16. Glossary

Subcircuit	Base object of a hierarchical description. The subcircuit is defined by its components, which may be elementary objects (transistors, resistances, capacitances...) or instances of other subcircuits.
Cell	Predefined subcircuit, only containing elementary objects, that may be selected and arranged to create custom or semi-custom integrated circuit.
Instance	Call of a subcircuit in a specific context
(Logical) Signal	Object carrying logical information between instances or elementary objects
Connector	Object carrying the logical information of a signal through the interface of an instance.

RC network	Connected set of R and C devices
Net	Individual RC network linked to a logical signal. The RC network presents a resistive path between connectors of connected instances. Capacitances are substrate or coupling ones.
Node	Single point in a RC network

(Timing) Signal	Point of the circuit where the timing propagation of the logical information is measured. Whereas the logical signal is linked to a net, the timing signal is linked to a node. Indeed, as propagation delays in RC networks must be taken into account, it is necessary to measure the timing propagation of the logical information on several points of the net. The methodology in HITAS is to associate a timing signal with each terminal node of a net. As a result, several timing signals may exist where only one logical signal exist.
Event	Rising or falling logical transition on a timing signal
Reference point	Timing signal where timing checks must be performed: input or output connectors, latch, precharge, latch or precharge commands.
Path	List of timing signals, from reference point to reference point, through which logical information is carried
Break point	User defined reference point