ModelSim SE User's Manual - Electrical and Computer Engineering

Example 3 — Mixed-HDL design
First, create three VCD files, one for each module:
% cd ~/modeltech/examples/mixedHDL
% vlib work
% vlog cache.v memory.v proc.v
% vcom util.vhd set.vhd top.vhd
% vsim top
VSIM 1> vcd dumpports -file proc.vcd /top/p/*
VSIM 2> vcd dumpports -file cache.vcd /top/c/*
VSIM 3> vcd dumpports -file memory.vcd /top/m/*
VSIM 4> run 1000
VSIM 5> quit -f
Next, rerun each module separately, using the captured VCD stimulus:
% vsim -vcdstim proc.vcd proc -do "add wave /*; run 1000"
VSIM 1> quit -f
% vsim -vcdstim cache.vcd cache -do "add wave /*; run 1000"
VSIM 1> quit -f
% vsim -vcdstim memory.vcd memory -do "add wave /*; run 1000"
VSIM 1> quit -f
Replacing instances with output values from a VCD file
Using extended VCD as stimulus UM-459
Replacing instances with output values from a VCD file lets you simulate without the
instance’s source or even the compiled object. The general procedure includes two steps:
1 Create VCD files for one or more instances in your design using the vcd dumpports
command (CR-295). If necessary, use the -vcdstim switch to handle port order problems
(see below).
2 Re-simulate your design using the -vcdstim = argument to vsim
(CR-373). Note that this works only with VCD files that were created by a ModelSim
simulation.
Example
In the following example, the three instances /top/p, /top/c, and /top/m are replaced in
simulation by the output values found in the corresponding VCD files.
First, create VCD files for all instances you want to replace:
vcd dumpports -vcdstim -file proc.vcd /top/p/*
vcd dumpports -vcdstim -file cache.vcd /top/c/*
vcd dumpports -vcdstim -file memory.vcd /top/m/*
run 1000
Next, simulate your design and map the instances to the VCD files you created:
vsim top -vcdstim /top/p=proc.vcd -vcdstim /top/c=cache.vcd
-vcdstim /top/m=memory.vcd
ModelSim SE User’s Manual