counter for counting magnetic microswich press

[turkuaz]

Hi Everyone.
I want to count microswich open-close positon to count disk rotation.
ı have a micro magnetic swich which is produce 2 signal when maghnetic disc rotating 1 time.magnetic swich debounce time is 20 uSec.
I use Pic16F877
This is my code:

..PORTA.4 input pin...
........
..........
loopHy:
IF PORTA.4 = 0 THEN loopHy
count = count+1
Lcdout $fe, $C0, #count:Pause 250(debounce time for slow rotation)
goto loopHy
........

is it Ok .or anybody give me advise.
Thanks.

I solve this problem myself as follows:
.............
loopHy:
IF PORTA.4 = 0 THEN loopHy
count = count+1
While portA.4=1 Then
Lcdout $fe, $C0, #count
Wend
goto loopHy
.............................
It is working nice
thanks everyone.

[mister_e]

Carefull when you use reserved word... COUNT is also a PBP statement. You should change it to something else

Now JUST FOR FUN, and as your current hardware is setuped to use it, try this one which use TMR0

        ADCON1 = 7
        pCount    VAR BYTE
        OldpCount VAR BYTE
        CLEAR
        TMR0 = 0
        OLDPCOUNT = 1
Start:
        pCount = TMR0
        IF pCount != OldpCount then
            LCDOUT $FE,$C0, #pCount
            OldpCount = pCount
            ENDIF
        GOTO Start

[turkuaz]

Carefull when you use reserved word... COUNT is also a PBP statement. You should change it to something else

Now JUST FOR FUN, and as your current hardware is setuped to use it, try this one which use TMR0

        ADCON1 = 7
        pCount    VAR BYTE
        OldpCount VAR BYTE
        CLEAR
        TMR0 = 0
        OLDPCOUNT = 1
Start:
        pCount = TMR0
        IF pCount != OldpCount then
            LCDOUT $FE,$C0, #pCount
            OldpCount = pCount
            ENDIF
        GOTO Start

Thanks for your advice.
I chanced count to sayim(in Turkish)
I do not want to use timer because when disk begin to rotation ( which is slow rotation)micro magnet take to time to pass under the magnetic swich so swich is on position and count is going to count I do not this. I want only one time not elong with passing is going on.

[Acetronics2]

Hi Turkuaz,

Could you tell us what's your MAX RPM ( or half freq ...) counting rate expected ???

Will help for a solution.

I think we could detect only the Low-to-High ( or High-to-Low ) transitions, to get rid of the rotation speed span.

But the debouncing time must fit the max RPM !!!

Alain