Hi everyone,

I’m designing a two-digit chess clock (max 99 seconds per player) in Multisim using non-programmable components (no microcontrollers). I’ve outlined the basic structure but need help refining the design and troubleshooting. Here’s what I have so far:

Current Design:

• Counters: 74LS192 (BCD, up/down) for each player (units + tens).
• Displays: Common-cathode 7-segment LEDs with 74LS47 decoders.
• Clock: 555 timers (1Hz) for each player, gated via flip-flops (74LS74) for turn control.
• Controls: Push buttons for start/pause, player switch, and reset.

 

Welcome to AAC!

Is this homework?

It would be easier to read your schematic if you avoided wires over text, unnecessary wire jogs, and scenic routes. Using pin order symbols is generally not helpful and the symbol for the AND gates is useless. You can also print to B&W PDF instead of posting screen shots with that unnecessary grid.

Multisim offers weird routing. You can influence it by holding the shift key down. You can always move wires after placement to make them tidier.

 

It's a project but I'm not very good at multisim.

 

It's a project

Is this a school project?

 

You might consider using a CD40110 up/down counter which directly drives a 7-segment display to minimize the number of parts.

Note that if you drive this CMOS circuit from a standard 74LSxxx TTL circuit output, you will need a 10kΩ pull-up resistor to V+ at each CMOS input.
Alternately you could use all CD4000 CMOS parts, which take little power, and can operate from a supply voltage of 3V to 15V.