help with modelsim error (delay in signal assignment must be ascending)

[ra]

Hi,
I have a schematic where N components output each one a reset signal,
which is given in input to one other component. The line connecting
the resets is something like:

reset <= res_1 or res_2 or res_3 or ... or res_N;

This synthetize fine, but modelsim gives me the following error on the
line above:

Error: router_test_arch.vhd(709): Delay in signal assignment must be
ascending.

Can somebody tell me what to look for? I've no clue.....


RA

 

[Egbert Molenkamp]

I have the feeling that the error message has nothing to do with the line
you show.
This error message occurs when you assign to a signal something like:

y <= '0' after 10 ns,
'1' after 5 ns; -- time not ascending;

Correct is
y <= '1' after 5 ns,
'0' after 10 ns;

Egbert Molenkamp

 

[ra]

I would have understood that, but I'm not using explicitly any "after"
or "wait". Also, replacing the line I mentioned with just

reset <= res_1

solves the problem.

 

[Egbert Molenkamp]

Strange ..

Maybe you can remove (comment) parts of the description to find out when it
is wrong/right. You already did it with the or chain for the reset. Maybe
fine tuning can find the problem.
You may also send me the VHDL description. Maybe I see what the problem is.

Egbert Molenkamp