Netlist

In electronic design, a netlist is a description of the connectivity of an electronic circuit. In its simplest form, a netlist consists of a list of the electronic components in a circuit and a list of the nodes they are connected to. A network (net) is a collection of two or more interconnected components. The structure, complexity and representation of netlists can vary considerably, but the fundamental purpose of every netlist is to convey connectivity information. Netlists usually provide nothing more than instances, nodes, and perhaps some attributes of the components involved. If they express much more than this, they are usually considered to be a hardware description language such as Verilog or VHDL, or one of several languages specifically designed for input to simulators or hardware compilers (such as SPICE analog simulation netlists). Netlists can be: Physical (based upon physical connections) or logical (based upon logical connections) For example, connecting three components through one terminal of one of those components would be considered a direct logical connection, whereas each would be discrete physical connections. Instance-based (clustered about a component instance) or net-based (exhaustive list of connections to a particular net) Flat (all connections are shown) or hierarchical (connections are grouped in some way; such as which physical board or layer they are connected to. Such netlists may in addition be either folded, hiding data beneath a given level of abstraction, or unfolded, being exhaustive and thus potentially equivalent in content to flat netlists.) Most netlists either contain or refer to descriptions of the parts or devices used. Each time a part is used in a netlist, this is called an "instance". These descriptions will usually list the connections that are made to that kind of device, and some basic properties of that device. These connection points are called "terminals" or "pins", among several other names.