eldo_user

Eldo Control Language
Defining and Running Simulations
set tprop=0 powercons=0 res=0
res = simulation
+ (name="sim_dir/tprop.cir", log="sim_dir/tprop.log", args="-silent -
nowdb",
+ tran_options(),
+ measure_trop(cload_val=1.5p, signal="dff_out"),
+ tprop=@tp, powercons=@avgivdd))
if (res.simu_status == 0)
fprint(stdout, "tprop: %.5g power_cons: %.5g\n", tprop, powercons)
else
fprint(stdout, "Simulation failed\n")
endif
In the example above, the simulation is built by instantiating two testbenches, namely
tran_options and measure_tprop, which were previously shown as examples (see “Testbenches”
on page 809). The tran_options testbench has no parameters. The measure_tprop testbench is
passed several arguments, which override the default values provided in its definition. The
cload_val parameter takes the value 0.5p (0.5×10 −12 ), and the signal parameter is set to dff_out.
The trise parameter is not passed, thus it will take its default value, 10n.
The tprop and powercons scalar variables (explained in “Variables” on page 821) are used to
store the values of the tp and avgivdd quantities computed as results of the simulation (they are
labels of the extract commands contained in the measure_tprop testbench).
Normally, the order of appearance of commands or element descriptions in the final netlist is
not important. Note, however, that the testbenches defined within the simulation command are
appended in the same order as they appear in the simulation command.
Based on the example above, the fprint function generates the resulting netlist, tprop.cir, as
follows:
*tran_options testbench :
.option eps=1e-8 hmax=10p reltol=1e-7 gear
*measure_tprop testbench :
.tran 0 10n
cload dff_out gnd 1.5p
VD D gnd PULSE 0V 1.8V 0n 10n 10n 50n 100n
.extract tran label=tp xup(V(dff_out))-xup(V(D))
.extract tran label=avgivdd avg(i(vdd))
And the process would be launched as follows:
eldo -silent -nowdb -i sim_dir/tprop.cir > sim_dir/tprop.log &
This previous example illustrates the first use model: indeed, the local netlist must not be empty
for the simulation to succeed; it must contain dff_out and gnd nodes, a D input, and a VDD
power supply.
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Eldo® User's Manual, 15.3