diff options
| -rw-r--r-- | .gitignore | 3 | ||||
| -rw-r--r-- | README.md | 23 | ||||
| -rw-r--r-- | examples/rc_lp.cir | 5 | ||||
| -rw-r--r-- | examples/rc_lp.py | 25 |
4 files changed, 50 insertions, 6 deletions
@@ -1,4 +1,5 @@ -# ngspice output — regenerate by running the sims +# simulation output — regenerate by running the sims +results/ *.raw *.raw.tmp @@ -1,8 +1,9 @@ -# kisim — run KiCad schematics in ngspice from Python +# kisim — run KiCad schematics or plain netlists in ngspice from Python `kisim.py` is a single-file simulation framework with no project knowledge. It: -1. exports a `.kicad_sch` to a SPICE netlist with `kicad-cli`, +1. exports a `.kicad_sch` to a SPICE netlist with `kicad-cli` (or takes a plain + ngspice netlist — `.cir`/`.spice`/`.net` — and uses it as-is), 2. edits the netlist (instance parameters, source waveforms, regex substitutions), 3. runs `ngspice -b`, and 4. hands the results back as numpy arrays addressed by the schematic's own net @@ -26,7 +27,8 @@ micromamba run -n kicad_work python my_sim.py Required on the system (not in the env): -- `kicad-cli` — schematic → SPICE netlist export (KiCad ≥ 7; developed on 10.0.6) +- `kicad-cli` — schematic → SPICE netlist export (KiCad ≥ 7; developed on 10.0.6). + Only needed for `.kicad_sch` inputs. - `ngspice` — the simulator (developed on ngspice-47) ## Usage @@ -49,8 +51,19 @@ r.plot(["+28V", "i(V1)", "Q2:power"]) using for big vendor models, where thousands of internal nodes make huge, slow raw files. +## Example + +`examples/` is a small runnable demo: + +- `rc_lp.cir` — a plain ngspice netlist: 5 V step into 1 kΩ + 100 nF +- `rc_lp.py` — runs it with kisim and plots V(in)/V(out) + +```sh +micromamba run -n kicad_work python examples/rc_lp.py +``` + ## Notes -- `results/*.raw` and regenerated `results/*.cir` files are gitignored; they - are rebuilt by running the sims. +- `results/` directories (sim output, plots) are gitignored; rebuilt by running + the sims. - Initially developed for the ASPECT+ payload board sims (2026). diff --git a/examples/rc_lp.cir b/examples/rc_lp.cir new file mode 100644 index 0000000..58d1f57 --- /dev/null +++ b/examples/rc_lp.cir @@ -0,0 +1,5 @@ +* RC low-pass: 5 V step into 1 kohm + 100 nF +V1 vin 0 PWL(0 0 1n 5) +R1 vin vout 1k +C1 vout 0 100n +.end diff --git a/examples/rc_lp.py b/examples/rc_lp.py new file mode 100644 index 0000000..0a79b60 --- /dev/null +++ b/examples/rc_lp.py @@ -0,0 +1,25 @@ +#!/usr/bin/env python3 +"""Example: run a plain ngspice netlist with kisim -- no KiCad involved. + + micromamba run -n kicad_work python examples/rc_lp.py +""" +import sys +from pathlib import Path + +sys.path.insert(0, str(Path(__file__).resolve().parents[1])) + +import numpy as np + +from kisim import KiSim + +sim = KiSim("rc_lp.cir", tran="1u 2m") # .cir input: used as-is, no kicad-cli +r = sim.run() # -> results/run.cir + run.raw (cached) + +tau = 1e3 * 100e-9 # R1 * C1 +vout = r.v("vout") +print(f"5 V step into 1 kohm + 100 nF: tau = {tau * 1e6:.0f} us") +print(f"V(vout) at 1 tau: {np.interp(tau, r.t, vout):.3f} V (1 - 1/e of 5 V)") +print(f"V(vout) settled: {vout[-1]:.3f} V") + +r.plot(["vin", "vout"], title="RC low-pass: 5 V step", file=sim.workdir / "rc_lp.png") +print("plot:", sim.workdir / "rc_lp.png") |