Posted on May 17, 2011 at 11:36I've been looking into some problems with an ST9 design done by a previous engineering team and have some real issues with the crystal circuit they came up with.
The capacitor on the OSCIN side of the crystal is tied to +VCC rather than ground. And they tied an analog switch circuit to the OSCOUT side of the crystal, and it defaults to the on state during power up. This adds a bit more capacitance to the circuit on start up than the max.
Also, I'm a bit confused by the information on the oscillator in the documentation. They show an internal switched parallel resistor in one diagram, and then an external parallel resistor in another. Should I have an external resistor?
Thanks for any guidance you can give me.
George Richardson
Canberra Dover
[ This message was edited by: gprtech on 27-01-2005 22:03 ]
