On Thu, 24 Sep 2015 05:30:35 -0700, Jim Lux wrote:
> > What would be interesting is if there's a pin on the Arduino/Teensy that > you could feed a high quality oscillator to, and then do counting with > that. The K20 microcontroller has a mindbendingly large number of > features and alternate pin functions. As i see it, from the DS. , it seems like there are 2 options. External Oscillator (the system clock clock) , or External Timer clock (limited to system clock/4) Electr. specs https://www.pjrc.com/teensy/K20P64M72SF1.pdf Family Ref https://www.pjrc.com/teensy/K20P64M72SF1RM.pdf Seems like the EXTAL pin (main oscillator) accepts an Oscillator signal (max VDD + 0.3v) (Electr specs pg.10) Ext Osc Connection (Family ref. pg. 526) Also see PLL jitter (Electr specs pg.27 table 14) There is a possibility to clock the FlexTimerModule by an external clock (FTM_CLKIN/EXCLK - Max freq is Mainclock/4) , see (Family Ref. pg. 113, 214 & 774) If using EXTAL and USB , you want to make sure that the USB part still gets it's 48Mhz (via the PLL mul/div). Maybe divide 10Mhz (XTAL) by 2 , and mul by 48, in the PLL. Rgds CFO - Denmark -- E-mail:[email protected] _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
