Using VHDL-AMS Models

Twin Builder provides several libraries containing VHDL-AMS components developed according to IEEE 1076.1 (VHDL Analog and Mixed Signal Extensions Standard) and IEEE 1076 (VHDL standard):

• Basic Elements VHDLAMS: contains common basic circuit components and blocks.
• Digital Elements: contains common basic components used for simple digital circuits.
• Tools > Transformations > OmniCasters: contains auxiliary components (called OmniCasters) that facilitate the connection of different data types and natures.

The models provided are open and can be used to derive more advanced models by copying the description to a user-defined library and editing the text to modify the model. The files can be used and distributed provided the copyright statement, included in each model description, is not removed. To access the model description, right-click the component name in the Component Libraries window and select Edit Component on the context menu to open the Edit Component dialog box. On the «Simulation Models» tab, click Edit in the Edit Model field to view (and edit) the text.

The functionality of all VHDL-AMS models is a subset of that of the equivalent Twin Builder models available in the Basic Elements library. VHDL-AMS models can be used in parallel with Twin Builder models.

The digital models operate with digital signals and can be characterized with rise time/fall time/propagation delays. They do not have any conservative nodes but can be connected with analog quantities using OmniCasters (in the Tools library).

Across and Through Quantities of Natures

VHDL-AMS models can support nature types for several physical domains. Nature types are properties of conservative nodes (also referred to as ports or terminals) of models. At least one specific nature exists for each domain. An across and a through quantity is associated with each nature. The following table links the across and through quantities for each nature type: