topic Re: mkm34 PLL or FLL in Kinetis Microcontrollers

mkm34 PLL or FLL

Edrianocarlos — Thu, 12 Nov 2015 13:58:49 GMT

Currently i am developing an Flowmeter with mkm34 75MHz.

And i am trying to understand what would be the best option as clock.

In your opinion wich one is more stable PLL or FLL in this microcontroller?

As i could see the PLL needs to have an reference about 32khz is that right? i will not be able to multiply the high frequency xtal oscillator in this case?

Last Does anyone have examples on hou to achieve FEE and PEE using external xtal? i do not intend to use KSDK and i like to understand what is happening

Re: mkm34 PLL or FLL

xiangjun_rong — Fri, 20 Nov 2015 08:05:53 GMT

Hi, Edriano,

I see that you want to get a stable tick for the quadTimer, the quadtimer can get a external clock from crossbar as it's primary clock source. Pls refer to the following part I copy from MKM34RM. In other words, you can connect a clock source from XBAR_IN0~XBAR_IN8 external pins and route the clock source to primary clock via crossbar. From example, you can connect the clock source to pin PTD0/PXBAR_IN2...., while you can set the crossbar as:

XBAR_SEL4|=0x02<<8; it is okay.

I never have test on my board, but I never have a test for the solution, pls have a try.

Xiangjun Rong

Re: mkm34 PLL or FLL

xiangjun_rong — Fri, 20 Nov 2015 08:21:03 GMT

Hi,

I forget to tell you that you have to set the SIM_MISC_CTL to select the IP_BUS, or clock from crossbar as the primary clock for quadTimer..

Xiangjun Rong