Cext       Rext           AverageFosc @ 5V, 25¡C (PDIP)
20 pF     3.3k           4.68 MHz ± 27%
20 pF     5.1k            3.94 MHz ± 25%


According to page 77 of microchip's 30445B.PDF.
It also covers min. max. RC values, temp. variation, and more.
Only 691 K from www.microchip.com

For stability:
20pF is a good minimum capacitance,
3k minimum R, and 100k is maximum.

</David_V>

----- Original Message -----
From: Graham North <graham.north@LANDINST.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, November 16, 1999 3:16 AM
Subject: RC 4MHz clock


> I am wanting to use an RC oscillator on a 16F84 circuit.
>
> Can anyone tell me what values to use (R and C) for an approx 4 MHz clock.
>