.. include:: /project-links.txt
.. include:: /abbreviation.txt



.. getthecode:: kicad-example.py
    :language: python3
    :hidden:


==============================
 Kicad Netlist Parser Example
==============================

This example shows how to read a netlist generated from the |Kicad|_ Schematic Editor.

This example is copied from Stafford Horne's Blog:
 * http://stffrdhrn.github.io/electronics/2015/04/28/simulating_kicad_schematics_in_spice.html
 * https://github.com/stffrdhrn/kicad-spice-demo

.. note:: The netlist must be generated using numbered node. Subcircuit elements must have a
          reference starting by *X* and a value corresponding to the subcircuit's name.


.. image:: kicad-pyspice-example.sch.svg
    :align: center

The netlist generated by Kicad is the following:

.. getthecode:: kicad-pyspice-example.cir
    :language: py3


.. code-block:: py3

    
    
    from pathlib import Path
    
    import matplotlib.pyplot as plt
    
    
    import PySpice.Logging.Logging as Logging
    logger = Logging.setup_logging()
    
    
    from PySpice.Doc.ExampleTools import find_libraries
    from PySpice.Probe.Plot import plot
    from PySpice.Spice.Library import SpiceLibrary
    from PySpice.Spice.Netlist import SubCircuitFactory
    from PySpice.Spice.Parser import SpiceParser
    from PySpice.Unit import *
    
    
    libraries_path = find_libraries()
    spice_library = SpiceLibrary(libraries_path)
    
    

We implement the *PowerIn*, *Opamp*, *JackIn* and *JackOut* elements as subcircuit.

.. code-block:: py3

    
    class PowerIn(SubCircuitFactory):
    
        __name__ = 'PowerIn'
        __nodes__ = ('output_plus', 'ground', 'output_minus')
    
    
        def __init__(self):
    
            super().__init__()
    
            self.V('positive', 'output_plus', 'ground', 3.3@u_V)
            self.V('negative', 'ground', 'output_minus', 3.3@u_V)
    
    
    class Opamp(SubCircuitFactory):
    
        __name__ = 'Opamp'
        __nodes__ = ('output',
                     'input_negative', 'input_positive',
                     'power_positive', 'power_negative')
    
    
        def __init__(self):
    
            super().__init__()
    
            self.X('opamp', 'LMV981',
                   'input_positive', 'input_negative',
                   'power_positive', 'power_negative',
                   'output',
                   'NSD')
    
    
    class JackIn(SubCircuitFactory):
    
        __name__ = 'JackIn'
        __nodes__ = ('input', 'x', 'ground')
    
    
        def __init__(self):
    
            super().__init__()
    
            self.V('micro', 'ground', 'input', 'AC SIN(0 0.02 440)')
    
    
    class JackOut(SubCircuitFactory):
    
        __name__ = 'JackOut'
        __nodes__ = ('output', 'x', 'ground')
    
    
        def __init__(self):
    
            super().__init__()
    
            self.R('load', 'output', 'x', 10@u_Ω)
    
    

We read the generated netlist.

.. code-block:: py3

    directory_path = Path(__file__).resolve().parent
    kicad_netlist_path = directory_path.joinpath('kicad-pyspice-example', 'kicad-pyspice-example.cir')
    parser = SpiceParser(path=str(kicad_netlist_path))
    

We build the circuit and translate the ground (5 to 0).

.. code-block:: py3

    circuit = parser.build_circuit(ground=5)
    

We include the operational amplifier module.

.. code-block:: py3

    circuit.include(spice_library['LMV981'])
    

We define the subcircuits.

.. code-block:: py3

    for subcircuit in (PowerIn(), Opamp(), JackIn(), JackOut()):
        circuit.subcircuit(subcircuit)
    
    # print(str(circuit))
    

We perform a transient simulation.

.. code-block:: py3

    simulator = circuit.simulator(temperature=25, nominal_temperature=25)
    analysis = simulator.transient(step_time=100@u_us, end_time=3@u_ms)
    
    figure = plt.figure(1, (20, 10))
    plot(analysis['2']) # JackIn input
    plot(analysis['7']) # Opamp output
    plt.legend(('Vin [V]', 'Vout [V]'), loc=(.8,.8))
    plt.grid()
    plt.xlabel('t [s]')
    plt.ylabel('[V]')
    
    plt.tight_layout()
    plt.show()
    


.. image:: kicad-example.png
    :align: center