Time delay

[Aliki]

Can anybody tell me how can I make a module within a design, to start
getting its input with a little delay (for instance a few nanoseconds.
I've tried the "after X ns" with no success.
Thank you in advance.

 

[Allan Herriman]

Can anybody tell me how can I make a module within a design, to start
getting its input with a little delay (for instance a few nanoseconds.
I've tried the "after X ns" with no success.
Thank you in advance.

"sig <= <whatever> after X ns;" will give you an inertial delay.

Try "sig <= transport <whatever> after X ns;" instead.


OTOH, you may have your simulator time resolution set too low
(coarse). Time delays less than the resolution get rounded down to
zero.

Regards,
Allan

 

[Mike Treseler]

Can anybody tell me how can I make a module within a design, to start
getting its input with a little delay (for instance a few nanoseconds.
I've tried the "after X ns" with no success.

Consider using a synchronous design with a clock input.
This allows you to think about logic description
while the place and route worries about adding
up gate delays to meet the fmax spec.

-- Mike Treseler