a pull up can describe like this:
wire (weak1,weak0) out = 1'b1;
Verictor a écrit :
> Assuming I have this tristate open drain buffer defined as (my library
> has this buffer)
> assign out = en ? 1'bz : 1'b0;
> Now I want to simulate this buffer. The way I try is to connect two
> such buffers, e.g.,
> tribuffer tri1(.out(out), .en(en1));
> tribuffer tri2(.out(out), .en(en2));
> tribuffer is the module name and I define en1 and en2 as regs and out
> as tri. Outlining all combinations of en1 and en2, I can only get out
> is either 0 or z. Never seen out = 1.
> My question is that how can I specify out is a pullup wire (or maybe
> other types) to obtain 1? Or if this way is not a doable way to test
> it, what is the better way to test it?