How to count pulses per second ?

[Anthony Fremont]

Anthony, I'm using Google-Groups, where did you post the schematic &
code ?

It's on ABSE and I mailed you the stuff directly. Let me know if you need
any help.

 

[Mike C]

It's on ABSE and I mailed you the stuff directly. Let me know if you need
any help.

Anthony Thanks alot for the pic code ! truly appreciated. pretty
impressed that you wrote this directly in asm... i would really need
to dig out some old college textbooks to refresh my asm memories... I
was really hoping for some C code After I order a pic kit, i'll try
burning the asm code and see what happens... but i'd need to re-write
in C down-the-line anyway, since I'd want to expand on it without
coding it all in asm..

JF: Funny thing now, I ordered the HC4017.. and started putting
pieces together, when I noticed that the "Divide by 10 counter" was
dividing a pulse without anything on the input line ... looks like
this chip is so sensitive that its picking up "AC Hum" on the input
line... all by itself ... any suggestions on how to get rid of it ?

Thanks alot !
MC

 

[ehsjr]

JF: Funny thing now, I ordered the HC4017.. and started putting
pieces together, when I noticed that the "Divide by 10 counter" was
dividing a pulse without anything on the input line ... looks like
this chip is so sensitive that its picking up "AC Hum" on the input
line... all by itself ... any suggestions on how to get rid of it ?

Bypass the supply near the chip (.01 uf to ground
from +Vdd) on general principles. Your input is
the clock line - pin 14. You don't want to leave that
floating. What are you driving it with? Tie the pin
to ground through 10K to see if that makes a difference.

Ed

 

[Anthony Fremont]

Anthony Thanks alot for the pic code ! truly appreciated. pretty
impressed that you wrote this directly in asm... i would really need
to dig out some old college textbooks to refresh my asm memories... I
was really hoping for some C code After I order a pic kit, i'll try
burning the asm code and see what happens... but i'd need to re-write
in C down-the-line anyway, since I'd want to expand on it without
coding it all in asm..

Your welcome. The code is specific to a 12F683, so if you want to run
it on another model it will need some changes. I highly suggest you stick
with assembler, at least until your comfortable with it. C is nice, but
there is nothing like assembler to teach you how it all really works. Good
luck, and if you want a preprogrammed chip, just let me know.
www.piclist.com is a great resource for this stuff.

JF: Funny thing now, I ordered the HC4017.. and started putting
pieces together, when I noticed that the "Divide by 10 counter" was
dividing a pulse without anything on the input line ... looks like
this chip is so sensitive that its picking up "AC Hum" on the input
line... all by itself ... any suggestions on how to get rid of it ?

If the input pin was floating, that's not very surprising. CMOS inputs are
quite sensitive. Floating inputs seem to like to hover around the switching
point, rapidly toggling back and forth. You'll probably be ok once it's
connected, but use bypass caps (.1uF or .01uF) on the power pins of the chip
anyway. If you still have problems picking up the stray AC you can try
placing ferrite beads over the input line.