Plugin: End-Circuits

End-Circuit SVG Images

End-circuits need to be available in Scalable Vector Graphics (SVG) format as files in the same directory as the EDB database. We require that the file names of the SVG images do not contain spaces, commas, and semicolons.

Every SVG file can be referenced by an arbitrary number of components, e.g., if multiple ECUs have the same end-circuits, they can share the same SVG files. Each component can refer to several end-circuit files, each showing the relevant part for a cavity or a group of related cavities. Splitting the internals of an ECU component into several parts has the advantage that EEvision can display the relevant end-circuit part of the selected pins only, leading to clearer schematics.

For connecting the end-circuit image to the component's cavities, placeholder strings in the SVG image are used. We support two different kinds of placeholders:

• Port names are replaced with the name of the connector and cavity they are connected to. Port names always start with an exclamation mark and consist otherwise only of capital letters and digits. For instance, the string !INPUT is such a port name. If it is connected in the EDB with cavity 1 of connector A, then the string !INPUT is replaced by EEvision with A-1 and a shape denoting the signal direction (if available in the EDB).
• Parameters are replaced by values defined in the EDB database. For instance, if two end-circuits differ only by the value of resistors and capacitors, these values can be modeled as parameters that are replaced with the concrete values. This mechanism allows to use a single SVG file for both instantiations. Parameters can also be used for internationalization: If all language-specific strings are replaced by parameters, the EDB can provide the translation for the selected language. Parameter strings start with a space plus a question mark and contain otherwise only capital letters and digits. For instance, ␣?RES1 is a valid parameter string.

Below we present examples of end-circuit SVG files with port names and parameter strings.

Highlighting in End-circuit Images

The plugin supports highlighting of end-circuit parts connected to a selected pin. For this purpose a simple color coding scheme is used: All parts of the end-circuit that have the same color as a port string (of the form !PORT) are highlighted (with the Nlview selection color) when a pin connected to that port is selected. The colors of ports that are not connected to a selected pin are replaced by black. The remaining colors in the image are not changed.

Specification of End-Circuits in the EDB

For connecting a cavity to an end-circuit, the cavity needs to have an attribute with the name “␣ecfile” (with a leading space, indicating that the attribute is an internal attribute to EEvision). The value of this attribute is a semicolon-separated list of connection data.

Each piece of connection data is a list of four entries that are separated with commas; in case of only one connection the attribute looks as follows:

   ␣ecfile = filename,instID,portname,direction

The four fields have the following meaning:

• filename is the name of the SVG file with the end-circuit. The extension .svg can be omitted.
• instID Multiple instances of the same SVG file can be used in the same component. For instance, if a component contains four fuses and the corresponding SVG file depicts a single fuse, we can instantiate it four times. Each instance then gets a different instance ID that is unique within the component. The instance ID can be an arbitrary string consisting of digits and letters. See below for examples how to use multiple instances in one component.
• portname is the name of the port in the SVG image which the cavity is connected. The leading exclamation mark is omitted, i.e., if in the SVG image the port is named !INPUT, then the port name in the “␣ecfile” attribute is simply INPUT.
• direction For replacing the port names and drawing the correct port symbols, we need to know position of the port name w.r.t. the corresponding signal line. Possible values are
  • left – the port name is left of the corresponding line;
  • right – the port name is right of the line;
  • top – the port name is vertically above the line;
  • bottom – the port name is vertically below the line.

For parameter substitution, the cavity attributes whose name start with “␣?” are used: If the cavity has an attribute ␣?RES1 = 10 Ω then the parameter ?RES1 in the SVG image is replaced with the value 10 Ω in all end-circuit instances the cavity is connected to. It is sufficient to specify the attribute once at a single cavity. However, if the attribute is repeated at multiple cavities connected to the same end-circuit instance, the values of all repetitions must be consistent.

If a cavity is connected to multiple end-circuit instances, but the parameter should be substituted only in some of them, the attribute name must include the instance ID, followed by a colon.

Assume that the end-circuit image opv.svg contains a parameter ?RES, denoting the value of a resistor. Further assume that a cavity is connected to two instances of this end-circuit image:

    ␣ecfile = opv,1,IN,left;opv,2,IN,left

If ?RES should be replaced with 100 Ω in the first instance, but 250 Ω in the second, we can use the following cavity attributes:

    ␣?1:RES = 100 Ω
    ␣?2:RES = 250 Ω

Examples

Example 1

Figure 1 shows a simple end-circuit example, where the ECU only references a single SVG file and each cavity of the ECU is connected to one port of the end-circuit.

Fig. 1(a): An end-circuit SVG file: opv.svg

Cavity	Attribute	Value
1	␣ecfile	opv,1,IN1,left
	␣?R1	10 kΩ
	␣?R2	15 kΩ
	␣?R3	20 kΩ
	␣?R4	15 kΩ
	␣?C1	5 μF
	␣?C2	10 μF
2	␣ecfile	opv,1,IN2,left
3	␣ecfile	opv,1,OUT1,right
4	␣ecfile	opv,1,OUT2,right

Fig. 1(b): The cavity attributes at component C1, connector A

Fig. 1(c): The resulting schematics when cavity 1 is selected

In Fig. 1(a), the SVG file is shown. The ports are named !IN1, !IN2, !OUT1, and !OUT2. Note that the port names all start with “!”. The image additionally contains six parameter strings: ?R1, ..., ?R4, ?C1, and ?C2. All parameter strings start with “?”. Note that all port names and parameter strings consist – apart from “!” and “?” – of capital letters and digits only.

The table in Fig. 1(b) lists the necessary attributes that connect the SVG image with the ECU component. Each cavity needs an “␣ecfile” attribute; here all refer to the same SVG file (opv.svg). The file extension can be omitted. All refer to the same instance of the end-circuit template. In the example, the instance identifier is “1”. The third entry is the port name (IN1, etc.) to which the cavity is connected; the leading exclamation mark “!” is omitted. Finally, the “␣ecfile” attribute specifies on which side of the corresponding line in the SVG file the port is placed: IN1 and IN2 are on the left, OUT1 and OUT2 are on the right.

Additionally, the values of the parameters need to be specified. They can be attached to an arbitrary cavity that is connected to the end-circuit instance. Here we specified them at cavity 1.

The resulting schematics is shown in Fig. 1(c). We obtain this result when we select cavity 1 or the wire connected to it. We can see that the port names have been replaced by the corresponding connector name and cavity name. The shape of the generated port symbol depends on the flags of the cavity: -in, -out, both -in and -out, or no flag. Also all parameter have been replaced by their value. Since cavity 1 is selected, the corresponding end-circuit port A-1 is highlighted.

Example 2

A more complicated example is shown in Fig. 2. It uses three end-circuit instances of two different SVG files trans.svg and opv2.svg. The corresponding pin attributes are listed in the following table. Note that we do not use parameter substitution here.

The file trans.svg (see Fig. 2(a)) contains color-coded ports. For instance, whenever a pin connected to port !IN1 is selected, then all parts colored in red will be highlighted. All colors (here: blue and green) of ports without a selected pin are replaced by black. The remaining colors (here: violet for the transistor labels) are not changed.

Fig. 2(a): Image file trans.svg.

Fig. 2(b): Image file opv2.svg.

Cavity	Attribute	Value
1	␣ecfile	opv2,3,IN2,left
2	␣ecfile	trans,2,OUT,right
4	␣ecfile	trans,1,IN1,left;trans,2,IN2,left;opv,3,IN1,left
8	␣ecfile	trans,1,OUT,right
9	␣ecfile	trans,1,IN1,left
10	␣ecfile	trans,2,IN1,left
11	␣ecfile	opv2,3,OUT2,right
12	␣ecfile	trans,1,IN1,left;trans,2,IN1,left
13	␣ecfile	opv2,3,OUT1,right

Fig. 2(c): The ␣ecfile attributes at the cavities of component B46 in the EDB.

Fig. 2(d): The resulting schematics after selecting cavity 4.

We have three end-circuit instances, two of the file trans.svg (with instance IDs 1 and 2) and one of opv2.svg (with instance ID 3). Cavity 4 is connected to three ports, cavity 12 to two ports.

Summary

The EEvision end-circuit plugin provides the following features:

• Several cavities can connect to the same end-circuit port.
• One cavity can connect to several end-circuit ports.
• The scale factor for different end-circuit SVGs is determined automatically from the font size of the port names. The SVG images are scaled such that the font size of the images are the same.
• Parameter substitution can be used for internationalization and adapting device parameters.
• If an SVG image has ports only on one side (left/right), we flip it if necessary such that the ports are on the same side as the majority of the cavities they are connected to.
• The port shape in the displayed image reflects the signal direction of the cavities (in/out/inout).
• We highlight the port connected to selected cavities. Multiple selections are supported.