# DipTrace Schematic Capture — XML Format Specification

*Generated from the DipTrace serializer, repository revision 7276 — reflects current program behaviour.*

## How to read this specification

This document describes the **DipTrace Schematic Capture** flavour of
the DipTrace XML format — the same format used both for
`File ▸ Save/Open As ▸ DipTrace XML` and for the plug‑in exchange file.
It is generated directly from the DipTrace serializer and reflects what
the program actually reads and writes.

Each element is given with a short description, a representative XML
fragment, and a table of its attributes. The **Written** column states
the condition under which the serializer emits the attribute (`always`,
a guard such as `if >-1`, or a context such as `Text shapes only`); an
attribute left at its default is usually omitted, so a missing attribute
means *use the default*, not zero.

## Document structure

A schematic project is a single `<Source>` root holding the embedded
design‑cache library and the editable schematic:

    <Source Type="DipTrace-Schematic" Version="4.3.0.x" Units="mm">
      <Library Type="DipTrace-ComponentLibrary" ...>...</Library>   <!-- design cache -->
      <Schematic> ... </Schematic>                                  <!-- the editable project -->
    </Source>

The editable schematic data lives under `<Schematic>` (a plug‑in's data
node is `/Source/Schematic`); the sibling `<Library>` is the project's
design cache and nests the footprint (pattern) library.

## Value types & formatting

| Type | Encoding |
|----|----|
| `Int` | A plain decimal integer. |
| `Real` | A decimal number expressed in the file's `Units`, written with a **dot** decimal separator. The reader is tolerant (it normalises both dot and comma), but the dot is canonical and is what other tools expect. |
| `Bool` | `Y` / `N`. (A few Schematic simulator fields use `+` / `-`.) |
| `Text` | A string attribute or element text. |
| `Color` | A 24‑bit integer in Windows `0x00BBGGRR` order (e.g. `255` = red). |
| enum | A fixed set of text (or, in a few cases, integer) values, listed with the element. |

## Coordinate frames, units & angles

- The document root carries `Units="mm" | "inch" | "mil"`. **Every**
  `Real` coordinate, length and size in the file is in those units;
  there is no per‑object override.
- Objects inside a library symbol or footprint (pins, pads, shapes) are
  stored in an **object‑centre** frame — coordinates are relative to the
  part/footprint origin and are not affected by where an instance is
  placed.
- Angles are in **radians, counter‑clockwise**, unless an attribute is
  explicitly a discrete orientation enum (e.g. a footprint `Orientation`
  of `0/90/180/270`).
- Coordinate scaling and sign are internal to the file; read and write
  values as they are — do not rescale or flip them.

## Identifiers, references & list ordering

- Most list elements carry an `Id` (or `Index`/`Number`) that other
  objects reference. A reference value of `-1` means *none / not
  connected*.
- A few lists are referenced **positionally**, not by an `Id` attribute:
  a `ViaStyle` value indexes the in‑order `<ViaStyles>` list and a
  `NetClass` value indexes the in‑order `<NetClasses>` list. Reordering
  those lists silently reassigns the references.
- When a whole file is opened, top‑level object lists are resolved **by
  position**: each array must be dense, ascending from `Id` 0, with
  position equal to `Id`. A file authored out of order or with gaps will
  bind references to the wrong objects.

## Object state flags

| Attribute | Type | Meaning |
|----|----|----|
| `Selected` | Bool | User selection state. |
| `Locked` | Bool | Edit lock. |
| `Group` | Int | Group `Id`, or `-1` for none; groups are listed in a `<Groups>` section. |
| `Enabled` | Bool | *Exists / removed.* A normal save prunes disabled objects, so a saved file rarely shows `Enabled="N"`; on the plug‑in exchange / edit‑import path, however, `Enabled="N"` is honoured as a **delete** flag on the editable objects. An absent flag means enabled. |

## Plug-in exchange & import merge

The same format is the **plug-in exchange** file: DipTrace exports the
selected data, launches the plug-in with the file path as its argument,
waits for it to exit, then re-imports the (possibly edited) file. How
the result merges back depends on the import mode:

- **Whole-list (`ImpMode=All`)** — the incoming list *replaces* the
  project's list of that object kind; anything omitted is removed.
- **`Edit`** — each **top-level** object is matched to an existing one
  **by its `Id`** and overwritten in place; an object with a new or
  absent `Id` is added. Keep an object's `Id` to edit it, and **omit the
  `Id`** on objects you add — never invent one, because over a partial
  export a computed “free” Id can collide with an unexported object and
  overwrite it.

> **Nested lists without their own `Id` are REPLACED, not merged.** A
> net's `<Traces>`, a net's or bus's `<Wires>`, and point lists have no
> per-member `Id`. When such a container is present in your XML,
> DipTrace **discards the existing list and rebuilds it from exactly the
> children you supply** — so appending one trace under an existing net
> replaces that net's *entire* routing. To add one member, re-list every
> current member plus the new one; to leave the list untouched, omit the
> container element entirely.

> **The `Selected` filter skips — it does not add.** When a plug-in runs
> with a `Selected` filter under `Edit`, only objects flagged
> `Selected="Y"` are processed at all: a marked object with an existing
> `Id` is edited, a marked object with a new `Id` is added, and an
> **unflagged** object is **skipped entirely** (neither edited nor
> added). Put `Selected="Y"` on every object you add or edit under such
> a filter, or its data is silently dropped.

To remove an object, set `Enabled="N"` on it and leave it in the file
(see *Object state flags*) — do not delete the XML node. Component and
Pattern *library* files use coarser Library / Component / Part import
modes rather than per-object `Edit`, but the `Enabled` delete flag and
the `Id` rules still apply.

> **A note on completeness.** Where a newer serializer field has no
> counterpart in an older published table (for example the
> real‑valued/mono font fields, or per‑object shield‑group ids), it is
> documented here as a first‑class attribute. Preserve attributes and
> elements you do not recognise when editing a file in place — they
> belong to other subsystems and to future format versions.

## Cross-cutting: font-size fields

Every text-bearing element in the Schematic dialect carries a legacy
rounded integer font size *and* a fractional companion. On import the
fractional value overrides the rounded integer whenever it is present,
so a reader that wants exact sizes must prefer the `…Float` attribute.

| Attribute | Type | Written | Description |
|----|----|----|----|
| `FontSize` / `Font` / `FontSizeFloat` | Int / Real | always (as a pair) | The integer is the rounded legacy size; `FontSizeFloat` holds the true fractional size and wins on import. Written on `<BorderZones>`, `<Field>`, `<Markings>`, `<BusConnections>`, `<PinNumbers>`, `<NetName>`, a text `<Shape>`, `<Table>`, and `<Cell>`. |
| `MarkingFontSize` / `MarkingFontSizeFloat` | Int / Real | always (as a pair) | Same pairing for a `<Part>`'s marking font; the `…Float` twin carries the fractional value. |
| `FontMono` | Bool (Y/N) | vector font only | Written only when the object uses the internal vector font (`FontVector="Y"`); selects the monospaced vector face. Absent for TrueType text. |
| `TextWidth` / `TextHeight` | Real | export-only | Computed bounding size of the text (via `GetTextWH`), emitted for informational use on `<Field>`, text `<Shape>`, and `<Cell>`. Recomputed on import — never read back; treat as read-only. |

> **Note.** The fractional/mono font family is written throughout the
> document but does not replace the integer fields — both are always
> present so older readers keep working. When authoring XML, set the
> `…Float` value; the rounded integer is derived.

## \<SheetSettings\> — page setup and title blocks

Holds the sheet list and per-sheet page geometry, border zones, and up
to six title blocks. Objects across the schematic reference a sheet by
its `Id`.

    <SheetSettings>
      <DisplayTitles>Y</DisplayTitles>
      <DisplaySheet>Y</DisplaySheet>
      <ActiveSheet>0</ActiveSheet>
      <Sheets>
        <Sheet>
          <Id>0</Id> <Name>Sheet1</Name> <Type>Normal</Type>
          <XPos>0</XPos> <YPos>0</YPos> <Scale>1</Scale>
          <SheetWidth>297</SheetWidth> <SheetHeight>210</SheetHeight>
          <LeftMargin>5</LeftMargin> <TopMargin>5</TopMargin>
          <RightMargin>5</RightMargin> <BottomMargin>5</BottomMargin>
          <BorderZones>…</BorderZones>
        </Sheet>
      </Sheets>
    </SheetSettings>

Header children: `DisplayTitles` and `DisplaySheet` (Bool) toggle
title-block / sheet-border display; `ActiveSheet` (Int) is the currently
shown sheet index.

### \<Sheet\>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Sheet index; objects reference it by `Sheet="N"`. |
| `Name` | Text | always | Sheet name. |
| `Type` | enum | always | `0`=Normal, `1`=Hierarchy Block. |
| `BlockId` | Int | if Type is Hierarchy Block | Links this child sheet to the hierarchy-block *part* that expands into it (see the note below); omitted entirely for a normal sheet. |
| `XPos` / `YPos` | Real | always | Sheet origin (Y is negated on write). |
| `Scale` | Real | always | Display scale. |
| `SheetWidth` / `SheetHeight` | Real | always | Page size in file Units. |
| `LeftMargin` / `TopMargin` / `RightMargin` / `BottomMargin` | Real | always | Printable margins. |

> **Hierarchy blocks.** A hierarchical design links a *block part* (a
> `<Part>` of part type 4, carrying a `BlockId`) to the child `<Sheet>`
> that expands it. The link is the matching `BlockId` value written on
> both sides — a content link that is **independent of the positional
> `Sheet Id`** that ordinary objects use through `Sheet="N"`. Do not
> conflate the two: a sheet's `Id` is its page index, its `BlockId` is
> its block identity. If a `BlockId` does not resolve on import,
> DipTrace falls back to matching the block to its sheet by name.

### \<BorderZones\> and the six title blocks

Written only in a full save (not per-object plug-in exports).
`<BorderZones>` carries the zone-grid setup: `Visible`,
`HorzZones`/`VertZones` (Int), `Standard`, `FontName`,
`FontSize`/`FontSizeFloat`, `FontLineWidth` (Real), `Border` (Bool), and
`HorzBorderSize`/`VertBorderSize` (Real). The six title blocks are
separate elements: `<BottomRightBlock>`, `<BottomLeftBlock>`,
`<TopRightBlock>`, `<TopLeftBlock>`, `<ExtTopLeftBlock>`,
`<ExtBottomLeftBlock>`.

    <BottomRightBlock Width="180" Height="55">
      <Name>ANSI A</Name>
      <ColumnWidths><Item>40</Item>…</ColumnWidths>
      <RowHeights><Item>10</Item>…</RowHeights>
      <Cells><Item><Item FieldId="0" TopLine="Y" BottomLine="Y" LeftLine="Y" RightLine="Y"/>…</Item></Cells>
      <Fields>
        <Field Id="0" FontVector="N" FontSize="10" FontSizeFloat="10" FontWidth="-2"
               FontScale="1" FontColor="0" LineSpacing="1.2" TextShow="Text" TextAlign="Left"
               X1="0" Y1="0" X2="40" Y2="10" TextWidth="18" TextHeight="4">
          <TextLines><TextLine>Title</TextLine></TextLines>
          <FontName>Tahoma</FontName>
        </Field>
      </Fields>
    </BottomRightBlock>

> **Note.** A title block is omitted when its `Name` is blank, and
> `ColumnWidths`/`RowHeights`/`Cells`/`Fields` are omitted when empty —
> all optional. A `<Field>` emits `FontMono` only when `FontVector="Y"`,
> and `TextWidth`/`TextHeight` only for a plain text field
> (`TextShow="Text"`).

## \<Settings\> — global project settings

Global fonts, grid, origin, line widths, bus-connection display, pin
numbers, and the net-label font. Emitted as a block of child elements.

    <Settings>
      <Markings FontVector="Y" FontMono="N" FontSize="10" FontSizeFloat="10"
                FontWidth="-2" FontScale="1" UsePartFontColor="N" FontColor="0">
        <RefDesGlobal Show="Common" ShowPart="Common" Align="Auto"/>
        <NameGlobal …/> <ValueGlobal …/> <ManufacturerGlobal …/> <DatasheetGlobal …/>
      </Markings>
      <Grid Visible="Y" Snap="Y" Size="2.5"/>
      <Origin Visible="N" AxisColor="0" X="0" Y="0"/>
      <LineWidth Wire="0.25" NodeSize="1" Bus="0.5" Table="0.25" Titles="0.25"/>
      <BusConnections Show="NetName" Position="Above" FontSize="8" FontSizeFloat="8"/>
      <PinNumbers Visible="Y" Font="8" FontSizeFloat="8"/>
      <NetName FontSize="8" FontSizeFloat="8"/>
      <HidePower>N</HidePower>
      <ProjectDir>…</ProjectDir>
    </Settings>

`<Markings>` holds the shared component-marking font (`FontVector`,
`FontMono` in the vector branch, `FontName` in the TrueType branch, plus
`FontSize`/`FontSizeFloat`/`FontWidth`/`FontScale`/`UsePartFontColor`/`FontColor`)
and per-field show/align children `<RefDesGlobal>`, `<NameGlobal>`,
`<ValueGlobal>`, `<ManufacturerGlobal>`, `<DatasheetGlobal>`, and an
optional `<AddFieldsGlobal>` list.

| Element / Attr | Type | Written | Description |
|----|----|----|----|
| `<Grid>` `Visible`/`Snap`/`Size` | Bool/Bool/Real | always | Grid display, snapping, spacing. |
| `<Origin>` `X`/`Y`/`Visible`/`AxisColor` | Real/Real/Bool/Int | always | User origin position, visibility, axis color. |
| `<LineWidth>` `Wire`/`NodeSize`/`Bus`/`Table`/`Titles` | Real | always | Default widths for wires, junction node size, buses, table lines, title lines. |
| `<BusConnections>` `Show`/`Position`/`FontSize`/`FontSizeFloat` | enum/enum/Int/Real | always | `Show`: NetName/Number; `Position`: Above/Below; the label font size. |
| `<PinNumbers>` `Visible`/`Font`/`FontSizeFloat` | Bool/Int/Real | always | Pin-number display and font size. |
| `<NetName>` `FontSize`/`FontSizeFloat` | Int/Real | always | Net-label font size (schematic net names), between `<PinNumbers>` and `<HidePower>`. |
| `<HidePower>` | Bool | always | Hide power/ground pins. |
| `<ProjectDir>` | Text | always | Project directory. |

## \<NetClasses\> / \<NetClass\>

The project's net classes, written in order. The diff-pair rule
attributes appear only for a Differential Pair class.

    <NetClasses>
      <NetClass Id="0" UpdateId="0" Type="Normal" Width="0.25" Clearance="0.25">
        <Name>Default</Name>
      </NetClass>
      <NetClass Id="1" UpdateId="3" Type="Differential Pair" Width="0.2" Clearance="0.2"
                DifClearance="0.2" MaxUncoupledLength="5" Tolerance="0.1" Phase="0" Phase_ErrorLength="0">
        <Name>DiffPair</Name>
      </NetClass>
    </NetClasses>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | In-order index of the class (equals its list position). |
| `UpdateId` | Int | always | Cross-link id for update against the PCB. |
| `Type` | enum | always | `0`=Normal, `1`=Differential Pair. |
| `Width` | Real | if \>-1 | Default trace width. |
| `Clearance` | Real | if \>-1 | Default clearance. |
| `DifClearance` | Real | Diff Pair, if \>-1 | In-pair clearance. |
| `MaxUncoupledLength` | Real | Diff Pair only | Max uncoupled length. |
| `Tolerance` | Real | Diff Pair only | Length-match tolerance. |
| `Phase` | Real | Diff Pair only | Phase-match target. |
| `Phase_ErrorLength` | Real | Diff Pair only | Phase error length. |
| `<Name>` | Text | always | Class name (child element). |

> **Note.** A net selects its class with `NetClass="N"`, a **positional
> index** into this in-order list. On a native save `Id` equals that
> position, so the two agree; reordering `<NetClass>` entries silently
> reassigns classes.

## \<DesignCache\>

Records how many leading components in the embedded `<Library>` are
design-cache entries.

    <DesignCache Count="3"/>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Count` | Int | always | Number of leading design-cache components (stored as the internal cache count plus one). |

## \<ERC\>

Electrical-rules-check flags and the power/ground name templates.

    <ERC CheckPinType="Y" CheckNotConnected="Y" CheckSinglePin="Y" CheckShort="Y" CheckPinSuperimpose="Y">
      <VCCTemplate>VCC;+*</VCCTemplate>
      <GNDTemplate>GND;0</GNDTemplate>
    </ERC>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `CheckPinType` | Bool | always | Check pin-type conflicts. |
| `CheckNotConnected` | Bool | always | Check not-connected pins. |
| `CheckSinglePin` | Bool | always | Check single-pin nets. |
| `CheckShort` | Bool | always | Check shorts. |
| `CheckPinSuperimpose` | Bool | always | Check superimposed pins. |
| `<VCCTemplate>` / `<GNDTemplate>` | Text | always | Power / ground net-name templates (child elements). |

## \<Components\> / \<Part\>

One `<Part>` per placed part/section; several parts of a multi-part
component share a `RefDes`. `ComponentStyle` points to a symbol in the
embedded library and `ComponentPart` selects the section within it.

    <Part Id="0" UpdateId="2221" ComponentStyle="CompType229" ComponentPart="0" AllowParts="N"
          PartNumber="1" Sheet="4" X="83.82" Y="-43.815" Angle="4.7124"
          MarkingFontSize="10" MarkingFontSizeFloat="10">
      <RefDes>C1</RefDes> <PartRefDes>1</PartRefDes> <PartName>Part 1</PartName>
      <Value>(1608)</Value> <Name>CAP_1608(0603)</Name> <BaseName>CAP</BaseName>
      <Manufacturer>Yageo</Manufacturer> <Datasheet>http://…</Datasheet>
      <LibPath><Path>…</Path><Var>…</Var></LibPath>
      <RefDesMarking Show="Common" Align="Auto" Horz="Left" Vert="Top" X="0" Y="0" Angle="0"/>
      <NameMarking …/> <ValueMarking …/> <ManufacturerMarking …/> <DatasheetMarking …/>
      <Pins><Pin NetId="0"/><Pin NetId="-1" NotConnected="Y"/></Pins>
    </Part>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Part id; net pin items reference it. |
| `UpdateId` | Int | always | Cross-link id to the PCB component. |
| `BlockId` | Int | hierarchy-block part only | Hierarchy-block link (part type 4); matches the `BlockId` of the child `<Sheet>` it expands into. |
| `ComponentStyle` | Text | if library entry resolved | Symbol name in the embedded library. |
| `ComponentPart` | Int | always | Section index within that symbol. |
| `AllowParts` | Bool | always | Whether the component is split into parts/sections. |
| `PartNumber` | Int | always | This part's number within the component. |
| `Sheet` | Int | always | Owning sheet `Id`. |
| `X` / `Y` | Real | always | Placement (Y negated on write). |
| `Angle` | Real | if ≠0 | Rotation, radians CCW. |
| `HorzFlip` / `VertFlip` | Bool | if flipped | Mirror flags (only `Y` is written). |
| `ShowNumbers` | enum | if \>0 | `0`=Common, `1`=Show, `2`=Hide. |
| `ShowOrigin` | Bool | if set | Show the part origin. |
| `CustomMarkingFont` | Bool | if set | Part overrides the global marking font. |
| `MarkingFontSize` / `MarkingFontSizeFloat` | Int / Real | always | Marking font size (float twin wins on import). |
| `MarkingFontAll` | Bool | if set | Apply the marking font to all fields. |
| `Group` | Int | if \>-1 | Group id, else omitted. |
| `Selected` / `Locked` | Bool | if set | Editor flags (only `Y` written). |

Value elements (child text, all always written): `<RefDes>`,
`<PartRefDes>`, `<PartName>`, `<Value>`, `<Name>`, `<BaseName>` (the
component base name), `<Manufacturer>` (the manufacturer value, distinct
from the display-only `<ManufacturerMarking>`), and `<Datasheet>` (the
datasheet value, distinct from `<DatasheetMarking>`). Followed by
`<LibPath>`, the five marking-display blocks (`<RefDesMarking>` …
`<DatasheetMarking>`, each with
`Show`/`ShowPart`/`Align`/`Horz`/`Vert`/`X`/`Y`/`Angle`), an optional
`<AddFields>` list, the `<Pins>` list, and an optional `<Category>`.

### \<Pins\> (of a Part)

The part's pins in symbol pin order; nets reference a pin by this
positional index.

| Attribute | Type | Written | Description |
|----|----|----|----|
| `NetId` | Int | always | Connected net `Id`, or `-1` for none. |
| `NotConnected` | Bool | if set | Explicitly marked not-connected (only `Y` written). |

> **Note.** A normal save never writes `Enabled` on a `<Part>` —
> disabled parts are pruned. Since rev 7272 the plug-in importer honors
> `Enabled="N"` on a `<Part>` as a delete flag (see the closing note
> under `<Groups>`).

## \<Nets\> / \<Net\>

Each net lists its pin memberships and its wires. Boolean flags are
written only when set (as `Y`), except `Enabled`, which is written as
`N` for a deleted net.

    <Net Id="0" NetClass="0" HiddenId="0" Global="Y" CustomColor="Y" WireColor="255">
      <Name>AP-WAKE-BT</Name>
      <Pins><Item Part="596" Pin="0"/><Item Part="347" Pin="2"/></Pins>
      <Wires>
        <Wire Id="0" Sheet="1" Connected1="Pin" Bus1="-1" Object1="709" SubObject1="0"
              Connected2="Wire" Bus2="-1" Object2="3" SubObject2="1"
              HiddenPower="N" CanUnhide="N">
          <Points><Point X="-1.27" Y="-13.97" Dir="-1"/><Point X="0" Y="-13.97" Dir="0"/></Points>
        </Wire>
      </Wires>
    </Net>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Net id; referenced by pins, shapes, buses, diff pairs. |
| `NetClass` | Int | always | Positional index into `<NetClasses>`. |
| `HiddenId` | Int | always | Internal stable id used across merge/update. |
| `UniteByName` | Bool | if set | Unite same-named nets. |
| `ConnectPinByName` | Bool | if set | Connect pins by name. |
| `Global` | Bool | if set | Global net. |
| `CustomColor` | Bool | if set | Use a custom wire color; when set, `WireColor` follows. |
| `WireColor` | Int | if custom & ≠0 | Custom wire color. |
| `Locked` | Bool | if set | Locked. |
| `Enabled` | Bool | `N` only, for a deleted net | The one object that genuinely emits `Enabled="N"` (delete flag). Never written when enabled. |
| `<Name>` | Text | always | Net name (child element). |

`<Pins>` holds `<Item Part="…" Pin="…"/>` — the part `Id` plus the pin's
positional index in that part.

### \<Wire\> / \<Point\>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Wire id within the net. |
| `Sheet` | Int | always | Owning sheet. |
| `Connected1` / `Connected2` | enum | always | Endpoint kind — see enum below. |
| `Bus1` / `Bus2` | Int | always | Connected bus `Id` when the endpoint is a bus, else `-1`. |
| `Object1` / `Object2` | Int | always | Endpoint target: Pin→part `Id`; Wire→another wire `Id` in the net; Bus→bus-wire `Id`. |
| `SubObject1` / `SubObject2` | Int | always | Pin→pin index in the part; Wire/Bus→point index in that wire. |
| `HiddenPower` | Bool | always | Hidden power/ground wire. |
| `CanUnhide` | Bool | always | Whether a hidden wire may be unhidden. |
| `Arrows` | enum | if \>0 | `0`=None, `1`=Forward, `2`=Backward. |
| `Group` | Int | if \>-1 | Group id. |
| `Selected` | Bool | if set | Editor flag. |

| Value | Name                         |
|-------|------------------------------|
| `0`   | Pin                          |
| `1`   | Wire                         |
| `2`   | 2 (net-junction placeholder) |
| `3`   | Bus                          |
| `4`   | Free                         |

Each `<Point>` carries `X`/`Y` (Real, Y negated) and `Dir` (Int): `-1`
unset, `0` horizontal, `1` vertical — the direction is stored on the
segment's second point; the first point's `Dir` is ignored.

## \<DifferentialPairs\> / \<DifferentialPair\>

Pairs the positive and negative nets of a differential pair.

    <DifferentialPairs>
      <DifferentialPair Id="0" PosNet="4" NegNet="5" NetClass="1" CustomColor="Y" WireColor="16711680">
        <Name>USB_D</Name>
      </DifferentialPair>
    </DifferentialPairs>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Pair index (load-bearing on merge/exchange import). |
| `PosNet` / `NegNet` | Int | always | Positive / negative net `Id`. |
| `NetClass` | Int | always | Positional net-class index. |
| `CustomColor` | Bool | if set | Use a custom color; when set, `WireColor` follows. |
| `WireColor` | Int | if custom | Custom wire color. |
| `<Name>` | Text | always | Pair name (child element). |

> **Note.** `Enabled` is not produced for a diff pair — the export loop
> is gated on the enabled flag, so a disabled pair is pruned (no
> element). The presence of the element itself is the "enabled" signal.
> The reader still accepts `Enabled` on hand-authored XML.

## \<Buses\> / \<Bus\> and \<BusConnectors\> / \<BusConnector\>

A bus lists its member nets and its bus wires. Bus connectors are the
named ports that join a bus to nets.

    <Buses>
      <Bus Id="0">
        <Name>DATA</Name>
        <Nets><Net NetId="4" ConnectionNumber="0"/><Net NetId="5" ConnectionNumber="1"/></Nets>
        <Wires>
          <Wire Id="0" Sheet="1" Connected1="Bus Connector" Bus1="-1" Object1="2" SubObject1="0"
                Connected2="Bus Wire" Bus2="-1" Object2="1" SubObject2="0">
            <Points><Point X="10" Y="-20" Dir="-1"/>…</Points>
          </Wire>
        </Wires>
      </Bus>
    </Buses>
    <BusConnectors>
      <BusConnector Id="0" Sheet="1" X="10" Y="-20" Connected="Y"><Name>DATA</Name></BusConnector>
    </BusConnectors>

### \<Bus\>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Bus id. |
| `Locked` | Bool | if set | Locked. |
| `Enabled` | Bool | — | Not emitted by a native save (loop gated on enabled). Reader-accepted delete flag. |
| `<Name>` | Text | always | Bus name (child element). |

`<Nets>` holds `<Net NetId="…" ConnectionNumber="…"/>` (member net `Id`
and its ordinal in the bus). `<Wires>` holds bus `<Wire>`s with the same
connection model as net wires (`Id`, `Sheet`, `Connected1/2`, `Bus1/2`,
`Object1/2`, `SubObject1/2`, optional `Group`/`Selected`) and
`<Points>`. Bus-wire endpoint kinds: `2`=Bus Wire, `4`=Bus Connector,
all other values render as Free.

### \<BusConnector\>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Connector id. |
| `Sheet` | Int | always | Owning sheet. |
| `X` / `Y` | Real | always | Position (Y negated). |
| `Connected` | Bool | always | Whether the connector is attached to a bus. |
| `Enabled` | Bool | — | Not emitted by a native save (loop gated on enabled). Reader-accepted delete flag. |
| `Group` | Int | if \>-1 | Group id. |
| `Selected` / `Locked` | Bool | if set | Editor flags. |
| `<Name>` | Text | always | Port name (child element). |

## \<Shapes\> / \<Shape\>

Free graphics and text. Attribute set varies by `Type`: line-style
attributes for outlines/fills, picture attributes for pictures, and the
full font family for text.

    <Shape Id="0" Type="Rectangle" Sheet="0" LineWidth="0.25" Color="9079434" Selected="N">
      <Points><Point X="86.995" Y="21.59"/><Point X="120" Y="40"/></Points>
    </Shape>
    <Shape Id="1" Type="Text" Sheet="0" Angle="0" HorzAlign="Left" VertAlign="Top" TextAlign="Left"
           FontVector="Y" FontMono="N" FontSize="10" FontSizeFloat="10" FontWidth="-2" FontScale="1"
           FontColor="0" LineSpacing="1.2" TextWidth="18" TextHeight="4">
      <Points><Point X="10" Y="-5"/></Points>
      <FontName>Tahoma</FontName>
      <TextLines><TextLine>Power</TextLine></TextLines>
    </Shape>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Shape index. |
| `Type` | enum | always | See enum below. |
| `Sheet` | Int | always | Owning sheet. |
| `LineWidth` | Real | all types except Text and Picture, if \>-1 | Outline width — written for fills too (FillRect, FillObround). |
| `Color` | Int | all types except Text and Picture | Line/fill color. |
| `NetId` | Int | Text shapes, if ≥0 | Bound net (net-name label). |
| `BusId` | Int | Text shapes, if ≥0 | Bound bus (bus label). |
| `Angle` | Real | Text and Picture | Text/picture rotation. |
| `PictureWidth` / `PictureHeight` | Real | Picture only | Picture size. |
| `PictureProportions` | Bool | Picture only | Keep aspect ratio. |
| `PictureFlipped` | Bool | Picture only | Picture mirrored. |
| `PictureTransparent` | Int | Picture only | Transparent-color value. |
| `HorzAlign` / `VertAlign` | enum | Text and Picture | Anchor alignment (Left/Center/Right; Top/Center/Bottom). |
| `TextAlign` | enum | Text only | Paragraph alignment. |
| `FontVector` | Bool | Text only | Vector vs TrueType font; `FontMono` follows when `Y`. |
| `FontSize` / `FontSizeFloat` | Int / Real | Text only | Font size (float twin wins on import). |
| `FontWidth` / `FontScale` / `FontColor` / `LineSpacing` | Real/Real/Int/Real | Text only | Stroke width, scale, color, line spacing. |
| `TextWidth` / `TextHeight` | Real | Text only, if has lines | Computed text extent (informational). |
| `Group` | Int | if \>-1 | Group id. |
| `Selected` / `Locked` | Bool | if set | Editor flags. |

| Value | Name        |
|-------|-------------|
| `0`   | None        |
| `1`   | Line        |
| `2`   | Arc         |
| `3`   | Arrow       |
| `4`   | Rectangle   |
| `5`   | FillRect    |
| `6`   | Obround     |
| `7`   | FillObround |
| `8`   | Polyline    |
| `9`   | Polygon     |
| `10`  | Text        |
| `11`  | Picture     |

Child elements: `<Points>`/`<Point X Y>` (geometry). A Text shape also
writes `<FontName>` and a `<TextLines>`/`<TextLine>` list; a Picture
shape writes a `<PictureFile>` (`<Path>`/`<Var>`).

> **Note.** `LineWidth` and `Color` are written for filled shapes
> (FillRect, FillObround) too — the only exclusions are Text and
> Picture. `Enabled` is not emitted (disabled shapes are pruned); the
> reader accepts it as a delete flag.

## \<Tables\> / \<Table\> / \<Cell\>

Free / BOM tables. Table-level attributes carry the default cell font;
each cell can override it.

    <Table Id="0" Sheet="1" X1="10" Y1="-10" X2="90" Y2="-40" Orientation="0"
           CellWidth="20" CellHeight="6" TextAlign="Left" FontVector="Y" FontMono="N"
           FontSize="8" FontSizeFloat="8" FontWidth="-2" FontScale="1" FontColor="0" LineSpacing="1.2">
      <FontName>Tahoma</FontName> <Name>BOM</Name>
      <ColWidths><Item>20</Item>…</ColWidths>
      <RowHeights><Item>6</Item>…</RowHeights>
      <Cells>
        <Cell>
          <Cell X1="10" Y1="-10" X2="30" Y2="-16" TextAlign="Left" FontVector="Y" FontMono="N"
                FontSize="8" FontSizeFloat="8" FontWidth="-2" FontScale="1" FontColor="0"
                LineSpacing="1.2" TextWidth="12" TextHeight="4">
            <FontName>Tahoma</FontName>
            <TextLines><TextLine>RefDes</TextLine></TextLines>
          </Cell>
        </Cell>
      </Cells>
    </Table>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Table index. |
| `Sheet` | Int | always | Owning sheet. |
| `HideBorder` | Bool | if set | Suppress the outer border. |
| `X1`/`Y1`/`X2`/`Y2` | Real | always | Table rectangle (Y negated). |
| `Orientation` | enum | always | `0`/`1`/`2`/`3` = 0/90/180/270. |
| `CellWidth` / `CellHeight` | Real | always | Default cell size. |
| `TextAlign` | enum | always | Default cell alignment (Left/Center/Right). |
| `FontVector` / `FontMono` | Bool | always / vector only | Default cell font kind; `FontMono` only when vector. |
| `FontSize` / `FontSizeFloat` | Int / Real | always | Default cell font size. |
| `FontWidth` / `FontScale` / `FontColor` / `LineSpacing` | Real/Real/Int/Real | always | Default cell font metrics. |
| `Group` | Int | if \>-1 | Group id. |
| `Selected` / `Locked` | Bool | if set | Editor flags. |
| `<FontName>` / `<Name>` | Text | always | Default font family; table name. |

Cells are written as a `<Cells>` list of rows, each row a `<Cell>`
containing the row's `<Cell>` entries. A cell carries its own rectangle
(`X1`/`Y1`/`X2`/`Y2`), `TextAlign`, the full font family (`FontVector`,
`FontMono` when vector,
`FontSize`/`FontSizeFloat`/`FontWidth`/`FontScale`/`FontColor`/`LineSpacing`,
`<FontName>`), and, when it has text, `TextWidth`/`TextHeight` plus a
`<TextLines>`/`<TextLine>` list.

> **Note.** The row and cell wrappers share the tag name `<Cell>` — the
> outer level is a row, the inner level a cell. `Enabled` is not emitted
> (disabled tables are pruned); the reader accepts it as a delete flag.

## \<Simulator\> — SPICE setup

Written only when the project has simulation data. Carries the analysis
type, plotted signals, per-analysis parameter blocks, a
digital-simulation block, and four SPICE solver-options blocks.

    <Simulator Type="Transient" GndNetId="0">
      <Signals>
        <Signal Type="Voltage" Id="4" Plotted="Y" Visible="Y" Color="255">
          <DisplayName>V(out)</DisplayName>
        </Signal>
      </Signals>
      <Transient><StartTime>0</StartTime><Step>1u</Step><StopTime>1m</StopTime></Transient>
      <Digital><StartTime>0</StartTime><Step>1n</Step><StopTime>1u</StopTime><GroupBuses>Y</GroupBuses></Digital>
      <OptionsGeneral NoPrintStat="N" NoPrintModelParams="N"><Temp>27</Temp><TempNomMeasure>27</TempNomMeasure></OptionsGeneral>
      <OptionsDC ConductanceSteps="0" SkipConductanceStepping="N" Iteration="100" TransferCurveIteration="50" StartFromConductanceStepping="N">…</OptionsDC>
      <OptionsAC NoOPAnalysis="N"/>
      <OptionsTransient LowIteration="0" PointIteration="10" TotalIteration="5000" SourceStepping="0" MethodMaxOrder="2" Method="1">…</OptionsTransient>
      <GndNetName>GND</GndNetName>
    </Simulator>

| Attribute  | Type | Written | Description                      |
|------------|------|---------|----------------------------------|
| `Type`     | enum | always  | Analysis type — see enum below.  |
| `GndNetId` | Int  | always  | Ground net `Id` (`-1` for none). |

| Value | Name                 |
|-------|----------------------|
| `1`   | Small-Signal AC      |
| `2`   | DC Transfer Function |
| `4`   | Noise                |
| `9`   | Transient            |
| `10`  | Digital              |
| `11`  | Options              |

Child blocks (each written when it has data): `<Signals>` of
`<Signal Type Id Plotted Visible Color>` with a `<DisplayName>` (`Type`:
`0`=Current, `1`=Voltage); `<SmallSignalAC>`, `<DCTransferFunc>`,
`<Transient>`, `<Noise>` parameter blocks; and `<Digital>`
(`<StartTime>`/`<Step>`/`<StopTime>`/`<GroupBuses>`).

### SPICE solver-options blocks

Four blocks written unconditionally within `<Simulator>`, carrying the
numeric SPICE options as text/attribute values.

- `<OptionsGeneral>`: `NoPrintStat`, `NoPrintModelParams` (Bool attrs);
  `<Temp>`, `<TempNomMeasure>` (text).
- `<OptionsDC>`: attrs `ConductanceSteps`, `SkipConductanceStepping`,
  `Iteration`, `TransferCurveIteration`, `StartFromConductanceStepping`;
  text children `<AbsCurrentTolerance>`, `<MinConductance>`,
  `<PivotRation>`, `<PivotTolerance>`, `<RelativeError>`,
  `<GroundResistor>`, `<VoltageError>`.
- `<OptionsAC>`: `NoOPAnalysis` (Bool attr).
- `<OptionsTransient>`: attrs `LowIteration`, `PointIteration`,
  `TotalIteration`, `SourceStepping`, `MethodMaxOrder`, `Method`
  (`0`=unknown, `1`=default/Trapezoidal, `2`=Gear); text children
  `<ChargeTolerance>`, `<SourceSteppingChange>`, `<ErrorTolerance>`,
  `<TrapezoidalDampingFactor>`.

The block closes with a `<GndNetName>` text element.

## \<Groups\> / \<Group\>

Registry of object groups.

    <Groups>
      <Group Id="0" Selected="N"/>
      <Group Id="1" Enabled="N"/>
    </Groups>

| Attribute | Type | Written | Description |
|----|----|----|----|
| `Id` | Int | always | Group id; objects reference it via `Group`. |
| `Enabled` | Bool | `N` only, for a deleted group | Written as `N` when the group is removed; otherwise omitted. |
| `Selected` | Bool | if set | Editor flag (only `Y` written). |

> **Note. `Enabled` across the dialect.** `Enabled="N"` is the
> import/exchange **delete flag**, honored by the plug-in importer for
> nets, shapes, tables, buses, bus connectors, differential pairs,
> groups, *and* parts. On a native save it is genuinely emitted only for
> a deleted `<Net>` and a deleted `<Group>`; for shapes, tables, buses,
> bus connectors, diff pairs, and parts the disabled object is simply
> pruned (no element), so a written `Enabled="N"` comes only from
> hand-authored or plug-in XML. **Wires carry no `Enabled` at all** —
> remove a wire by dropping it from its net's `<Wires>` list (the list
> is subtree-replaced when present), or remove the whole net with its
> wires via `Enabled="N"` on the `<Net>`.