> >btw - is a resistor the answer for the spike?  this seems to eliminate
> >the spike altogether, but it rounds things off a little...does this
> >eventually
> >cause problems ?
>
> What spike? If you're scoping the output pin and seeing this sort of
thing,
> it's probably that your scope probe is mismatched or the compensation
isn't
> trimmed correctly.
>
>       .
>      |  .
>      |    -----------.
>      |                |
> ----.                |    ------
>                       |  .
>                        .
>
> Best regards,
>
> Spehro Pefhany --"it's the network..."            "The Journey is the
reward"
>

OK. this must be oscilloscope operator error.  this thing has a BW limit
setting,
and at 100 MHz, all pulses, square waves, whatever, have a peak volatage
level
of between 9.0 and 9.5, but the display is clearly showing around 5 vdc,
visually.
(on the BW 100MHz setting)

but, when you select the BW limit of 20 MHz, the display is a more perfectly
'squared off' wave.

btw-- this is the 18F452, with the HS-PLL, 40mhz setup
and btw, I cannot see how to get a faster than 4 instructions cycles,
for a on/off toggle, or 2.5 MHz pulse, not symetrical.....
thanks

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads