@Stefan Schippers, actually, I'm getting stuck with parameter substitution in a hierarchical schematic. xschem seems to substitute the values in the schematic, but not in the subcircuit expansion of the ngspice netlist.

@Christoph Maier parameter substitution in the schematic is only done visually. if a mos uses the

@w

text in its symbol and

w=wn

is set in the transistor placement and

wn=wnn

is set in the nand gate and

wnn=4u

is set in the flip flop that uses the nand gate, if you descend down to the transistor it will show 4u where @w is present in the symbol. substitution is not done in the netlist for 2 reasnos, the second one being fundamental: • all modern simulators handle parametrized subcircuits • you only have one subcircuit for a nand gate and you might have many placements each with different sizing (if the nand is parametric). You can not replace the parametrized dimensions with numbers, unless you flatten the nand gate and place bare transistors, and do this for all hierarchy levels containing the nand gate if they propagate parameters.