README.rst

skidl

SKiDL is a module that allows you to compactly describe the interconnection of electronic circuits and components using Python. The resulting Python program performs electrical rules checking for common mistakes and outputs a netlist that serves as input to a PCB layout tool.

• Free software: MIT license
• Documentation: http://xesscorp.github.io/skidl
• User Forum: https://github.com/xesscorp/skidl/discussions

Features

• Has a powerful, flexible syntax (because it is Python).
• Permits compact descriptions of electronic circuits (think about not tracing signals through a multi-page schematic).
• Allows textual descriptions of electronic circuits (think about using diff and git for circuits).
• Performs electrical rules checking (ERC) for common mistakes (e.g., unconnected device I/O pins).
• Supports linear / hierarchical / mixed descriptions of electronic designs.
• Fosters design reuse (think about using PyPi and Github to distribute electronic designs).
• Makes possible the creation of smart circuit modules whose behavior / structure are changed parametrically (think about filters whose component values are automatically adjusted based on your desired cutoff frequency).
• Can work with any ECAD tool (only two methods are needed: one for reading the part libraries and another for outputing the correct netlist format).
• Can perform SPICE simulations (Python 3 only).
• Takes advantage of all the benefits of the Python ecosystem (because it is Python).

As a very simple example (see more in the blog), the SKiDL program below describes a two-input AND gate built from discrete transistors:

from skidl import *

# Create part templates.
q = Part("Device", "Q_PNP_CBE", dest=TEMPLATE)
r = Part("Device", "R", dest=TEMPLATE)

# Create nets.
gnd, vcc = Net("GND"), Net("VCC")
a, b, a_and_b = Net("A"), Net("B"), Net("A_AND_B")

# Instantiate parts.
gndt = Part("power", "GND")             # Ground terminal.
vcct = Part("power", "VCC")             # Power terminal.
q1, q2 = q(2)                           # Two transistors.
r1, r2, r3, r4, r5 = r(5, value="10K")  # Five 10K resistors.

# Make connections between parts.
a & r1 & q1["B C"] & r4 & q2["B C"] & a_and_b & r5 & gnd
b & r2 & q1["B"]
q1["C"] & r3 & gnd
vcc += q1["E"], q2["E"], vcct
gnd += gndt

generate_netlist()

And this is the output that can be fed to a program like KiCad's PCBNEW to create the physical PCB:

(export (version D)
  (design
    (source "/media/devb/Main/xesscorp/KiCad/tools/skidl/skidl/circuit.py")
    (date "05/11/2021 10:40 AM")
    (tool "SKiDL (1.0.0)"))
  (components
    (comp (ref #PWR1)
      (value GND)
      (footprint "No Footprint")
      (fields
        (field (name F0) #PWR)
        (field (name F1) GND))
      (libsource (lib power) (part GND))
      (sheetpath (names /top/16948080335112909674) (tstamps /top/16948080335112909674)))
    (comp (ref #PWR2)
      (value VCC)
      (footprint "No Footprint")
      (fields
        (field (name F0) #PWR)
        (field (name F1) VCC))
      (libsource (lib power) (part VCC))
      (sheetpath (names /top/10777333099431236833) (tstamps /top/10777333099431236833)))
    (comp (ref Q1)
      (value Q_PNP_CBE)
      (footprint "No Footprint")
      (fields
        (field (name F0) Q)
        (field (name F1) Q_PNP_CBE))
      (libsource (lib Device) (part Q_PNP_CBE))
      (sheetpath (names /top/5605641708446153824) (tstamps /top/5605641708446153824)))
    (comp (ref Q2)
      (value Q_PNP_CBE)
      (footprint "No Footprint")
      (fields
        (field (name F0) Q)
        (field (name F1) Q_PNP_CBE))
      (libsource (lib Device) (part Q_PNP_CBE))
      (sheetpath (names /top/3991298653620578089) (tstamps /top/3991298653620578089)))
    (comp (ref R1)
      (value 10K)
      (footprint "No Footprint")
      (fields
        (field (name F0) R)
        (field (name F1) R))
      (libsource (lib Device) (part R))
      (sheetpath (names /top/17650585640079795295) (tstamps /top/17650585640079795295)))
    (comp (ref R2)
      (value 10K)
      (footprint "No Footprint")
      (fields
        (field (name F0) R)
        (field (name F1) R))
      (libsource (lib Device) (part R))
      (sheetpath (names /top/11461493733231665754) (tstamps /top/11461493733231665754)))
    (comp (ref R3)
      (value 10K)
      (footprint "No Footprint")
      (fields
        (field (name F0) R)
        (field (name F1) R))
      (libsource (lib Device) (part R))
      (sheetpath (names /top/1249286041592970488) (tstamps /top/1249286041592970488)))
    (comp (ref R4)
      (value 10K)
      (footprint "No Footprint")
      (fields
        (field (name F0) R)
        (field (name F1) R))
      (libsource (lib Device) (part R))
      (sheetpath (names /top/7242640812520981502) (tstamps /top/7242640812520981502)))
    (comp (ref R5)
      (value 10K)
      (footprint "No Footprint")
      (fields
        (field (name F0) R)
        (field (name F1) R))
      (libsource (lib Device) (part R))
      (sheetpath (names /top/9932266607871614386) (tstamps /top/9932266607871614386))))
  (nets
    (net (code 1) (name A)
      (node (ref R1) (pin 1)))
    (net (code 2) (name A_AND_B)
      (node (ref Q2) (pin 1))
      (node (ref R5) (pin 1)))
    (net (code 3) (name B)
      (node (ref R2) (pin 1)))
    (net (code 4) (name GND)
      (node (ref #PWR1) (pin 1))
      (node (ref R3) (pin 2))
      (node (ref R5) (pin 2)))
    (net (code 5) (name N$1)
      (node (ref Q1) (pin 2))
      (node (ref R1) (pin 2))
      (node (ref R2) (pin 2)))
    (net (code 6) (name N$2)
      (node (ref Q1) (pin 1))
      (node (ref R3) (pin 1))
      (node (ref R4) (pin 1)))
    (net (code 7) (name N$3)
      (node (ref Q2) (pin 2))
      (node (ref R4) (pin 2)))
    (net (code 8) (name VCC)
      (node (ref #PWR2) (pin 1))
      (node (ref Q1) (pin 3))
      (node (ref Q2) (pin 3))))
)