HELP: How to use clocks to sync circuits?

[Vaishnav S Menon]

Hello!

I'm trying to make a calculator out of logic gates, and although I think I've got hold of the adders, subtractors, etc, I can't figure out how to use clocks to sync tasks.

For example, say I have to add 5 numbers one after the other (for internal reasons, not actual user input). How do I use a clock and control it so that the adder performs the first addition, stores the result to a register, then takes input of the second addition from the register and from some secondary outside "input source", and continue so on?

Sorry if my question is a tad bit unclear, I tried to make it as clear as possible.

Thank you!

PS - This is my first electronics project

 

[chuckey]

I have never done this but the way I would attempt it is as follows. The thing to remember is to only shift/read data when it has settled, so I would think a series of time shifted clocks would be handy or else you need a clock divider/shift register and do one action per one clock pulse.
So set output register to 0,which is also an input to adder, clock input number1 into SR bistables. wait for data to settle, clock output of adder into output shift register (now contains number 1 +0).
Now clock second number into SRs, wait for data to settle, clock output of adder to output register (now contains number 1+2).
Food for thought?
Frank

 

[andre_luis]

You are willing to perform what is called a synchronous design and it is recommended you take a research on the subject 'state machines'. As it is your first design and the purpose is certainly learning, you will do manually the steps of the design instead using a tool for that.

Basically, at the end of each functional block ( adder, multiplexer, etc... ) you need to insert a register that will store the last result, and the design itself will consist on determine the logic for the timing for these clocks ( or phases ).