Intel® Quartus® Prime Software
Intel® Quartus® Prime Design Software, Design Entry, Synthesis, Simulation, Verification, Timing Analysis, System Design (Platform Designer, formerly Qsys)
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'after' in Timing Simulation tool

Altera_Forum
Honored Contributor II
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I'm create a simple program that simply delays the clock in 10ns. 

 

I used: 

 

------------------------------------------------------------ 

LIBRARY ieee; 

USE ieee.std_logic_1164.all; 

USE ieee.std_logic_arith.all; 

USE ieee.std_logic_unsigned.ALL; 

------------------------------------------------------------ 

ENTITY delay_clock IS 

PORT ( clk : IN BIT; 

clk_no_delay : OUT BIT; 

clk_delay : OUT BIT); 

END delay_clock; 

------------------------------------------------------------ 

ARCHITECTURE test OF delay_clock IS 

BEGIN 

clk_no_delay <= clk; 

clk_delay <= clk after 10ns; 

--clk_delay <= '1'; 

END test; 

 

But, when I simulate this in Quartus, the delay isn't 10 ns, why ??? 

 

Thank you, 

 

Rester
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Altera_Forum
Honored Contributor II
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IIRC, the quartus simulator only does gate level simulations, not code level. Therefore the "after" keyword is thrown away during synthesis as it has no meaning in real hardware. 

 

You will have to use modelsim to see this working.
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