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TMS570 TRM discrepancy and RTI question

Eugene K
Expert 1685 points

1. It looks like there is a typo in TRM (spnu489a) on page 1581 (21.2.1 Counter Operation). Should FRTIFRCx=FRTICLK/232  when when RTICPUCx = 0 instead of the formula presented there?

2. What would be the tCOMPx when RTIUDCPy=0? The formula on page 1582 suggest that it would be 0.

Thank you,

Eugene

  • 0
    TI__Prodigy 365 points

    Hi Eugen,

    Ans 1 :- Yes it looks like a typo error, i have updated the module owner regarding this and if confirmed it will be rectified in the next revision

    Ans 2 :-  The first interrupt will be generated when Free running counter(FR0 or FR1) matches the RTI Compare Regsiter, in order to generate next/another interrupt the Free running counter should overflow and match the same RTI compare Register.     

                           Tcompx  = TRTICLK * (RTIUCPx+1) * RTIUDCP              when RTIUCPx  != 0 and RTIUDCP != 0

                           Tcompx  = TRTICLK * (232) * (232 + RTICOMPx)               when RTIUCPx  = 0 and RTIUDCP =  0

    Regards

    Hari

  • 0 in reply to Hari49672
    Expert 1685 points

    Hari,

    Doesn't  your second formula only apply to first interrupt interval? All consecutive interrupts will be periodic at Tcompx=TRTICLK*223*232.

    Thanks,

    Eugene


  • 0 in reply to Eugene K
    TI__Prodigy 365 points

    Hi Eugene,

    Yes you are right, The Point I was trying stress was the consecutive interrupts are generated when the Free running counter matches the RTI Compare Register,

    Please check the modified equation below.

    when RTIUCPx  = 0 and RTIUDCP =  0

    First Interrupt occurs at Tcompx = TRTICLK * (232) *  RTICOMPx           

    Consecutive Interrupt occurs at  Tcompx = TRTICLK * (232) *  (232) [The interrupt is generated at the point when FRCx = RTICOMPx]

    Let me know your observations

    Regards

    Hari