DT’s Elapsed Timer Magic Trick

[Art]

Hi Guys

Do you think it's possible for a program running on pic 16F628A with no additional hardware,
connected only to:
1) a power supply
2) a single wire clock signal to pin 16 CLKIN
3) an LED
to tell what frequency the hardware is running at and adjust DT's Elapsed Timer constant
accordingly so the LED will flash once per second no matter what crystal is connected?

I think the answer will be no, but already disagree
If it turns out too easy, I won’t bother posting the video so fire away!
Cheers, Art.

[Art]

This is the hardware....
A hardware selectable logic buffered clock, or you can turn them all off and the pic won’t run at all.

[Demon]

So where's the LIKE button?

Robert

[Art]

Thanks
If it is figured out I want it outed, and if not I’ll take it to the world of YouTube but will then give it up

[pedja089]

It's easy, when PIC have internal osc...
You can use same method to calibrate internal OSC, when OSCCAL value is erased.
Just feed in known clock reference and adjust internal clock Until you get correct result.

[Art]

There’s no known clock reference being fed into it.
It can currently be any of three clocks so it’s unknown.
The pic’s clock is set to HS, and is clocked by one of the three signals connected.
8, 16 or 24 MHz.