1 files changed, 137 insertions, 0 deletions
diff --git a/firmware/ltspice_plot.py b/firmware/ltspice_plot.py
new file mode 100755
index 0000000..38145d9
--- /dev/null
+++ b/firmware/ltspice_plot.py
@@ -0,0 +1,137 @@
+#!/usr/bin/env python3
+
+from matplotlib import pyplot as plt
+import numpy as np
+import ast
+import re
+import csv
+import math
+
+MULTIPLIERS = {
+    'a': 1e-18,
+    'f': 1e-15,
+    'p': 1e-12,
+    'n': 1e-9,
+    'u': 1e-6,
+    'µ': 1e-6,
+    'm': 1e-3,
+    'k': 1e3,
+    'M': 1e6,
+    'G': 1e9,
+    'T': 1e12,
+    'P': 1e15,
+    'E': 1e18,
+}
+
+def load_ltspice_csv(filename):
+    with open(filename) as f:
+        reader = csv.DictReader(f, delimiter='\t')
+        fieldnames = reader.fieldnames
+        return np.array([ [float(field) for field in line.values()] for line in reader ]), fieldnames
+
+def parse_unit(val, **units):
+    for unit, scale in units.items():
+        if val.endswith(unit):
+            val = val[:-len(unit)]
+            break
+    else:
+        scale = 1.0
+
+    if val[0] == '!':
+        val = '-'+val[1:]
+
+    try:
+        return float(val)*scale
+    except:
+        match = re.match(r'(-?[0-9]*(\.[0-9]+)?)([afpnuµmkMGTPE])', val)
+        if not match:
+            raise ValueError(f'Invalid value: {val}')
+
+        val, _, suffix = match.groups()
+        return float(val) * MULTIPLIERS[suffix] * scale
+
+def parse_range(text, sep='-', **units):
+    if text:
+        start, _, end = text.partition(sep)
+        return parse_unit(start, **units), parse_unit(end, **units) if end else math.inf
+    else:
+        return 0, math.inf
+
+def apply_style(ax):
+    ax.spines['top'].set_visible(False)
+    ax.spines['right'].set_visible(False)
+    ax.spines['bottom'].set_color('#08bdf9')
+    ax.spines['left'].set_color('#08bdf9')
+    ax.tick_params(axis='x', colors='#01769D')
+    ax.tick_params(axis='y', colors='#01769D')
+    ax.xaxis.label.set_color('#01769D')
+    ax.yaxis.label.set_color('#01769D')
+    ax.grid(color='#08bdf9', linestyle=':')
+
+
+if __name__ == '__main__':
+    import argparse
+    import os
+    parser = argparse.ArgumentParser()
+    parser.add_argument('input_txt', action='store', nargs='+', help='LTSpice .txt data export')
+    parser.add_argument('-o', '--output', help='Output SVG file. Defaults to <input file name>.svg.', default=None, nargs='?')
+    parser.add_argument('-s', '--span', default=None, help='Time span to plot, format: [time][unit]{-[time][unit]}')
+    parser.add_argument('-c', '--channels', default=[None], action='store', nargs='*', help='List of channels to plot. Comma-separated 0-based indices or signal names. Use multiple times for vertically-stacked subplots.')
+    parser.add_argument('-x', '--xlabel', default='$t\;(\mu s)$', help='Time axis label')
+    parser.add_argument('-y', '--ylabel', default=[None]*100, action='store', nargs='*', help='Y axis labels. Use multiple times for subplots.')
+    parser.add_argument('-r', '--yrange', default=[None]*100, action='store', nargs='*', help='Value ranges for y axes.  Use multiple times for subplots. Use ! instead of prefix minus sign.')
+    parser.add_argument('-t', '--timescale', default='1us', help='Time axis unit')
+    parser.add_argument('--subplot-title', default=[None]*100, action='store', nargs='*', help='Subplot titles')
+    parser.add_argument('-f', '--figure-size', default='8x6', help='Plot size in [x]x[y] inches')
+    args = parser.parse_args()
+
+    start, end = parse_range(args.span, s=1)
+    timescale = parse_unit(args.timescale, s=1)
+
+    inputs = []
+    for filename in args.input_txt:
+        data, fieldnames = load_ltspice_csv(filename)
+        data = data[(data[:,0] > start) & (data[:,0] < end)]
+        data[:,0] = (data[:,0] - start) / timescale
+        inputs.append((data, fieldnames))
+
+    fig, axs = plt.subplots(len(args.channels), 1, squeeze=False, sharex=True, figsize=parse_range(args.figure_size, sep='x'))
+    
+    for row, (ax, channelspec) in enumerate(zip(axs.flatten(), args.channels)):
+        channels = channelspec.split(',') if args.channels else range(0, 1000)
+
+        apply_style(ax)
+
+        n_plotted = 0
+        name_plotted = 'V(out)'
+        for k, (data, fieldnames) in enumerate(inputs):
+            for i, name in enumerate(fieldnames[1:], start=1):
+                if not any(x in channels for x in [i, f'{i}', f'{k}:{i}', f'{name}', f'{k}:{name}']):
+                    print(f'Not plotting channel {i} "{name}"')
+                    continue
+                print(f'Plotting channel {i} "{name}"')
+                ax.plot(data[:,0], data[:,i], color='#fe3ea0')
+                n_plotted += 1
+                name_plotted = name
+
+        if args.yrange[row]:
+            ax.set_ylim(parse_range(args.yrange[row], A=1, V=1))
+
+        if args.ylabel[row]:
+            ax.set_ylabel(args.ylabel[row])
+        else: # Guess label
+            unit = {'V': 'V', 'I': 'A'}[name_plotted[0]]
+            if n_plotted == 1:
+                ax.set_ylabel(f'${name_plotted}\;({unit})$')
+            else:
+                ax.set_ylabel(f'${name_plotted[0]}\;({unit})$')
+
+        if args.subplot_title[row] not in (None, '<none>'):
+            ax.set_title(args.subplot_title[row], color='#fe3ea0', fontname='Fredoka One')
+
+        outfile = args.output if args.output else os.path.splitext(args.input_txt[0])[0] + '.svg'
+        
+    if args.xlabel:
+        axs.flatten()[-1].set_xlabel(args.xlabel)
+    plt.tight_layout()
+    fig.savefig(outfile)