+ It is possible to insert a symbol by referencing a generator script instead of a .sym file. + When inserting the symbol select the All checkbox to see all files , select the generator script, + then in the File/Search textbox add two parenthesis () (or put required parameters in + between, like (buf)) +
+
+
+ The symbolgen generator in this example takes either a (buf) or a (inv) parameter
+ to generate a buffer or an inverter, respectively. If no parameters are given (empty parentheses) a buffer
+ is generated.
+ In this example a tcl script is used, you can use any language you like.
+
+#!/bin/sh
+# the next line restarts using wish \
+exec tclsh "$0" "$@"
+
+set arg1 [lindex $argv 0]
+if { $arg1 eq {inv}} {
+puts {v {xschem version=3.1.0 file_version=1.2}
+K {type=subcircuit
+verilog_primitive=true
+vhdl_primitive=true
+vhdl_format="@@Y <= not @@A after 90 ps;"
+verilog_format="assign #90 @@Y = ~@@A ;"
+format="@name @pinlist @symname ROUT=@ROUT"
+template="name=x1 ROUT=1000"
+schematic=inv_ngspice.sch}
+L 4 -40 0 -20 0 {}
+L 4 -20 -20 20 0 {}
+L 4 -20 -20 -20 20 {}
+L 4 -20 20 20 0 {}
+L 4 30 -0 40 -0 {}
+B 5 37.5 -2.5 42.5 2.5 {name=Y dir=out }
+B 5 -42.5 -2.5 -37.5 2.5 {name=A dir=in }
+A 4 25 -0 5 180 360 {}
+T {@symname} -47.5 24 0 0 0.3 0.3 {}
+T {@name} 25 -22 0 0 0.2 0.2 {}
+T {Y} 7.5 -6.5 0 1 0.2 0.2 {}
+T {A} -17.5 -6.5 0 0 0.2 0.2 {}
+T {ROUT=@ROUT} -25 -42 0 0 0.2 0.2 {}
+}
+} else {
+puts {v {xschem version=3.1.0 file_version=1.2}
+K {type=subcircuit
+verilog_primitive=true
+vhdl_primitive=true
+vhdl_format="@@Y <= @@A after 90 ps;"
+verilog_format="assign #90 @@Y = @@A ;"
+format="@name @pinlist @symname ROUT=@ROUT"
+template="name=x1 ROUT=1000"
+schematic=buf_ngspice.sch}
+L 4 20 0 40 0 {}
+L 4 -40 0 -20 0 {}
+L 4 -20 -20 20 0 {}
+L 4 -20 -20 -20 20 {}
+L 4 -20 20 20 0 {}
+B 5 37.5 -2.5 42.5 2.5 {name=Y dir=out }
+B 5 -42.5 -2.5 -37.5 2.5 {name=A dir=in }
+T {@symname} -47.5 34 0 0 0.3 0.3 {}
+T {@name} 25 -22 0 0 0.2 0.2 {}
+T {Y} 7.5 -6.5 0 1 0.2 0.2 {}
+T {A} -17.5 -6.5 0 0 0.2 0.2 {}
+T {ROUT=@ROUT} -25 -42 0 0 0.2 0.2 {}
+}
+}
+
+ + The generators/test_symbolgen.sch is a test schematic that places two instancs of this + symbol generator, one as symbolgen(buf) and one as symbolgen(inv). + The schematic implementations of these symbols are defined by the generator using a schematic + attribute. The buffer will use buf_ngspice.sch and the inverter will + use inv_ngspice.sch, these reused example schematics are present in + the ngspice/ directory. +
+
+ + The following is the extracted netlist from this example: +
++** sch_path: /home/schippes/xschem-repo/trunk/xschem_library/generators/test_symbolgen.sch +**.subckt test_symbolgen +x1 IN_INV IN symbolgen_inv ROUT=1200 +x3 IN_BUF IN symbolgen_buf ROUT=1200 +C1 IN_BUF 0 100f m=1 +C2 IN_INV 0 100f m=1 +**** begin user architecture code + + +.param vcc=1.8 +Vin in 0 pwl 0 0 10n 0 10.1n 1.8 20n 1.8 20.1n 0 +.control + save all + tran 0.2n 30n uic + write test_symbolgen.raw +.endc + + +**** end user architecture code +**.ends + +* expanding symbol: symbolgen(inv) # of pins=2 +** sym_path: /home/schippes/xschem-repo/trunk/xschem_library/generators/symbolgen +** sch_path: /home/schippes/xschem-repo/trunk/xschem_library/ngspice/inv_ngspice.sch +.subckt symbolgen_inv Y A ROUT=1000 +*.ipin A +*.opin Y +B1 net1 0 V = 'VCC/2*(1-tanh((V(A1)-VCC/2)*100))' +R1 Y1 net1 'ROUT' m=1 +C1 A1 0 8f m=1 +C2 Y1 0 8f m=1 +V1 Y Y1 0 +.save i(v1) +V2 A1 A 0 +.save i(v2) +.ends + + +* expanding symbol: symbolgen(buf) # of pins=2 +** sym_path: /home/schippes/xschem-repo/trunk/xschem_library/generators/symbolgen +** sch_path: /home/schippes/xschem-repo/trunk/xschem_library/ngspice/buf_ngspice.sch +.subckt symbolgen_buf Y A ROUT=1000 +*.ipin A +*.opin Y +B1 net1 0 V = 'VCC/2*(1+tanh((V(A1)-VCC/2)*100))' +R1 Y1 net1 'ROUT' m=1 +C3 Y1 0 8f m=1 +C1 A1 0 4f m=1 +V1 Y Y1 0 +.save i(v1) +V2 A1 A 0 +.save i(v2) +.ends + +.end ++
+ This approach allows to create polymorphic symbols. Multiple parameters may be given to the generator script, + like symbolgen(inv,hv,100). Xschem will call the symbolgen script with the following command: + symbolgen inv hv 100 and take the standard output from the script as the symbol + file to load and display. +
+