How long time is needed to oscillate i.MX6 external crystals?

[satoshishimoda]

Hi, communty,

I have a question about i.MX6DQ external crystals.

Do you know how long times is needed to stabilize the oscillation of external crystals (32.768kHz & 24MHz) from the timing VDD_SNVS_IN is supplied?

Actually, a customer will add delay to POR_B and release POR_B after external crystals oscillation is stable, because reraly i.MX6 cannot boot if POR_B is released before external crystal oscillation.

To understand how much delay should they add, the data is needed.

Best Regards,

Satoshi Shimoda

[Yuri]

Oscillator stabilization time depends on environment, schematic, manufacturer and 

may require hundreds msec.

Have a great day,
Yuri

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[satoshishimoda]

OK, I understand depends on many parameter.

BTW, do you have a data of typical oscillation start time of MCIMX6Q-SDP?

And can I calculate the oscillation time with some parameter?

(e.g. benchmark: MCIMX6Q-SDP = 300 msec, oscillation time increase about 10 msec every increase bias resistor 10 ohm)

Best Regards,

Satoshi Shimoda

[Yuri · Accepted solution]

  Hope the app note, linked below helps (assuming typical oscillator considerations

do not depend on processor).

"Practical Considerations for Working With Low-Frequency Oscillators "

http://cache.freescale.com/files/32bit/doc/app_note/AN2606.pdf