Counting losses using 74LS93

Thread Starter

abrar.haque

Joined Feb 23, 2021
12
I am trying to get the circuit to work as a lamp handball game and to count the number of losses for player 2. the circuit works as desired but i cannot get the number of losses to count correctly on the 7 segment display. the current circuit counts the score for player 2 but when the circuit is started from the left hand side, for player 1, the 7 segment display increments when the player presses the pulser when it should not. i have attached what i have done so far.

any help would be greatly appreciated. thank you
 

Attachments

ericgibbs

Joined Jan 29, 2010
12,260
hi abrar,
Welcome to AAC.
I am unable to open the unzipped format, please post the circuit diagram directly inside your post.
E
 

Thread Starter

abrar.haque

Joined Feb 23, 2021
12
i have managed to deduce that the issue is with the ckA input of the 74LS93 IC and the connection it has to D of the left hand side 74LS74
 

dl324

Joined Mar 30, 2015
12,681
i have managed to deduce that the issue is with the ckA input of the 74LS93 IC and the connection it has to D of the left hand side 74LS74
Is this problem in the Proteus simulation or on a breadboarded circuit?

You have floating inputs on the display decoder and don't have the switches used for clocks to the flip flops debounced.
 

ericgibbs

Joined Jan 29, 2010
12,260
hi abar,
I have managed to improve the resolution of that in post #2, should help others to view.

E
AAA 1221 19.14.gif
 
Last edited:

dl324

Joined Mar 30, 2015
12,681
You're allowing the inputs to U6:B, U4:C, U9:A, and others float.
clipimage.jpg
You have duplicated blocks of logic; why didn't you draw them the same way?
 

Thread Starter

abrar.haque

Joined Feb 23, 2021
12
it is within the proteus simulation. i have not build it on a breadboard yet. i do not understand when you say they are floating as they have a connection when the push buttons are pressed to start the circuit as well as for to reverse the direction of the lights. this is a small subsystem i am going to incorporate in to a large system. apologies for any confusions caused by my bad proteus skills.

circuit works as intended without the 7 segment display but i am having issues with displaying the score of each player correctly. have you run the simulation on proteus?
 

dl324

Joined Mar 30, 2015
12,681
i do not understand when you say they are floating as they have a connection when the push buttons are pressed to start the circuit as well as for to reverse the direction of the lights
The gates I mentioned have floating inputs when the corresponding switches are opened. That's not a good design practice.

When I was a technician working on refrigerator sized computers made from TTL, the computer would malfunction if inputs were left floating. That was one of the ways instructors tested our troubleshooting abilities. They'd remove the solder from one of the input pins of an IC and make sure the pin wasn't contacting the plated through hole.
have you run the simulation on proteus?
Proteus isn't a free simulator, so I have to analyze your circuit the old fashioned way.
 

Thread Starter

abrar.haque

Joined Feb 23, 2021
12
counting the number of losses.pngI have tried using the 74161 and a nand gate but still encounter the same issue. the display increments every time a player starts the game, as opposed to when the light disappears. the display shows 0 when i press the reset so that works fine, just the automatic scoring when a player loses and the light disappears is proving to be very troublesome. i have tried using logic and timing but to no avail
 

ericgibbs

Joined Jan 29, 2010
12,260
hi,
OK,
Why have you chosen the 7493 [binary] and not the 7490 [decimal] counter.?

Regarding floating Input pins, as they are TTL they will pull up internally to a High state,BUT it it is not recomended.
Use a 1K pull up to Vsupply.

Post a circuit showing only One player circuit and we can work thru it with you.

E
 

Attachments

ericgibbs

Joined Jan 29, 2010
12,260
hi abrar,
It is always a good idea to sketch out the project before drawing in a simulator.
This image is a rough guide to get you started, do you follow the diagram OK.?
E
cntr1.gif
 

Thread Starter

abrar.haque

Joined Feb 23, 2021
12
Picture1.jpg

i have added another display to count the score of the first player, and addressed the floating inputs.

the circuit works as follows:

first player pressed the bottom left start switch and the first outputs comes on to indicate the are going to serve. then the pulser next to pulser a is pressed so they have taken their shot and the outputs light up one after the other. the direction of the outputs can be changed when the last output comes on if the second player presses their pulser (connect to D of flip flop) in time. If they do not then all outputs are now off and the first player has won that round and therefore the display should increment. this is also the case for when the game is started by the second player. if a player presses their switch too early or too late then all outputs turn off and the player who presses it too early or late then loses that round.

the issue i am having is that when player 1 pressed the pulser to serve, the second display increments. this is also the case for when the second player starts the game. the circuit works correctly when the displays have been removed, but there is an issue the connection form ckA to D on both 7493s, however I have no idea where to make this connection to make the displays increment when a player loses the game.
 

dl324

Joined Mar 30, 2015
12,681
Passing documents in .doc format is a sloppy habit. Lot of people would not touch them (me too).
I recall doing some testing and convined myself that .docx files were safe. At least in Word.

At least the OP turned of that annoying grid. Style is a completely different matter...
 

atferrari

Joined Jan 6, 2004
4,245
I recall doing some testing and convined myself that .docx files were safe. At least in Word.

At least the OP turned of that annoying grid. Style is a completely different matter...
I recall learning how to create some relatively simple macros that at least could result annoying if not dangerous. Forgot after 20 years how to prepare them for Word and Excel. No interest in running across someone who still remembers how.

BTW, in my activity, I can say that in the last 25++ years all I sent for anyone to read was in .pdf
 
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