[Logisim] How do I store a number for when the program runs?

Thread Starter

bomb1096

Joined Apr 4, 2021
3
Basically, I am building a digital clock and I have all the logic and circuits down but I do not know how to get the year 2020 to display at the beginning of the program. Is there a way to store this information in logic so it can be used at run-time? Thanks
 

MrChips

Joined Oct 2, 2009
24,192
You have not provided us with enough information for us to be able to provide any sensible feedback.
What logic and circuits? Show us a circuit diagram.
What program? What processor/computer/language/platform are you using?
Why do you want to show the year 2020? That is long gone and most people would rather forget it.
 

Thread Starter

bomb1096

Joined Apr 4, 2021
3
1617583859115.png
You have not provided us with enough information for us to be able to provide any sensible feedback.
What logic and circuits? Show us a circuit diagram.
What program? What processor/computer/language/platform are you using?
Why do you want to show the year 2020? That is long gone and most people would rather forget it.
Hello, sorry.

Basically, I have a 0-9 counter that I use to count the years based on input. This is then sent through a 7-Segment controller to control a 7 segment display to display numbers based on the input. This initializes at zero however so when I have 4 of these for the year, it reads out as "0000". This is due to me not knowing how to initialize the circuit with memory. I would like to somehow have the readout be 2021 at the beginning.

Thank you, if you still need more information I would be happy to provide it.
 

MrChips

Joined Oct 2, 2009
24,192
If you are going to display four digits you will need four counters and four displays. You need to draw the full circuit showing four digits. A box with lines on the left and right side is not sufficient. You need to show IC part number, pin numbers, pin functions.

Here is an example of a digital logic diagram.
Reference: https://learn.sparkfun.com/tutorials/analog-vs-digital/analog-and-digital-circuits

1617584608738.png

Many counter ICs have a LOAD function which allows you to preset the counter to any starting value.
 

Thread Starter

bomb1096

Joined Apr 4, 2021
3
If you are going to display four digits you will need four counters and four displays. You need to draw the full circuit showing four digits. A box with lines on the left and right side is not sufficient. You need to show IC part number, pin numbers, pin functions.

Here is an example of a digital logic diagram.
Reference: https://learn.sparkfun.com/tutorials/analog-vs-digital/analog-and-digital-circuits

View attachment 234506

Many counter ICs have a LOAD function which allows you to preset the counter to any starting value.
Thank you for the help but this is a bit out of my domain. I am pretty new to this and this is an intro circuitry course so I am unsure how to read all of this. I checked logisim documentation and there doesn't seem to be a load function. Is there any other type of memory that can load information in a similar fashion?
 

MrChips

Joined Oct 2, 2009
24,192
Counters are made from individual flip-flops which is also a 1-bit counter.

1617588271644.png

Start by learning how a flip-flop works.

There are four types of flip-flops:
  1. SET-RESET flip-flop, aka R-S or S-R flip-flop
  2. T-type flip-flop, aka toggle flip-flop
  3. D-type flip-flop, aka data or delay flip-flop
  4. J-K type flip-flop, aka J-K flip-flop

Here is an example of your basic 7476 J-K flip-flop:
Learn what happens to the Q and /Q outputs when a CLK signal is present for the four possible combinations of J and K inputs.
Learn what happens to the Q and /Q outputs when a low signal is applied to the S and R inputs.

1617587805210.png

Check out the AAC online tutorials
https://www.allaboutcircuits.com/textbook/digital/chpt-10/digital-logic-with-feedback/
 
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