symbol module

Schematic Symbols

This module provides classes for defining schematic symbols, pins, and symbol mappings for components. You attach a symbol to a component by assigning it to a member field. The name of the field is not important, and multiple symbols can be attached to the same component to provide multiple symbol units.

class Symbol

Bases: Structural

Symbols are a structural element in JITX encoding the schematic representation of a part. Symbols often contain electrical connection points represented by Pin, geometric artwork, and Text annotations. Symbols are linked to a design through a Component where a symbol’s Pin objects are mapped to Port objects.

Valid elements in a symbol are:

• Shape

• Pin

• SymbolOrientation

• Symbol

If a symbol is defined inside another symbol, they will be treated together as one symbol in the design.

For a rectangular symbol with automatic or configurable pin layout, use BoxSymbol.

>>> class MySymbol(Symbol):
...     a = Pin(at=(1, 0), length=1, direction=Direction.Right)
...     b = Pin(at=(-1, 0), length=1, direction=Direction.Left)
...     pin_name_size = 0.3
...     pad_name_size = 0.3
...     orientation = SymbolOrientation(0)
...     rect = rectangle(2, 2)

>>> class MyComponent(Component):
...     ports = [Port() for _ in range(2)]
...     symbol = BoxSymbol()

Note

Grid units are abstract schematic units where 1 grid unit equals the standard pin spacing in the schematic editor.

pin_name_size: float | None = None

Font size of pin name text of Pin objects in this symbol, in grid units. If unset, defers to a parent Symbol, if a parent exists. This can be overriden at the Pin level by setting its pin_name_size attribute.

pad_name_size: float | None = None

Font size of pad name text of Pin objects in this symbol, in grid units. If unset, defers to a parent Symbol, if a parent exists. This can be overriden at the Pin level by setting its pad_name_size attribute.

class Direction(*values)

Bases: Enum

Pin direction on schematic symbols.

Left = 'left'

Right = 'right'

Up = 'up'

Down = 'down'

class Pin(at, length=0, direction=Direction.Left, pin_name_size=None, pad_name_size=None)

Bases: Structural

Schematic symbol pin definition.

Parameters:

• at (GridPoint)

• length (int)

• direction (Direction)

• pin_name_size (float | None)

• pad_name_size (float | None)

at: GridPoint

The position of the pin in grid units.

length: int = 0

The length of the pin in grid units.

direction: Direction = 'left'

The direction of the pin.

pin_name_size: float | None = None

Font size of the pin’s pin name text in grid units, overriding the parent Symbol’s pin_name_size attribute.

pad_name_size: float | None = None

Font size of the pin’s pad name text in grid units, overriding the parent Symbol’s pad_name_size attribute.

classmethod left(at, length=0, pin_name_size=None, pad_name_size=None)

Create a left-facing pin (wire extends to the left).

Parameters:

• at (TypeAliasType) – Grid position (row, column) for the pin.

• length (int) – Length of the pin wire in grid units.

• pin_name_size (float | None) – Optional font size for pin name label.

• pad_name_size (float | None) – Optional font size for pad name label.

Returns:

A Pin instance configured to face left.

>>> Pin.left((0, 0), length=2)  # Pin at row 0, col 0

classmethod right(at, length=0, pin_name_size=None, pad_name_size=None)

Create a right-facing pin (wire extends to the right).

Parameters:

• at (TypeAliasType) – Grid position (row, column) for the pin.

• length (int) – Length of the pin wire in grid units.

• pin_name_size (float | None) – Optional font size for pin name label.

• pad_name_size (float | None) – Optional font size for pad name label.

Returns:

A Pin instance configured to face right.

>>> Pin.right((0, 5), length=2)  # Pin at row 0, col 5

classmethod up(at, length=0, pin_name_size=None, pad_name_size=None)

Create an up-facing pin (wire extends upward).

Parameters:

• at (TypeAliasType) – Grid position (row, column) for the pin.

• length (int) – Length of the pin wire in grid units.

• pin_name_size (float | None) – Optional font size for pin name label.

• pad_name_size (float | None) – Optional font size for pad name label.

Returns:

A Pin instance configured to face up.

>>> Pin.up((5, 2), length=1)  # Pin at row 5, col 2

classmethod down(at, length=0, pin_name_size=None, pad_name_size=None)

Create a down-facing pin (wire extends downward).

Parameters:

• at (TypeAliasType) – Grid position (row, column) for the pin.

• length (int) – Length of the pin wire in grid units.

• pin_name_size (float | None) – Optional font size for pin name label.

• pad_name_size (float | None) – Optional font size for pad name label.

Returns:

A Pin instance configured to face down.

>>> Pin.down((0, 2), length=1)  # Pin at row 0, col 2

class SymbolMapping(entries)

Bases: Structural, Ref

Mapping between component ports and schematic symbol pins.

If no symbol mapping is provided, a default mapping will be created that maps ports to symbol pins in declaration order.

>>> class MyComponent(Component):
...     GND = Power()
...     VIN = Power()
...     VOUT = Power()
...
...     symbol = MySymbol()
...     mappings = SymbolMapping({
...         GND: symbol.gnd,
...         VIN: symbol.vin,
...         VOUT: symbol.vout,
...     })

Parameters:

entries (Mapping[Port, Pin] | Iterable[tuple[Port, Pin]])

items()

values()

class SymbolOrientation(rotations=())

Bases: object

Permitted orientations for a schematic symbol.

In initial placement of schematic symbols, the engine may rotate the symbol to be in any of the permitted orientations. If no orientations are specified, then all orientations are permitted.

Parameters:

rotations (list[int])

rotations: list[int]

List of allowed rotation angles in degrees.