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K60 OSC032CLK / reference timing

Question asked by Tibor Somogyi on Nov 10, 2016
Latest reply on Nov 14, 2016 by Tibor Somogyi


I am working with the TWR-K60F120M board ( MCU=MK60FN1M0VLQ12 ) as "proto board" for my project, and would like to avoid the 32 kHz RTC oscillator for my final design. However, the final design requires a quite precise time-keeping function, so I wonder whether I can make it from other sources. One of the promising signals is OSC032KCLK - an output signal from System Oscillator 0. With such a name I could expect that it is a 32.768 kHz clock with quartz precision - but the Reference Manual does not say too much about this clock. So my question(s) are:

- Is this OSC032KCLK clock is an 32.768 kHz signal independently of the external crystal / oscillator feeding System Oscillator 0 ? ( e.g. what will be the frequency of OSC032KCLK if I feed System Oscillator 0 with the 50 MHz external oscillator on the board ? )

- If the response to the previous question is that OSC032KCLK has the same frequency than the input signal, my understanding is that I could use other time references, such as LPO or MCGIRCLK - this later is even trimmable. Does someone have some experiences of using these time references ? I would like to know whether I can count on their stability ( these are not based on some quartz resonators ), mainly under varying temperatures ( 40 ..120 degC )

Thanks and regards