From c317fdd025fab26e9564b1117d278ffd7e60b360 Mon Sep 17 00:00:00 2001
From: StefanSchippers <69359491+StefanSchippers@users.noreply.github.com>
Date: Mon, 8 Jan 2024 16:16:36 +0100
Subject: [PATCH] Created Use an existing spice text file for a subcircuit
 (markdown)

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 ...isting-spice-text-file-for-a-subcircuit.md | 51 +++++++++++++++++++
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 create mode 100644 Use-an-existing-spice-text-file-for-a-subcircuit.md

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+If you have for example the following definition in a file, say `symbol_include.cir`:
+```
+* example of a subcircuit contained in a file
+
+.subckt symbol_include Z VCC VSS
++ A B C W=10 L=1
+...
+...
+.ends
+```
+
+You can use this file to get the spice netlist port order:
+
+In the following testbench:
+
+![1](https://github.com/StefanSchippers/xschem/assets/69359491/17ef7c28-9167-4507-8898-26e01dbe989a)
+
+the symbol is defined as follows:
+
+![2](https://github.com/StefanSchippers/xschem/assets/69359491/db2f6c2b-3a4f-4a1b-bb76-861d13c6b964)
+
+When netlisting the testbench the port order (the @pinlist in the `format` string)
+of the `x1` instance call will match the order in the file `symbol_include.cir`:
+```
+** sch_path: /home/schippes/.xschem/xschem_library/symbol_include/tb_symbol_include.sch
+**.subckt tb_symbol_include XZ XVSS XVCC XC XB XA
+*.opin XZ
+*.ipin XVSS
+*.ipin XVCC
+*.ipin XC
+*.ipin XB
+*.ipin XA
+x1 XZ XVCC XVSS XA XB XC symbol_include
+**.ends
+
+* expanding   symbol:  symbol_include.sym # of pins=6
+** sym_path: /home/schippes/.xschem/xschem_library/symbol_include/symbol_include.sym
+.include symbol_include.cir
+.end
+```
+
+A final note, the `spice_sym_def` does not necessarily need to use a .include line. You can directly define the subcircuit:
+```
+spice_sym_def="
+.subckt symbol_include Z VCC VSS
++ A B C
+...
+...
+.ends
+"
+```
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