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Electronics Forum / Basics / April 2006



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BCD Counter

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mirza1867@gmail.com - 27 Apr 2006 01:24 GMT
After getting flamed for not cross posting last time, Ive learned the
error of my ways.

With some great help, I was able to build the complete circuit.

I just had to connect two seven segment displays to it and make it able
to count up to 99.

I did that but I havent uploaded it as it doesnt look neat and would be
a pain to look at.

Now, during play the counter counts up at a regular pace. Then if I
press stop it resets or if I press pause it stops the counter.

The thing I cant seem to get is how to get Fast Forward to work. I need
to make the counter go faster and have been unable to do that.

The counter counts up using a bcd decade counter. As mentioned it
counts fine, but I cant seem to figure out how to make it go faster.

[url=http://img176.imageshack.us/my.php?image=compeng0tm.jpg][img=http://img176.image
shack.us/img176/7059/compeng0tm.th.jpg][/url
]
mirza1867@gmail.com - 27 Apr 2006 01:26 GMT
sorry... I wasnt able to post the image correctly.

You can simply click on on of the urls to view what I have done so far
Ken Taylor - 27 Apr 2006 01:54 GMT
> After getting flamed for not cross posting last time, Ive learned the
> error of my ways.
[quoted text clipped - 17 lines]
>
> [url=http://img176.imageshack.us/my.php?image=compeng0tm.jpg][img=http://img176.image
shack.us/img176/7059/compeng0tm.th.jpg][/url
]

I don't know what circuit you're using for your clock display, but if
you use the fast forward output from the circuit you've linked to you
can use it to gate either 'normal' speed clock pulses to your display
circuit or higher-speed clock pulses (from further up the divider chain).

Ken
mirza1867@gmail.com - 27 Apr 2006 02:08 GMT
> I don't know what circuit you're using for your clock display, but if
> you use the fast forward output from the circuit you've linked to you
> can use it to gate either 'normal' speed clock pulses to your display
> circuit or higher-speed clock pulses (from further up the divider chain).
>
> Ken

Ive uploaded the image of the clock display now.

http://img146.imageshack.us/my.php?image=untitled9sy.jpg

Right now it counts up automatically to 9 and then resets.
Ken Taylor - 27 Apr 2006 03:12 GMT
>>I don't know what circuit you're using for your clock display, but if
>>you use the fast forward output from the circuit you've linked to you
[quoted text clipped - 8 lines]
>
> Right now it counts up automatically to 9 and then resets.

Where are you getting your clock from? Use the fast forward signal to
select a higher clock speed.

Ken
mirza1867@gmail.com - 27 Apr 2006 03:35 GMT
> >>I don't know what circuit you're using for your clock display, but if
> >>you use the fast forward output from the circuit you've linked to you
[quoted text clipped - 13 lines]
>
> Ken

the clock (squiggly line) is just there to represent where the input
would come from.

How do I select a higher clock speed ?
Luhan - 27 Apr 2006 04:12 GMT
> the clock (squiggly line) is just there to represent where the input
> would come from.
>
> How do I select a higher clock speed ?

This is a mental exercise, no one would use this kind of circuit today.
So just insert a binary divider and specify a faster clock.  Then
select the raw clock or the output of the divider.

I once had to repair a TEAC reel to reel tape deck with logic like this
using about a dozen relays.  After attempting to trace the logic
problem for some time, I concluded that the circuit was not defective,
but that the signal simply got lost trying to find its way thru it...
:)

Luhan Monat (luhanxmonat-at-yahoo^dot^com)
http://members.cox.net/berniekm/
"Reality: what a concept!"
JLU_EE - 27 Apr 2006 06:59 GMT
I agree with Luhan.
But it is interesting.
JLU_EE - 27 Apr 2006 06:59 GMT
I agree with Luhan.
But it is interesting.
John Fields - 27 Apr 2006 21:38 GMT
>> >>I don't know what circuit you're using for your clock display, but if
>> >>you use the fast forward output from the circuit you've linked to you
[quoted text clipped - 18 lines]
>
>How do I select a higher clock speed ?

---
I've posted a front end for your counter circuit on
alt.binaries.schematics.electronic under "BCD counter (from seb)."

Signature

John Fields
Professional Circuit Designer

mirza1867@gmail.com - 27 Apr 2006 22:41 GMT
> >> >>I don't know what circuit you're using for your clock display, but if
> >> >>you use the fast forward output from the circuit you've linked to you
[quoted text clipped - 26 lines]
> John Fields
> Professional Circuit Designer

sry for my noobness, but I dont know how to access
alt.binaries.schematics.electronic
John Fields - 27 Apr 2006 22:57 GMT
>> ---
>> I've posted a front end for your counter circuit on
>> alt.binaries.schematics.electronic under "BCD counter (from seb)."
>
>sry for my noobness, but I dont know how to access
>alt.binaries.schematics.electronic

---
Get a USENET provider.

But, I had mercy on you. Look in your inbox.

Signature

John Fields
Professional Circuit Designer

Rich Grise - 28 Apr 2006 17:30 GMT
On Thu, 27 Apr 2006 14:41:42 -0700, mirza1867 wrote:

>> >How do I select a higher clock speed ?
>>
[quoted text clipped - 3 lines]
> sry for my noobness, but I dont know how to access
> alt.binaries.schematics.electronic

It's not noobness - it's from posting at googlegroups. (BTW, it's worth
noting that you _do_ quote context, and you _do_ bottom-post - these are
_good_ things. :-) )

But, as John said, get a real news server - ask your ISP, they probably
already have one, and will be happy to teach you to access it.

Good Luck!
Rich
DaveM - 27 Apr 2006 21:32 GMT
> After getting flamed for not cross posting last time, Ive learned the
> error of my ways.
[quoted text clipped - 17 lines]
>
> [url=http://img176.imageshack.us/my.php?image=compeng0tm.jpg][img=http://img176.image
shack.us/img176/7059/compeng0tm.th.jpg][/url
]

Just a few observations about your circuit.
You don't show any pullup or pulldown resistors on the gate and flipflop inputs.
Are you using any?
What technology are you using for your ICs (TTL/LSTTL/CMOS, etc.)?
I recommend pullup resistors on every input that might float while any of the
switches are not being pushed.  Floating inputs can cause all kinds of grief.

The fast-forward circuit needs a faster clock than the normal speed counter
circuit.  Find a faster clock source for that counter.

Signature

Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the
address)

They call it PMS because Mad Cow Disease was already taken.

 
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