Help me fix the LEDA violations! Thank you in advance!

[dongdong209]

When I use LEDA check my RTL codes, it reports many violations:

1. Flipflop with fixed value data input is detected.

2. Top level output ports is not registered.

I don't why. Please help me fix them. Or tell me some rules when we edit RTL codes to avoid the violations.

Thank you in advance. O(∩_∩)O~

 

[RBB]

Those probably aren't really problems.

1. This just means a D-flop's input is either a constant '1' or '0'. This can be common depending how you've coded somethings. I usually just take a quick look at the violating flop & see if I can remove the flop altogether, if not I just ignore the error.

2. Basically like it states that your outputs are not registered, i.e. not driven by flops. They are being driven by combinational logic. This may or may not be a problem. It depends on your design.