DIGITAL COUNTER 00-99

Thread Starter

jony121212

Joined Dec 4, 2023
13
Hello, I have this problem when i simulate the circuit on proteus the counter will stay at 00. I am using ne555 as pulse, 74ls192 as up/down counter. I don't know what is the problem/error on my circuit. Anyone who can help me with this? Thank you for the response.

here is my schematic diagramScreenshot 2023-12-12 235630.png
 

WBahn

Joined Mar 31, 2012
32,823
What have you done to try to track the problem down?

Have you looked at your clock signal to see if it is actually what you expect? If not, then that's where to focus your search efforts.

As @ericgibbs pointed out, you've got some major issues that would prevent any real-world implementation from working. I have no idea how Proteus is going to deal with them.
 

dl324

Joined Mar 30, 2015
18,326
I don't know what is the problem/error on my circuit. Anyone who can help me with this?
The 74LS192 datasheet says that the BI/RBO pin can be left open, but I have no idea how Proteus treats floating inputs. Try connecting it to VCC.

Your drawing style makes your schematic tedious to read. Avoid unnecessary wire jogs and crossings. The pin order on the timer symbol isn't conducive to representing standard timer configurations (inputs should be on the left side, though reset on the top makes sense in this case). The capacitor is backwards. Obviously, Proteus doesn't care...

Your lack of current limiting resistors is disconcerting.
 

dl324

Joined Mar 30, 2015
18,326
here is my schematic diagram
When I'm simulating counters, I sometimes don't follow the preferred left to right flow in situations where I find right to left easier to read:
1702399980568.png
It also helps if you have symbols that facilitate the desired flow. In DigitalWorks, you have to make macros for all commercial parts. The ones it includes are brain-dead pin order symbols.

The simulator I use is digital-only. It doesn't have resistors and the concept of logic families is foreign. So I can mix TTL and CMOS without regard to voltage levels or drive capabilities.
 
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Thread Starter

jony121212

Joined Dec 4, 2023
13
The 74LS192 datasheet says that the BI/RBO pin can be left open, but I have no idea how Proteus treats floating inputs. Try connecting it to VCC.

Your drawing style makes your schematic tedious to read. Avoid unnecessary wire jogs and crossings. The pin order on the timer symbol isn't conducive to representing standard timer configurations (inputs should be on the left side, though reset on the top makes sense in this case). The capacitor is backwards. Obviously, Proteus doesn't care...

Your lack of current limiting resistors is disconcerting.
Sorry, I did it for multiple times, changes the wiring. So my schematic is messy.
 

Thread Starter

jony121212

Joined Dec 4, 2023
13
What have you done to try to track the problem down?

Have you looked at your clock signal to see if it is actually what you expect? If not, then that's where to focus your search efforts.

As @ericgibbs pointed out, you've got some major issues that would prevent any real-world implementation from working. I have no idea how Proteus is going to deal with them.
Yes, I searched for it since last week. Still don’t know what’s the problem.
 

WBahn

Joined Mar 31, 2012
32,823
Yes, I searched for it since last week. Still don’t know what’s the problem.
That tells me nothing useful. HOW did you search for it? What signals did you check? Which ones worked? Which ones didn't?

Post a screenshot of your clock signal at the point where it goes into the digital chips.

If that signal isn't good, not much else has a chance.
 
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