Raghunathan R wrote:

"the software-circus with interrupts is best avoided"

No No !!!
Absolutely No !

Interrupts are a very powerful tool and as earlier you learn to use it, as more you like it.

On your task you must never fear any propblems.
The PCA capture works full in hardware so it was fully independend from the main program and the interrupts.

I built also very accurate frequency meter with the AT89C2051 only, which support no PCA. Thus I used the external interrupt and count in software.

And the trick was:

To avoid any delay by the multiplexing interrupt I use simple the higher priority for the external interrupt.

Thus the external interrupt was executed immediately also in this case, that the multiplex interrupt was currently in progress.

On your 8951 derivate there are up to 4 interrupt priorities available. Thus there is absolute no reason, why you should not use it.


Without interrupts especially on bigger projects, the CPU performance drops dramatically.


Peter