# Edge detection using Combinatorial Logic

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#### ravics

Is there a way to design an edge detection digital circuit without using Sequential logic?

#### cent24.3

##### Member level 2
Hi ravics,

Sure : just an RC cell and a schmitt trigger.

ravics

### ravics

Points: 2

#### ravics

Thanks. Any way to implement using VHDL?

#### xtcx

I think you can use an Xor gate logic to detect the edges.

Code:
Begin

A_bar <= not (A) after 2 ns;

Y <= A_bar XOR A;
Your difference will be detected by the XOR gate. Resulting output will show an impulse whenever you get +ve and -ve edges.
If this is what you expect....You can simulate this for accurate results.

Points: 2

Points: 2