generating external 20/50KHz clock for interrupt

Other Hardware General Electronics
1

Hi all again,
advice sought please.
What would be the best way to generate a reliable external clock signal of
either 20 or 50KHz? Probably be in a semi hostile environment, ie ~60^C.
I'm hoping for a single chip solution, ie system posts and send config info
to clock generator, system pause for a sec for everything else wake etc,
then starts reading the clock.
Oh, accuracy would be really nice, say at least +-1ppm, but much higher
would be better.

Many thanks again,
Andrew

2

Just buy a 50khz crystal resonator with the tolerance you need.

If it needs heating, put it in a box with a big resistor and a temperature controller.

3

1 ppm would be expensive, but here are some high temperature solutions http://www.statek.com/featured_high_temperature_products.php