Clocking the MK20FX512 with Processor Expert?

simonhaines — Wed, 13 Jan 2016 04:23:12 GMT

I'm trying to clock a Kinetis MK20FX512 at 96MHz core clock speed and 48MHz bus speed with Processor Expert. I have a 32.768kHz crystal attached to XTAL32/EXTAL32 (with nothing on XTAL0/EXTAL0 and XTAL1/EXTAL1) and I am able to set the following configuration manually in code:

RTC OSCE 32.768 kHz oscillator is enabled
SIM OSC32KSEL RTC oscillator selected as 32kHz clock source (ERCLK32K)
SIM PLLFLLSEL MCGFLLCLK selected for various peripheral clocking options
SIM OUTDIV1 Sys: /1
SIM OUTDIV2 Bus: /2
OSC0 ERCLKEN External reference clock enabled
OSC1 ERCLKEN External reference clock enabled
MCG OSCSEL 32kHz RTC oscillator selected as FLL external reference clock
MCG RANGE0 Low frequency range selected for crystal oscillator
MCG HGO0 High gain oscillator configured for low-power operation
MCG EREFS0 External reference clock selected (not oscillator) as EREF source
MCG IRCS Slow internal reference clock selected (instead of fast IREF)
MCG CLKS Output of FLL selected as clock source
MCG FRDIV /1 divider for external reference clock (OSCSEL has reset value of 0)
MCG IREFS External reference clock selected as source for the FLL
MCG IRCLKEN Internal reference clock is enabled
MCG IREFSTEN Internal reference clock is disabled in stop mode
MCG DMX32 DRST_DRS DCO range is 96MHz

This produces the desired core clock speed of 96MHz and bus speed of 48MHz. Using processor expert, I can't select XTAL32/EXTAL32 as the clock source for the RTC (only RTC_CLKIN is available) or the DMX32 and DRST_DRS values to get the clock to 96MHz. The highest value seems to be 47.972352MHz. Is this a problem with my configuration or with Processor Expert?

Re: Clocking the MK20FX512 with Processor Expert?

Jorge_Gonzalez — Mon, 25 Jan 2016 18:03:41 GMT

Hello Simon Haines:

Please let us know the version of Processor Expert or the IDE version that you are using (Codewarrior or Kinetis Design Studio).

Are you sure you selected K20FX512 from the New Project Wizard?

This device does not have any RTC_CLKIN pin, only the XTAL32/EXTAL32 pins for the crystal.

Using KDS v3.1.0 I do not have any issues to set your required configuration, see below:

Regards!

Jorge Gonzalez

Re: Clocking the MK20FX512 with Processor Expert?

simonhaines — Mon, 25 Jan 2016 22:54:48 GMT

Thanks Jorge, double-checking my setup shows I had indeed selected the wrong chip (off by one error ha ha). Thanks for taking the time to reply.

topic Re: Clocking the MK20FX512 with Processor Expert? in Processor Expert Software

Clocking the MK20FX512 with Processor Expert?

Re: Clocking the MK20FX512 with Processor Expert?

Re: Clocking the MK20FX512 with Processor Expert?