Kinetis MicrocontrollersのトピックRe: K60 Clock Requirements https://community.nxp.com/t5/Kinetis-Microcontrollers/K60-Clock-Requirements/m-p/177701#M1579 <HTML><HEAD></HEAD><BODY><P>No. You do not need the 32k clock unless you specifically use it for some device module.</P><P>&nbsp;</P><P>I've been using a custom dev board with only a 50 MHz high speed EXTAL for about 18 months no problem (well, no oscillator problems).</P><P>&nbsp;</P><P>You can leave XTAL32 float, we've grounded EXTAL32 thru a 10M resistor, but I think that is just overkill for possible noise reduction, I do not believe it is required to actually do that. In fact it might be better without. I think the designer just did it so Altium would not complain it was a floating "input".</P><P>&nbsp;</P></BODY></HTML> Fri, 06 Jul 2012 02:46:34 GMT comsosysarch 2012-07-06T02:46:34Z K60 Clock Requirements https://community.nxp.com/t5/Kinetis-Microcontrollers/K60-Clock-Requirements/m-p/177700#M1578 <HTML><HEAD></HEAD><BODY><P>I am configuring my board to use an external 25MHz crystal for the main clock. Is it absolutlely necessary to also have a 32kHz crystal on your board even if you are not using an RTC?</P></BODY></HTML> Thu, 05 Jul 2012 23:19:56 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K60-Clock-Requirements/m-p/177700#M1578 Carl_7 2012-07-05T23:19:56Z Re: K60 Clock Requirements https://community.nxp.com/t5/Kinetis-Microcontrollers/K60-Clock-Requirements/m-p/177701#M1579 <HTML><HEAD></HEAD><BODY><P>No. You do not need the 32k clock unless you specifically use it for some device module.</P><P>&nbsp;</P><P>I've been using a custom dev board with only a 50 MHz high speed EXTAL for about 18 months no problem (well, no oscillator problems).</P><P>&nbsp;</P><P>You can leave XTAL32 float, we've grounded EXTAL32 thru a 10M resistor, but I think that is just overkill for possible noise reduction, I do not believe it is required to actually do that. In fact it might be better without. I think the designer just did it so Altium would not complain it was a floating "input".</P><P>&nbsp;</P></BODY></HTML> Fri, 06 Jul 2012 02:46:34 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/K60-Clock-Requirements/m-p/177701#M1579 comsosysarch 2012-07-06T02:46:34Z