Answers Database

Foundation F1.4. Logic simulator: Bus ordering reversed after bus has been flattened, then combined


Record #3205

Product Family:  Software

Product Line:  Aldec

Problem Title:
Foundation F1.4. Logic simulator: Bus ordering reversed after bus has
been flattened, then combined



Problem Description:
Keywords: Foundation, F1.4, Simulation, Bus, Flatten, Combine

Urgency: Standard


When simulating a bus signal, if it is first flattened from the
menu selection (Signal->Bus->Flatten) and then recombined
(Signal->Bus->Combine), the bit order is reversed. (i.e. the
most significant bit becomes the least significant bit, and the
least significant bit becomes the most significant bit).

This will produce incorrect simulation results.


Solution 1:

It is best to not use the FLATTEN and COMBINE features during
the simulation. Instead, use the Expand/Collapse Buses Button
in the waveform viewer. (the icon directly under OPTIONS menu)
to view the individual bits of the bus.

In case the bit order has been switched, you can restore the correct order by se
lecting:

Signal -> Bus -> Change Direction



Solution 2:





End of Record #3205