Frequency counter-- old project revisit

[Archangel]

Your code looks to be Proton, this forum is M E Labs P basic Pro.

[Vivena]

Archangel
Yes.. But let's put that aside for a moment

If I look at this thread here: http://www.picbasic.co.uk/forum/showthread.php?t=1137

There are three port pins that I'm using in this circuit: http://paulfjujo.free.fr/FREQ/images/weedfreq.jpg, would it then mean I would have to declare 3 pins for use of which portA4 is the input?

Best
Vivena

[mark_s]

Hi, I have tried both of your examples or links.

The first one you only need to input the frequency on the T1CLK pin. Basically you clear timer 1, start tmr1
then pause for 10ms, 100ms or 1s then stop timer1. Read the contents of TMR1L and TMR1H which is your frequency. This method is not very accurate using a pause statement for your time base.

The second, this circuit was designed and sold as a kit by Terry Weeder many years ago. It used the RTCC with a elaborate scheme to gate the input pin on and off then pulsed the rtcc 256 time to purge the result or remainder. This was a very stable and accurate. This used three pins, freq in, gate and purge


http://www.piclist.com/techref/piclist/weedfreq.htm

So to answer your question the code in your first post will not work with the Weeder schematic. There is no timer1 in a pic1684. I started porting the assembly code to PBP at one time, but never finished. Look for the hex file for the pic16f84 and just program a new chip.

[Vivena]

Hello MarK_S
Thank you for the simple explanation. I see the goof-up, I forgot to see the pins involved and assumed that the 16F628 would be good as the other, no wonder I went round in circles.
Thanks for setting me in the correct direction, I will try and read the 16F84A details and see what I can achieve..

I was trying to use Ero's code for a 16F628 unwittingly for a circuit that had a 16F84... whoops..

Thanks once again..

Vivena

[Archangel]

The real issue in using a 628/628A in place of 16F84 is that the 628 has comparator inputs which have to be disabled, otherwise very similar chips, if you have a hex file then go buy a 16f84 and call it good.