Frequency Counter/Tachometer

Nrets said:

There has been discussion about Tachometers on this website before, but I just came across this frequency counter and was wondering if it could be used as a Tachometer?

Frequency counter with PIC and 4- to 5-digit LED display

I've built the project on my breadboard, and programmed the PIC, but I don't have a frequency input at the moment. I wanted to use an IR 'detector' and just hook up the output to RA4. Would this work with this design?

Click to expand...

ericgibbs said:

hi,
The FC should work OK, with a low freq input from a IR detector, is it 38KHz.?

Are you using a 16F628 or a 16F628A.?

Click to expand...

Nrets said:

16F628A, nothing happens when I connect power using his HEX file. I've looked at the ASM file, but I am having problems building it and I'm not sure exactly why. Perhaps I'm using the wrong compiler. Anyways, I used the HEX file for 4MHz version, common cathode.

My breadboard is such a mess though that the problem could very likely be hardware related.

It could also be that the code does nothing with the displays unless there's a certain frequency input, some threshold. I'll look at it a bit more.

Click to expand...

ericgibbs said:

hi,
This difference between the 628 and 628A came up in another Fcntr thread.

I'll have a look around.

EDIT:
Look here:

https://www.electro-tech-online.com/threads/help-reading-a-schematic-please.40326/?highlight=16F628A

EDIT2: this is a better link.
https://www.electro-tech-online.com/threads/help-needed-desperately-with-pic-lcf-meter.38935/

Click to expand...

Nrets said:

Code:

#if (COMMON_ANODE)
 #define SSEG_XORMASK 0xFF  ; since 2005-03-21 ... never tested by the author !
#else
 #define SSEG_XORMASK 0x00  ; for COMMON CATHODE: No bitwise EXOR to the pattern
#endif

Code like this... is it just for the compiler? I don't recognize it at all.

I mean, I know what it does, but it's not part of the firmware, correct?

Click to expand...