----- Original Message -----
From: dal wheeler <dwheeler@INSIGHTEK.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, June 28, 2000 2:18 PM
Subject: Re: [PIC]: P 'Two speed' clock support


> How much current would an external clock driver w/ selectable dividers
draw
> as opposed to a "traditional" high-speed crystal w/ pic/sx in sleep mode
> when not in use?  Is there such a thing as a selectable divider regular
> crystal?  Also I've seen it proposed to switch between low speed RC and
high
> speed crystal; how can one do that?  Is'nt that a setting burned at
program
> time?
> I

This can be done by setting the chip to RC mode, but then driving it with an
external oscillator (_not_ a crystal!). Again, the trick would be to arrange
for 'glitchless' transitions.

Bob Ammerman

> ----- Original Message -----
> From: "M. Adam Davis" <adavis@UBASICS.COM>
> > I believe I've seen oscillators with built in selectable dividers, but I
> cannot
> > remember where.  You can use a seperate oscillator and divider, and use
a
> pic