µTasker Forum

µTasker Forum => NXP^TM M522XX, KINETIS and i.MX RT => Topic started by: Javier on April 12, 2018, 02:11:25 PM

Title: Generate 14.3181 MHz clock with the K28
Post by: Javier on April 12, 2018, 02:11:25 PM

Hello

K28
It's possible to generate a 14.3181 MHz clock with uTasker MCG (http://www.utasker.com/kinetis/MCG.html) ?, in order to sync with the colorburst subcarrier from composite video.

Or I need to add an external crystal for this?.

Regards

Edited: I don't use Ethernet

Title: Re: Generate 14.3181 MHz clock with the K28
Post by: mark on April 12, 2018, 05:55:43 PM

Javier

Without using an external crystal the frequencies that can be generated are limited by the FLL multiplication factors. Also the frequency is not very stable (+/-2 % over voltage and temperature range).
Therefore if you need to generate a specific and stable frequency a suitable crystal is the best solution.
This frequency can be used as input to the PLL to generate also your higher frequency system clocks. The oscillators frequency OSCERCLK is then available to output somewhere (you will need to check what outputs are possible with this chip) or else can be reconstructed again (dividing down from the system clock) at a timer output (FlexTimer or TPM, depending on which is available in your device).

Regards

Mark

Title: Re: Generate 14.3181 MHz clock with the K28
Post by: Javier on April 13, 2018, 12:42:05 AM

Thanks you very much,

Regards