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RTOS/MSP432P401R: Handle TickPeriod changes when the clock source changes

Kevin Cutts7
Intellectual 260 points

Part Number: MSP432P401R

Tool/software: TI-RTOS

I'm using the TI-RTOS example from the resource explorer on the Launchpad. The RTOS is up and running. Now I'm trying to modify the ACLK using 

MAP_CS_initClockSignal(CS_ACLK, CS_REFOCLK_SELECT, CS_CLOCK_DIVIDER_2);

in the main function and with this config, the tick count is off by a factor of two (Task_sleep(500) takes twice as long) . Which tells me that the tick counter has decided to source off the ACLK and the default divider for ACLK must have been 1.

What is the proper way to adjust the ACLK so that the built in tick count gets adjusted?

  • 0
    TI__Mastermind 22580 points
    Hello Kevin,

    I have asked my colleague who has more knowledge on this topic to look into this question.

    Thanks,
    Sai
  • 0 in reply to Sai Reddy
    TI__Mastermind 22580 points
    Hello Kevin,

    Wanted to update that my colleague is on vacation till middle of next week. Let me know if you need this resolved sooner than that.

    Thanks,
    Sai
  • 0 in reply to Sai Reddy
    Intellectual 260 points

    That will work.

  • 0 in reply to Kevin Cutts7
    TI__Guru 58551 points

    Hello,

        I have tried to use the ClockFreqs_setFrequency and the Clock_tickReconfig APIs without success.  I do not believe there is a mechanism to update the clock frequency for the MSP432.  The default configuration for the tick is to use TIMER_A0 in continuous mode being sourced from ACLK.  What are you trying to accomplish?  Would it be possible to setup another clock object to achieve the desired timing without adjusting ACLK?


    Regards,

    Chris

  • 0 in reply to Chris Sterzik
    Intellectual 260 points

    I'm trying to change the ACLK to a lower frequency for another use in my project. But doing so has a side effect of making the timeouts for many of the RTOS functions wrong (i.e. sleep(500) is no longer a 500 tick delay, its 1000 ticks, mailbox_pend(x,y,20) is no longer a 20 tick delay). 

    I guess the only solution is to set the tick count value in the RTOS too 500usec so when I drop the ACLK, the tick count will be 1000usec. But its a sloppy solution and I was hoping for more. Does everyone just use the default ACLK value?

  • 0 in reply to Kevin Cutts7
    TI__Guru 58551 points

    Hello,

        An alternative would be to change the performance level, which includes the clock settings.  The intent of this discussion was to demonstrate power consumption but can also be used to manipulate the ACLK.

    Regards,

    Chris

  • 0 in reply to Chris Sterzik
    TI__Guru 58551 points

    I am going to close this.  Please use 'Ask a related question' for further inquiries.

    Regards,
    Chris

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