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Altera_Forum
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10 years ago

Undefined output

Hi I have asked to write compare machine which compare 2 numbers with 4 bits. I made it by ussing XOR. My outputs dont react to the change in the inputs, they undefined. The inputs works wel...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

Dont post images, post the actual code.

The problem probably occurs because you have a local variable i, and a while loop. The variable is probably gets to -1 on the first iteration and then the code is never executed again.

But the main problem with the code is that while loops are not synthesisable. You will need to change the code to remove the loops.