As the subject says, where can I find information about generating the external clock needed by some mcu's to enter monitor mode (or get their clock signal) when there's no possibility to use a crystal connected to OSC1 and OSC2? I've been looking at freescale's website but I haven't found anything specific yet. Does the clock source need to have an specific shape, rise time, voltage,...?
Can I use a DDS signal generator configured as a pulse generator an 50% duty cycle? Does someone knows the input impedance at OSC1 pin (I couldn't find it among datasheets)?