5. Leflib API

sc_leflib.parse(path)

Parses LEF file.

Given a path to a LEF file, this function parses the file and returns a dictionary representing the contents of the LEF file. If there’s an error while reading or parsing the file, this function returns None instead.

Note that this function does not return all information contained in the LEF. The subset of information returned includes:

• LEF version

• Bus bit characters

• Divider characters

• Units

• Manufacturing grid

• Use min spacing

• Clearance measure

• Fixed mask

• Layer information

  • Type

  • Width

  • Direction

  • Offset

  • Pitch

• Max stack via

• Viarules

• Sites

• Macro information

  • Size

  • Pins

  • Obstructions

The dictionary returned by this function is designed to mimic the structure of the LEF file as closely as possible, and this function does minimal legality checking. The order all top-level objects appear in the dictionary is guaranteed to match the LEF file. It looks like follows:

{
    'version': 5.8,
    'busbitchars': '<>',
    'dividerchar': ':',
    'units': {
        'capacitance': 10.0,
        'current': 10000.0,
        'database': 20000.0,
        'frequency': 10.0,
        'power': 10000.0,
        'resistance': 10000.0,
        'time': 100.0,
        'voltage': 1000.0
    },
    'manufacturinggrid': 0.05,
    'useminspacing': {'OBS': 'OFF'},
    'clearancemeasure': 'MAXXY',
    'fixedmask': True,
    'layers': {
        'M1': {
            'type': 'ROUTING',
            'direction': 'HORIZONTAL',
            'offset': (0.1, 0.2),
            'pitch': 1.8,
            'width': 1.0
        },
        'V1': {
            'type': 'CUT',
        },
        ...
    },
    'maxviastack': {'range': {'bottom': 'm1', 'top': 'm7'}, 'value': 4},
    'viarules': {
        '<name>': {
            'generate': True,
            'layers': [
                {'enclosure': {'overhang1': 1.4,
                               'overhang2': 1.5},
                 'name': 'M1',
                 'width': {'max': 19.0, 'min': 0.1}},
                {'enclosure': {'overhang1': 1.4,
                               'overhang2': 1.5},
                 'name': 'M2',
                 'width': {'max': 1.9, 'min': 0.2}},
                {'name': 'M3',
                 'rect': (-0.3, -0.3, -0.3, 0.3),
                 'resistance': 0.5,
                 'spacing': {'x': 5.6, 'y': 7.0}}
            ]
        },
        '<name>': {
            {'layers': [
                {'direction': 'VERTICAL',
                 'name': 'M1',
                 'width': {'max': 9.6, 'min': 9.0}},
                 {'direction': 'HORZIONTAL',
                 'name': 'M1',
                 'width': {'max': 3.0, 'min': 3.0}}
            ]}
        },
        ...
    }
    'macros': {
        '<name>': {
            'size': {
                'width': 5,
                'height': 8
            },
            'pins': {
                '<name>': {
                    'ports': [{
                        'class': 'CORE',
                        'layer_geometries': [{
                            'layer': 'M1',
                            'exceptpgnet': True,
                            'spacing': 0.01,
                            'designrulewidth': 0.05,
                            'width': 1.5,
                            'shapes': [
                                {
                                    'rect': (0, 0, 5, 5),
                                    'mask': 1,
                                    'iterate': {
                                        'num_x': 2,
                                        'num_y': 3,
                                        'space_x': 1,
                                        'space_y': 4
                                    }
                                },
                                {
                                    'path': [(0, 0), (5, 0), (0, 5)],
                                    'iterate': ...
                                },
                                {
                                    'polygon': [(0, 0), (5, 0), (0, 5)],
                                    'iterate': ...
                                }
                            ],
                            'via': {
                                'pt': (2, 3),
                                'name': 'via1',
                                'iterate': ...
                            }
                        }]
                    }]
                },
                ...
            }
        },
        ...
    }
}

If some entry is not specified in the LEF, the corresponding key will not be present in the dictionary.

Parameters:

path (str) – Path to LEF file to parse.