i need help with making a digital clock using 74192 and 7447 and seven segement

Thread Starter

shirotpoison

Joined Mar 23, 2024
32
What does happen? And what happens to the seconds counter?
the secound counter works perfectlely but the munits counter go 1 when the secound counter reach 40 secounds , the probleme is with the AND gate and i want some soulotion to fix tis probleme
 

Ian0

Joined Aug 7, 2020
10,076
the secound counter works perfectlely but the munits counter go 1 when the secound counter reach 40 secounds , the probleme is with the AND gate and i want some soulotion to fix tis probleme
Check the connection between the "2" line and the AND gate.
 

MrChips

Joined Oct 2, 2009
30,987
74192 is a BCD counter. You do not need to reset the units counter.
You do not need the resistor and capacitor at the output of the AND gate. Connect the output directly to CLR on pin-14.
 

dl324

Joined Mar 30, 2015
17,015
its a university project
You have floating inputs on U4, U4, U7, and U8. You don't need the resistors R15/R30 and capacitors C1/C2.

There's a better way to cascade 74192. It might be in the datasheet. It's more helpful for down counting, but can be used for up and down.

EDIT: From TI datasheet description:
1711292338083.png

The units resetting comment isn't relevant because you have reset connected to ground.
 
Last edited:

Thread Starter

shirotpoison

Joined Mar 23, 2024
32
74192 is a BCD counter. You do not need to reset the units counter.
You do not need the resistor and capacitor at the output of the AND gate. Connect the output directly to CLR on pin-14.
when i connect the AND gate directely it stop counting on 40 , so i add the resistor and the capacitor
 

Thread Starter

shirotpoison

Joined Mar 23, 2024
32
You have floating inputs on U4, U4, U7, and U8. You don't need the resistors R15/R30 and capacitors C1/C2.

There's a better way to cascade 74192. It might be in the datasheet. It's more helpful for down counting, but can be used for up and down.

EDIT: From TI datasheet description:
View attachment 318281

The units resetting comment isn't relevant because you have reset connected to ground.
can you please explain more or provide some schematic ,or tell me how to connect the pins correctly because when i remove the capacitor and the resistor the seconds counter stop at 40 seconds
 

dl324

Joined Mar 30, 2015
17,015
tell me how to connect the pins correctly because when i remove the capacitor and the resistor the seconds counter stop at 40 seconds
The simulator may be giving bad results when you have floating inputs. Fix that and try again. There is no need for any resistors or capacitors to cascade those counters.

I can't show you how I'd do it because this is schoolwork.
 

Thread Starter

shirotpoison

Joined Mar 23, 2024
32
i dont have much
The simulator may be giving bad results when you have floating inputs. Fix that and try again. There is no need for any resistors or capacitors to cascade those counters.

I can't show you how I'd do it because this is schoolwork.
i dont have much time so if you help me with this part would save a lot of time ,because i already tried all i know
 

Thread Starter

shirotpoison

Joined Mar 23, 2024
32
If it stops counting on 40 instead of 60 then something is wrong with your connections to the AND gate.
Check your wiring.
the wiring is connected to the state of ''0110'' witch mean 6 , but stops at 40 but the resistor the capacitor fixed the problem
 

MrChips

Joined Oct 2, 2009
30,987
the wiring is connected to the state of ''0110'' witch mean 6 , but stops at 40 but the resistor the capacitor fixed the problem
You need to examine what is the problem. You need to explain how it is able to fix the problem.
How can state 0110 appear before 0100? There are no "race" problems with 74192 that I am aware of in this situation.
 

dl324

Joined Mar 30, 2015
17,015
i dont have much time so if you help me with this part would save a lot of time ,because i already tried all i know
Time isn't relevant for Homework Help; we still won't do your work.

Other than the floating inputs, unnecessary resistors and capacitors, the logic looks correct. Fix the floating inputs and remove the resistors/capacitors. If it still doesn't work, I'd suspect Proteus or some connection that isn't being interpreted correctly.

I have simulated 12 and 24 hour clocks using 74LS192 (which is logically the same as 74192) and the logic from the 10 second counter is the same as what you have (minus the extraneous components). I cascaded the counters differently, but your method should work (after you fix the floating inputs).
 
Top