Interrupt RPM and Taylors Elapsed time on 18F4620

[Bruce]

BEER thief

That is just so WRONG ... hit squad has been mobilized....

[Darrel Taylor]

If Charles hadn't done it with DT_INTS, I might have been upset (longer).

But he did ...
More things to simulate.

I might have to send Charles a 6-pack too.
<br>

[Bruce]

You ain't getting off that easy bud .. you still have to prove me wrong, and show a solution to the problem....)

[Darrel Taylor]

Agreed, and accepted.

But just so I'm clear, what I'm proving wrong is that it's a revision or errata sheet problem with the 18F4620 itself.
And that using an 18F4431 will solve it?

In other words, I gotta do it in hardware too?
<br>

[Bruce]

You just have to prove that my recommendations throughout this thread (for this specific controller) were wrong, and show your solution to the problem - using the same controller.

My point thus far has been that this particular controller is doo-doo. Your entry point on this thread stated;

I think you need to clear the timer sooner.

[Darrel Taylor]

You just have to prove that my recommendations throughout this thread (for this specific controller) were wrong, and show your solution to the problem - using the same controller.

I had missed post#22 while working with proteus, but it didn't matter ... it works too.

So, at the risk of loosing beer ... and buying chips ...
Other than the problems that were fixed earlier ... CCP1CON missing ... period instead if CCPR1L:H ...

This is the problem ....

The 4620's oscillator is running at 20.13 mhz

If it's a crystal, the caps are wrong or the crystal is off (or a radio crystal).
If it's a cheap resonator, then it's only to be expected.

That's my story ... and I'm sticking to it.
No way to prove it unless Toby checks it.

If I run the simulator at 20.13mhz, I get the exact same numbers across the board.
<br>

[Charles Linquis]

I rive in China. The address in my bio is just to confuse people.

[Tobias]

Theoretically I should be able to swap oscillators and the problem will be on the 877A. Give me a bit and I will try that.

Here is a link to the one I have on the boards.
http://mouser.com/ProductDetail/Kyoc...XFVfiWpjmqo%3d

[Bruce]

I think Darrel nailed it with the oscillator problem. Nice catch. I just assumed you were
testing different PICs on the same board.

[Tobias]

its the osc. I had no idea there could be that much variance. Can you suggest a better part number?

[Darrel Taylor]

Woohoo!
I can taste it already.

[Darrel Taylor]

Can you suggest a better part number?

The datasheet for that resonator shows that they have other versions of the same thing but with tighter tolerances (down to 0.1%).
At least it will have the same footprint.

With 0.1%, at 6000 RPM it will read between 5990-6010. (according to proteus).