I have a assignment which i need to design a 60 seconds stop watch with start/stop and reset functions.

ICs required : 74LS93,74LS00,74LS32
And any other standard logic gates or flipflops.

i have successfully design a MOD60 counter by using a MOD10 and a MOD6. it does count from 00-59 and go back to 00 again.

my next step is to include the start/stop and reset function which i have no idea what to do. My objective is to use 2 pulse switch for the start/stop and reset buttons and to use a preset clear J-K flipflop in my circuit.

-----> http://www.mediafire.com/?88bpjz89fk9fn11 <----- for my multisim file

PS: i know this assignment have been posted many times but i still do not have an idea on what to do with my circuit. therefore i hope anyone of you can give me some suggestion or hints on what to do.

 

A simple way would be to use one button that toggles a flip flop to start/stop the counting.

Use a Buffer with Enable to block or allow the clock to be passed to your counter section via the flip flop output controlling the enable line.