What are the differences between std_logic and std_ulogic?

[rajakash]

hi..

wats the difference b/t std_logic and std_ulogic..

 

[shawndaking]

Re: difference

std_uolgic is unresolved - i.e don't have resulution function like std_logic.

for eample if 2 sources drive the signal then in std_ulogic its impossible condition while std_logic will resolves the situation as 'x'.

 

[salma ali bakr]

Re: difference

std_ulogic isn't recommended, unless you're sure that only one source drives your signal

if not, then you must use std_logic...since it's a resolved type..which means that it has a function that solves the "quarrel" between the values of different driving signals and gives you a final signal value (no need to make your own resolution function)