@Stefan Schippers what should be filled in value field of code.sym?

code.sym

is a symbol that copies whatever in the

value

attribute to the spice netlist. It is used to embed spice commands, model includes and everything that is best described as netlist code into the final netlist. When selecting such a code element and pressing 'q' it is best to set the attribute to '`value`' so everything you type goes to the value attribute, without having to care about using quotes.

@Stefan Schippers do code.sym and code_shown.sym have same purpose? I get the following error evrytime when I try to simulate, "child process exited abnormally"

yes the two are identical, the second shows the value attribute in the schematic. If there is too much text in the value attribute it's better to replace code_shown.sym with code.sym

@Stefan Schippers how to rectify this? Note: No compatibility mode selected! Circuit: ** sch_path: /home/bn/.xschem/xschem_sky130/untitled.sch Error: unknown subckt: xm1 vout vin 0 0 sky130_fd_pr__nfet_01v8 l=0.15 w=1 nf=1 ad={int((nf+1)/2)*w/nf*0.29} as={int((nf+2)/2)*w/nf*0.29} pd={2*int((nf+1)/2)*(w/nf+0.29)} ps={2*int((nf+2)/2)*(w/nf+0.29)} nrd={0.29/w} nrs={0.29/w} sa=0 sb=0 sd=0 mult=1 m=1 Simulation interrupted due to error! Error: there aren't any circuits loaded.

to simulate any circuit you must provide a .lib that points to the spicemodels, usually:

.lib /path/to/share/pdk/sky130A/libs.tech/ngspice/sky130.lib.spice tt

the exact path above depends on your open_pdks installation