Question asked by desaissement.benoit on Nov 13, 2013
Latest reply on Nov 15, 2013 by desaissement.benoit
Hi everyone,

I'm currently working on a musical (using midi) project on which i need very precise delay in order to synchronise with other instruments. This delay should be able to be accurate at 1 microsecond.

For instance, i have "overclocked" FreeRTOS increasing configTICK_RATE_HZ from 1000 to 1000000. And i have a cylclic task (using vTaskDelayUntil()) trigerred each 5208 microseconds (for 120 beats per minute).

Obviously increasing configTICK_RATE_HZ is not a good idea and anyway i don't get the accuracy i wanted. If i synchronise with another instrument for a BPM of 120 i get approximatively 119,80.

For you what is the best way to get such accuracy ? Using an hardware timer and trigger interrupts ? Is it really impossible to run correctly FreeRTOS at this tick rate..?