Don't care signals

[bittor]

Hello,
I want to do something like if ( signal_A=signal_B) then...
Where I want to have one of the signals with don't care. Then always
signal_A=signal_B. I tried to do this with types (X,U,-,etc...) but it
doesn't work.
Anyone can help me?
Thanks

 

[Tim Hubberstey]

bittor wrote:

Hello,
I want to do something like if ( signal_A=signal_B) then...
Where I want to have one of the signals with don't care. Then always
signal_A=signal_B. I tried to do this with types (X,U,-,etc...) but it
doesn't work.
Anyone can help me?

Comp.lang.vhdl FAQ, Part 1, section 4.2.9 "Don’t Cares" in VHDL

http://www.eda.org/comp.lang.vhdl/
--
Tim Hubberstey, P.Eng. . . . . . Hardware/Software Consulting Engineer
Marmot Engineering . . . . . . . VHDL, ASICs, FPGAs, embedded systems
Vancouver, BC, Canada . . . . . . . . . . . http://www.marmot-eng.com