Verilog $time affectation appears wrong in Questasim

[Johanexpleo]

Hi all,

I have an issue in my Questasim simulation using verilog MRAM model.
Timescale is define as `timescale 1ns/1ps

I try to observe an assigned time signal as follow; data_time <= $realtime; in Questasim.
At the 3 us, it appears as 3000 ps. Then the calculation made in the verilog model are wrong.

I tried to change the timescale to 1ps/1ps, the issue is solved BUT, my simulation is much too long.
I don't understand why the $time is not interpreted correctly in Questasim when using timescale 1ns/1ps.
When I add the line $display("%t", $realtime); in the code, the correct value is displayed in the transcript. (see attached image)

Why my data_time has a wrong unit during simulation?
Thanks for your help

 

[dave_59]

It would really help to show some code and what your calculation is expecting versus what you were actually seeing instead of just saying its "wrong".

Also see https://verificationacademy.com/forums/systemverilog/time-vs-realtime#reply-94096