In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

I answered my own question.  This all may be nit-picking, but The Art of Electronics mentions that DIY oscillators, even with crystals, often end up at the wrong frequency.  The idea here is to achieve .01% at the desired frequency for RS-232 and other asychronous serial interfaces.

The SX-28 at 4Mhz has C1 at 15pf and C2 at 22pf with an Rf of 1Mohm [Fuse setting 010]

                At 8Mhz has C1 at 56pf and C2 at 33pf with an Rf of 1Mohm [Fuse setting 011]

 

The SX-48 or SX-52 

                At 4Mhz has C1 at 33pf and C2 at 56pf with an Rf of 1Mohm [Fuse setting 011]

                At 8Mhz has C1 at 22pf and C2 at 56pf with an Rf of 1Mohm [Fuse setting 011]

I suspect that you will have an oscillator regardless of getting it right or wrong - just not the frequency you want to hold at.  Also, the simple RC circuit of one resistor and one capacitor at .1% accuracy looks mighty useful for merely driving a set of servos.

I am finished asking any questions about this until I actually acquire both a scope with appropriate bandwidth [75-100 Mhz] and a capacitance meter.  It seems that the circuit board alone could provide your capacitace.

The TTL oscillators [in the tin cans with 4 wires that plug into a DIP] are quite nice and by far the most reliable DIY solutions - no scope is needed.  But my 24Mhz draws 30ma of current. That seems about equal to the SX-28 at that frequency.  Not exactly micropower.

Thanks again for the help.

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