eldo_user

Simulator Compatibility
Troubleshooting the Spectre to Eldo Flow
Spectre Node and Device Names
When Eldo is using a Spectre netlist as input, and the netlist contains an internal node and a
device with the same name, it is impossible for Eldo to distinguish between these. When Eldo
analyses a subcircuit in the Spectre netlist, each element is attempted to be converted, without
knowing if it is a node name or a device name. This can lead to plots not being performed as
expected, because Eldo does not know what kind of plot is required (I or V for example).
If topsp, the Spectre input file, contains a subcircuit instance named x1, and the SPICE
command file, cmd.cir, contains:
.plot dc v(x1.c1)
then c1 must be an internal node name as a voltage plot is requested.
However, if cmd.cir contains:
.plot dc I(x1.c1)
then c1 must be a device name as a current plot is requested.
When Eldo is using a Spectre netlist as input, Eldo does not initially know the kind of plot
requested (I or V). Therefore, when Eldo analyses x1.c1, each element is attempted to be
converted; x1.c1 is mapped to xx1.yy, where yy can be cc1 if there was a capacitor named c1 in
that subcircuit in the Spectre design, or c1 if there was no capacitor named c1.
So if the following is specified:
.plot dc v(x1.c1)
it is equivalent to .plot dc v(xx1.cc1) if c1 is defined as a device, no matter if it is a node name
or not. In this case, the plot is not performed.
Error Messages
The Spectre to Eldo converter logs the line number where a conversion error occurs. Some
example error messages and full descriptions are provided in Table 5-6.
Table 5-6. Spectre Conversion Error Messages
Error Message
Code
5 Unable to open the temporary file
“a_name”.
Description
Eldo cannot create a temporary file
required to process the simulation. The file
contains the converted Spectre design and
the SPICE command file, if there is one.
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Eldo® User's Manual, 15.3