feed RTC_XTALI with square wave

[chris321]

Hello Community,

I did not found anything about this in the datasheet.

Is it possible to feed the (analog) pin RTC_XTALI from the i.MX28 with a square wave?

For example the square wave output from an external RTC.

Best Regards

[4guin4g4 · Accepted solution]

Yes, a squared wave can feed the RTC_XTALI. yous be sure that it meets the specs in the RM:

"Since the internal RTC circuitry is powered from VDDXTAL which

voltage level is around 1.0V, the input 32K clock signal level on  RTC_XTALI should be 1V also. "

[chris321]

Thank you Carlos,

I do not want to embarrass myself, but in wich Reference Manual did you found this sentence?

The downloadable version is Rev. 1, 2010, in this version I did not found it.

If I feed the XTALI with a 1V squared wave, what about the XTALO? Put it to GND, or let it floated?