topic Re: FB Clock Output not rectangular in K32 L Series Microcontrollers

FB Clock Output not rectangular

Kolibri — Wed, 01 Jun 2022 18:17:58 GMT

Hello i´m working with the Development Board FRDMK32L3A6 and i want to use the FB_CLKOUT Pin to clock another Board. Here in this pictures are the settings i use.

Clock_Diagram_FRDMK32L3A6.png

Clock_Pin_FRDMK32L3A6.png

Now i´ve measured the Clock Signal with an Oscilloscope and this is what i get. Am i doing something wrong on my measurement or does the clock signal look like this? How can i change it to be rectangular?

CLOCK.png

Thanks and best regards

Re: FB Clock Output not rectangular

Kolibri — Thu, 02 Jun 2022 15:34:10 GMT

I think i got it, i have to add a series resistor to the signal i will try it tomorrow.

Re: FB Clock Output not rectangular

Kolibri — Fri, 03 Jun 2022 09:45:07 GMT

I´ve tried now with different resistors, the signal changes but it´s not gettin rectangular. Can someone please help me to solve this problem. Is there a formula to calculate the series resistor or is it even needed?

Thanks and best regards

Re: FB Clock Output not rectangular

Kolibri — Mon, 13 Jun 2022 06:11:14 GMT

The clock signal never looks like a perfect squarewave and it works fine like it is.

Best regards Kolibri