General Technical Discussion

[danbo.liang]

Hi All,

in my design, there are 2 similar signals, one is ssn[2] and another is ssn_2, the port define is below:

input [2:0] ssn;

output       ssn_2;

when synthesize, ISE will report error "the net ssn_2 is not found", why?

[drjohnsmith]

Hi

1001 resons,

    the most likely I gues is that  the signal is not used in th edesign,

               and is optimised away, a fairly common mistake.

It does raise the question of the naming convention yoru using,

     try changing ssn_2 to ssn_b

if ssn_b is reported as missing, its benn optimised away,

    if it reports ssn_2, oops....

[danbo.liang]

Hi

Actually, the signal is used.

After change ssn_2 to ssn_b, it is OK.

So I doubt that ssn_2 and ssn[2] are treated as same in ISE naming convention.

[drjohnsmith]

an interesting quirk

but at least you have a work around.