Eeschema Chapter6 JA
Hierarchical schematics
はじめに
シート数が２～３枚で済まないようなプロジェクトには、階層的表現を用いるのが一般的によい解決策となります。この種のプロジェクトを管理したい場合、次のことが必要になります：
- 大きなサイズのシートを使用する。その場合、印刷と取り扱いの問題が生じます。
- シートを数枚使用する。これは階層構造に至ります。
この時、完全な回路図は、ルートシートというメインの回路図シートおよび階層を構成するサブシートというものになります。さらに、設計を個別のシートにうまく分割すると可読性が改善されます。
ルートシートからすべてのサブシートを辿ることができなければなりません。Eeschemaには、右上のツールバーのアイコン[[Image:]]で使用可能な統合"階層ナビゲーター"があり、階層回路図の管理が非常に簡単です。
階層は２種類あり、これらは共存在可能です： １つ目は、すでに開いていて普通に使用するものです。２つ目は、回路図上の従来のコンポーネントのような外観をしたコンポーネントをライブラリ内で作成するというものですが、それは実際にはコンポーネントの内部構造を記述した回路図に対応します。
この２つ目のタイプは集積回路を開発するために使用します。それは、作成中の回路図で機能ライブラリを使用しなければならないからです。
Eeschemaは現在この第２のケースには対応していません。
階層は次のようなもです：
- 単一： 任意のシートを一度だけ使用する
- 複合： 任意のシートを２回以上使用する(複数の実体)
- 平(Flat)： 単一の階層であるが、シート間の接続は記述されない。
Eeschemaはこれら全ての階層を扱うことが可能です。
階層回路図の作成は簡単です。階層全体はルート回路図から始まるように管理され、ただ一つの回路図しかないように見えます。
次の２つの重要なステップを理解する必要があります：
- サブシートの作成方法。
- サブシート間の電気的な接続方法。
階層内のナビゲーション
水平ツールバー上の[[Image:]]ボタンでナビゲーターツールが使用可能になり、それによりサブシート間のナビゲーションは非常に簡単です。
[[Image:]]
シート名をクリックするとそのシートに移動可能になります。すばやく移動するには、シート名を右クリックし、シートに入るを選択します.
右垂直ツールバーの[[Image:]]ツールにより、ルートシートあるいはサブシートに素早く移動可能です。ナビゲーションツールを選択後に以下の操作を行います：
- シート名をクリックしてそのシートに移動する。
- それ以外の場所をクリックしてメインシートに移動する。
Local, hierarchical and global labels
Properties
Local labels, tool [[Image:]], are connecting signals only within a sheet. Hierarchical labels (tool [[Image:]]) are connecting signals only within a sheet and to a hierarchical pin placed in the parent sheet.
Global labels (tool [[Image:]]) are connecting signals across all the hierarchy. Power pins (type power in and power out) invisible are like global labels because they are seen as connected between them across all the hierarchy.
Notes
Within a hierarchy (simple or complex) one can use both hierarchical labels and/or global labels.
Hierarchy creation of headlines
You have to:
- Place in the root sheet a hierarchy symbol called ｡ﾈsheet symbol｡ﾉ.
- Enter into the new schematic (sub-sheet) with the navigator and draw it, like any other schematic.
- Draw the electric connections between the two schematics by placing Global Labels (HLabels) in the new schematic (sub-sheet), and labels having the same name in the root sheet, known as SheetLabels. These SheetLabels will be connected to the sheet symbol of the root sheet to the other elements of the schematic like standard component pins.
Sheet symbol
Draw a rectangle defined by two diagonal points symbolizing the sub-sheet.
The size of this rectangle must allow you to place later particular labels, hierarchy pins, corresponding to the global labels (HLabels) in the sub-sheet .
These labels are similar to usual component pins. Select the tool [[Image:]].
Click to place the upper left corner of the rectangle. Click again to place the lower right corner, having a large enough rectangle.
Example :
[[Image:]]
You will then be prompted to type a file name and a sheet name for this sub-sheet (in order to reach the corresponding schematic, using the hierarchy navigator).
[[Image:]]
You must give at least a file name. If there is no sheet name, the file name will be used as sheet name (usual way to do that).
Connections ? hierarchical pins
You will create here points of connection (hierarchy pins) for the symbol which has been just created.
These points of connection are similar to normal component pins, with however the possibility to connect a complete bus with only one point of connection.
There are two ways to do this:
- Place the different pins before drawing the sub-sheet (manual placement).
- Place the different pins after drawing the sub-sheet, and the global labels (semi-automatic placement).
The second solution is quite preferable.
Manual placement:
- To select the tool [[Image:]].
- Click on the hierarchy symbol where you want to place this pin.
See below an example of the creation of the hierarchical pin called ｡ﾈCONNEXION｡ﾉ.
[[Image:]]
You can define its graphical attributes, and size or later, by editing this pin sheet ( Right click and select Edit in the PopUp menu).
Various pin symbols are available :
- Input
- Output
- BiDir
- Tri State
- Not Specified
These pin symbols are only graphic enhancements, and have no other role.
Automatic placement:
- Select the tool [[Image:]].
- Click on the hierarchy symbol from where you want to import the pins corresponding to global labels placed in the corresponding schematic. A hierarchical pin appears, if a new global label exists, i.e. not corresponding to an already placed pin.
- Click where you want to place this pin.
All necessary pins can thus be placed quickly and without error. Their aspect is in accordance with corresponding global labels.
Connections - hierarchical labels
Each pin of the sheet symbol just created, must correspond to a label called hierarchical Label in the sub-sheet. Hierarchical labels are similar to labels, but they provide connections between sub-sheet and root sheet. The graphical representation of the two complementary labels (pin and HLabel) is similar. Hierarchical labels creation is made with the tool [[Image:]].
See below a root sheet example:
[[Image:]]
Notice pins TRANSF1 and TRANSF2, connected to connector JP3.
Here are the corresponding connections in the sub-sheet :
[[Image:]]
You find again, the two corresponding hierarchical labels, providing connection between the two hierarchical sheets.
Note
You can use hierarchical labels and hierarchy pins to connect two buses, according to the syntax (Bus [N. .m]) previously described.
Labels, hierarchical labels, global labels and invisible power pins
Here are some comments on various ways to provide connections, others than wire connections.
Simple labels
Simple labels have a local capacity of connection, i.e. limited to the schematic sheet where they are placed. This is due to the fact that :
- Each sheet has a sheet number.
- This sheet number is associated to a label.
Thus, if you place the label ｡ﾈTOTO｡ﾉ in sheet n｡・3, in fact the true label is ｡ﾈTOTO_3｡ﾈ. If you also place a label ｡ﾈTOTO｡ﾉ in sheet n｡・1 ( root sheet) you place in fact a label called ｡ﾈTOTO_1｡ﾈ, different from ｡ﾈTOTO_3｡ﾈ. This is always true, even if there is only one sheet.
Hierarchical labels
What is said for the simple labels is also true for hierarchical labels.
Thus in the same sheet, a HLabel ｡ﾈTOTO｡ﾉ is considered to be connected to a local label ｡ﾈTOTO｡ﾉ, but not connected to a HLabel or label called ｡ﾈTOTO｡ﾉ in another sheet.
However a HLabel is considered to be connected to the corresponding SheetLabel symbol in the hierarchical symbol placed in the root sheet.
Invisible power pins
It was seen that invisible power pins were connected together if they have the same name. Thus all the power pins declared ｡ﾈInvisible Power Pins｡ﾈ and named VCC are connected and form the equipotential VCC, whatever the sheet they are placed on.
This means that if you place a VCC label in a sub-sheet, it will not be connected to VCC pins, because this label is actually VCC_n, where n is the sheet number.
If you want this label VCC to be really connected to the equipotential VCC, it will have to be explicitly connected to an invisible power pin, thanks to a VCC power port.
Global labels
Global labels that have an identical name are connected across the whole hierarchy.
(power labels like vcc ... are global labels)
Complex Hierarchy
Here is an example. The same schematic is used twice (two instances). The two sheets share the same schematic because the file name is the same for the two sheets ("other_sheet.sch"). But the sheet names must be different.
Flat hierarchy
You can create a project using many sheets, without creating connections between these sheets (flat hierarchy) if the next rules are repsected:
- You must create a root sheet containing the other sheets, which acts as a link between others sheets.
- No explicit connections are needed.
- All connections between sheets will use global labels instead of hierarchical labels.
Here is an example of a root sheet.
[[Image:]]
Here is the two pages, connected by global labels.
[[Image:]]
[[Image:]]
| Look at global labels | [[Image:]] |