Z doesn't exist in alliance VBE format try this my_bus: BLOCK( en='1' ) begin output <= input; end block; Vaclav Peroutka wrote: > Did not work "output <= input when en = '1' else 'Z'" ? > > Vaclav > > GIIE wrote: > > > Hello sir, > > > > Pls could you help me with the following: > > > > 1. I do not know if its possible with Alliance, but I would like to > > implement a Tri-State Buffer. > > For example, I have the following truth-table: > > > > en input Output > > ------------------------------ > > 0 0 Z > > 0 1 Z > > 1 0 1 > > 1 1 1 > > > > My question is about the 'Z' output. How do I write the VHDL code to > > implement the 'Z' output. > >