Is it possible to 24 MHz oscillator instead of crystal on i.MX28?

[jschoen]

Is it possible to connect a 24 Mhz oscillator to XTALO of i.MX28 instead of using 24 MHz crystal?  I don't see any documentation on bypassing the internal oscillator.

Thanks.

[Yuri · Accepted solution]

   Generally, it seems to be possible to apply an external 24MHz clock signal

to XTALI and leave XTALO open, however, the amplitude of an external clock

signal must not exceed VDDXTAL, that is typically around 1.0V.

   Next, an external oscillator may be connected to XTALO pin instead of XTALI pin. In addition,
an AC coupling capacitor should be place close to the i.MX28 so that the internal bias of the
i.MX28 circuit will not be affected.
   However, this configuration is not recommended in practice. The XTALO  as input is a high-impedance

one and therefore it increases noisy environment of the whole i.MX28, including the DCDC converters.