Wiring > Modular Wiring Synthesis

Option Expressions for

Negated Options

It is quite common for a harness to contain wiring that is only required when an option is NOT present (for example, !ABS – we call this a negated option). Normally, there will be a separate harness level containing the wires that support the option from the harness level that supports the negated option. However, in some cases it is required that both sets of wires are included on the same harness level. This is not easily supported since if the harness level states that it supports the option, the negated wires will not be included. You can use a “Splice exclusive wire” constraint to support this special use-case. As well as creating a splice between the exclusive wires, this will identify the harness as requiring a post processing step to add to its option expression generation.

This post processing step is a guided alteration to the option expression on certain wires within the harness. The alteration updates wiring option expressions to match their intended giveaway such that they will appear on the correct derivative designs after synchronization with Capital Harness Designer.

Figure 185: Negated Option Example

In this example, the following constraint is used:

Treat options ABS, !ABS as not exclusive during synthesis in configuration

Synthesis therefore modified the option expression on the negated wire so that ABS and !ABS are supported on a single harness level and !ABS can be given away.

If MWS has run already and wires exist, you can use the design rule check 'Wires with negated options' to identify options that may require this special handling. It reports such statements as 'Wire WIRE25 has negated options A'.

For wires in harnesses with the constraint, MWS runs the post processing step.

The system report changes to option expressions on objects in an Options tab in the Output Window located at the bottom of the application window.

Caution

The system deletes bypass wires that are no longer valid due to changes in option expressions.

The post processing manipulates bypass wires and normal (that is, non-bypass) wires differently:

Constraint Applied to Harness	Option Expression on Wire before Post Processing	Option Expression on Wire after Post Processing
Treat options	Normal wire: !	Normal wire: (<!option>
Treat options A,!A as not exclusive during synthesis in configuration LHD	Normal wire: !A Bypass wire: A	Normal wire: (!A
Treat options A,!A as not exclusive during synthesis in configuration	Normal wire: !A Bypass wire: A	Normal wire: (!A

Parent Topic:

Modular Wiring Synthesis