2 minute countdown timer using 74190N

[Mark Leghrand]

All to do with the clock... Asynchronous has cascading clocks, whilst synchronous are clocked all at the same time.

what is the difference sir of using the RCO instead of the MAX/Min counter?

 

[Ian Rogers]

Min/Max counter?? Are you talking about fixed counters ie.. decimal counters?

The RCO is a ripple counter ( obviously ) with a carry out function... The decimal counter resets under certain conditions...

 

[Mark Leghrand]

Min/Max counter?? Are you talking about fixed counters ie.. decimal counters?

The RCO is a ripple counter ( obviously ) with a carry out function... The decimal counter resets under certain conditions...

Sir I am pertaining about the two cascading functions here. the 74190N has the RCO and the Max/Min for clocking.

 

[Ian Rogers]

The 74190 is a decade counter.... The Max/Min output serves a a flag to signal that the minimum or maximum count has been reached...

This is from the datasheet.

The maximum/ minimum output can be used to accomplish look-ahead for high speed operation

 

[ericgibbs]

hi Mark,
Is there any reason the 2 Minute down counter would not be acceptable by using a 120 Second down counter, which is very simple to build.?

Is this a school assignment.?

E

 

[Mark Leghrand]

hi Mark,
Is there any reason the 2 Minute down counter would not be acceptable by using a 120 Second down counter, which is very simple to build.?

Is this a school assignment.?

E

Sir Eric yes this is our school assignment.... hmm actually yes! I could consider making it a 120 second timer. However, I wish to make it a chess timer actually.

two 120 seconds are displayed.

120 120

there is a button for each side. When the button is pressed lets say the right button, the left timer will countdown. Vice versa for the other one. Do you think that is simple?

 

[Mark Leghrand]

The 74190 is a decade counter.... The Max/Min output serves a a flag to signal that the minimum or maximum count has been reached...

This is from the datasheet.

alright So how Can I set the IC max/in terminal to recognized that either the max or minimum value was reached?

 

[ericgibbs]

alright So how Can I set the IC max/in terminal to recognized that either the max or minimum value was reached?

hi Mark,
I showed the change from RCO to Min/Max on that rough drawing I posted.

there is a button for each side. When the button is pressed lets say the right button, the left timer will countdown. Vice versa for the other one. Do you think that is simple?

Do you mean the same IC counter drives two LED displays, as selected by a push button.?
It would be easier and cheaper to build two complete counters in the same box, trying to switch the LED pins would be a task!
E

 

[Mark Leghrand]

Sir Eric! I already figured it out with the aid of my colleague Its now capable of counting from 2:00 - 0:00.
here the schem