Dear All,
I’m trying to understand the application of transaction in scoreboard.
In the common usage, there are 2 agents.
one monitor samples DUT inputs and another monitor samples DUT outputs.
For reusability, one transaction taken in monitor, driver and scoreboard.
In scoreboard, generally, it is comparing between driver and monitor transaction.
From here I can’t understand how scoreboard compare driver’s transaction and monitor’s transaction.
For example, If I got a transaction
class trans extends uvm_sequence_item;
logic [15:0] dout;
rand bit [15:0] din;
rand bit ld, inc, rst_n;
...
endclass
Probably we can say monitor, driver and scoreboard will use “trans”. then in scoreboard trans would be used to compare between driver’s “trans” and monitor’s “trans” such as below in scoreboard,
...
trans ext_tr, out_tr;
forever begin
expfifo.get(exp_tr);
...
outfifo.get(out_tr);
...
if (out_tr.compare(exp_tr) begin
pass();
else
fail();
end
...
end
AS you can see “out_tr.compare(exp_tr)” I can’t understand how to compare between out_tr and exp_tr by using comapre method?
I assume that if I got the below transaction values in trans, and DUT has a behavior as "dout = din +2 ".
out_tr exp_tr
dout=('h50); dout;
din; din=('h48)
ld=('h1); ld=('h1);
inc=('h0); inc=('h0);
rst_n=('h1); rst_n=('h1);
If I ran out_tr.compare(exp_tr) then probably it was made an mismatch message If I correctly understand compare method.
How does compare method work between out_tr and exp_tr?