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TMDX570LC43HDK: Minimum FreeRTOS tick configurable on TMDX570LC43HDK

Etantonio
Intellectual 920 points
Part Number: TMDX570LC43HDK

Hy,

I'm interested to create variable delays at runtime using timers in FreeRTOS,

the delays are in the order of 10microseconds or more,

the timers could be delayed of multiple of the tick,

so my question is, can TMDX570LC43HDK support a tick of 1microsecond,

or in a different way, what is the minimum tick configurable on this board?

Thanks

Antonio

  • 0
    TI__Guru 59540 points
    Hello Antonio,

    I am not an expert in Free RTOS, but I believe that the system tick is a product of the RTI module. It is capable of generating the system tick based on your chosen clock source for the RTICLK. This can be any of the clock domains in the device including OSCIN, HF/LF LPO, HCLK, or VCLK. If you choose VCLK and you are running your peripheral clock at 110MHz, you could theoretically generate the systick every 9.1pSecs (although not advisable). The issue then becomes latency due to processing of the systick timer because this becomes an interrupt and consumes a great deal of CPU bandwidth to maintain this tick timer. I think you may have the same issue with a 1uSec tick time as well. Unfortunately, I don't have a really good answer on what the point of saturation will be on this. I would suggest some characterization on CPU utilization to identify the most optimum systick for your system needs. Also note that you would/should identify the systick interrupt as the highest priority you can so that jitter is minimized as other interrupts and exceptions may interfere with accurate timebase needs.
  • 0 in reply to Chuck Davenport
    Intellectual 920 points
    Thanks Chuck for your reply,
    so a good starting point could be a 110MHz VCLK clock,
    1ms tick to avoid too busy cpu,
    and to obtain sporadic variable delays in the order of multiples of 50uS I was thinking to N2Het,
    it is a coprocessor so no extra effort for the CPU but I'm not sure about the fact that it could be programmed to obtain a variable delay in the order of multiple of 50uS and expecially that it is possible to change the delay at runtime.
    Antonio