AnsweredAssumed Answered

PWM max frequency

Question asked by Martin Dusek on May 16, 2018
Latest reply on May 16, 2018 by Mark Butcher

What is max. achievable edge aligned PWM (or any other PWM or output compare) frequency on Kinetis K22 in high speed run mode (MCGOUT = 120 MHz), all clocks set to max: CLKDIV1 = 0x01340000U (=> core/system = 120 MHz, bus = 60 MHz)?

 

As FTM is clocked by system clock I would assume 60 MHz is achievable. However, I'm able to generate only 30 MHz with this setting:

 

CLOCK_EnableClock(kCLOCK_Ftm0);
FTM0->SC = FTM_SC_CLKS(1);
FTM0->MOD = 1;
FTM0->CONTROLS[1].CnSC = FTM_CnSC_ELSB_MASK | FTM_CnSC_MSB_MASK;
FTM0->CONTROLS[1].CnV = 1;

 

I need to generate 1:2 high:low pulses with max. frequency.

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