On Jul 10, 2005, at 7:04 AM, Ashhar Farhan wrote:
while PLL chips are difficult to find, the 16F84 or the 16F628 are
plentiful. why can't we program the PIC to behave as a PLL on it's own?
the PIC timer can be used to accurately measure the oscillator frequency
(as normal PIC based frequency counters do) instead of displaying the
frequency on a display, it can (in addition) also pump a capacitor that
in turn is used to bias a varactor across the VFO.
if chris and his merry band can do a single chip HnP, there is no need to
assume that they can't turn out a single mirochip PLL too.
Given how cheap a PIC is, I think it's just a matter of time before we stop using standard TTL/CMOS logic, and start programming PICs as replacements. They won't be pin-for-pin replacements, but they'll be easier to locate than some of the more esoteric logic chips.
A PIC PLL sounds like a fabulous project.
Jim N6OTQ
