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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
10 years ago

Help with Creating delay to signals

I have written a simple program just to get a Clow how to do a slight delay to a signal.

Entity delay is

Port(sw: in std_logoc;

X: out std_logic_vectot(0 to 15);

Y: out std_logoc

);

End entity;

Architecture behave of delay is

Signal x1 : std_logic_vector(0 to 15);

Signal y1 : std_logic;

Begin

Process(sw)

Begin

If sw='1' then

y1<='1';

x1(0 to 3)<="1111"; - - I want to delay this for a few ns

Else

y1<='0';

x1(0 to 3)<="0000";

End if ;

End process;

X<=x1;

Y<=y1;

End;

I have tried to write things like:

"After 2ns"

Or

"transport "1111" after 2ns"

But in the wave for I didn't see any chance

Please halp

If you can I want to now how to see this in wave for in quartus

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    10 years ago

    after N ns is only meant for simulation, it is not synthesisable.

    For delays, you will have to use the system clock and some delay machanism (like a counter and enable) to get this to work. But why do you only want a few ns delay? unless you have a very fast clock, that wont be acheiveable. And smacks of poor timing relationships in your design.