Natty said:
Hello everyone!
I am using a presettable BCD up/down counter (CD 4029BE) in my project.
I want to test the counter IC by giving a clock input. I tried using a
square wave as a pulse from the sigal generator. It didnt work, All
other connections in the circuit seems to be correct. I really doubt
the way I am giving the clock pulse to BCD up/down counter. I wud very
much appreciate ur help.
Thanking you.
Raghs.
Hello, Raghs. As is always the case with logic ICs, go to the data
sheet first. They are meant to be used and understood easily, and are
fairly staraightforward once you get the hang of reading them.
http://www.onsemi.com/pub/Collateral/MC14029B-D.PDF
The 4029 is a versatile counter chip, which is presettable,
cascadeable, and can count up or down in either decimal (base 10) or
binary (base 16). What more could you want? Possibly a little simpler
to use? Can't have everything, sir.
Anyway, the first thing you should look at is the signal generator.
Most of them have TTL outputs, and that should work well if you power
the Device Under Test (DUT) IC with a +5V supply. If your signal
generator doesn't have a TTL output, set it for square wave output and
use the DC offset to make the + and - excursions of the output logic
level (+5V and 0V).
Now look at the IC itself. Remember that all inputs have to be tied to
a logic level with CMOS. You need to figure out what to do with the
veritable plethora of control pins. That depends on what you want to
do with the chip.
But let's do it simply, and suggest that you just want to set it up as
a base 10 up counter with no preset (just to see it work). To do that,
you tie pin 1 and pin 5 low (0V). Pin 9 should be low to divide-by-10,
and pin 10 is high to count "up", Now tie all your preset pins (4, 12,
13, and 3) low just to have them at any logic level. Now you can power
up and apply your TTL Output from the signal generator to the CLK (pin
15).
Look at your output pins and see the IC count up in BCD before your
eyes.
By the way, if you seem to have trouble with one manufacturer's
datasheet, look at another. The slightly different explanation may
clear up any residual questions.
Good luck with your class, sir.
Chris