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In electronic design, a netlist is a description of the connectivity of an electronic circuit. A single netlist is effectively a collection of several related lists. In its simplest form, a netlist consists of a list of the terminals ("pins") of the electronic components in a circuit and a list of the electrical conductors that interconnect the terminals. A net is a conductor that interconnects two or more component terminals. 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, nets, and perhaps some attributes. 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. Netlists can be ''physical'' or ''logical'', ''instance-based'' or ''net-based'', and ''flat'' or ''hierarchical''. The latter can be either ''folded'' or ''unfolded''. ==Contents and structure of a netlist== 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." Thus, each instance has a "master", or "definition". These definitions will usually list the connections that can be made to that kind of device, and some basic properties of that device. These connection points are called "ports" or "pins", among several other names. An "instance" could be anything from a MOSFET transistor or a bipolar transistor, to a resistor, capacitor, or integrated circuit chip. Instances have "ports". In the case of a vacuum cleaner, these ports would be the three metal prongs in the plug. Each port has a name, and in continuing the vacuum cleaner example, they might be "Neutral", "Live" and "Ground". Usually, each instance will have a unique name, so that if you have two instances of vacuum cleaners, one might be "vac1" and the other "vac2". Besides their names, they might otherwise be identical. Nets are the "wires" that connect things together in the circuit. There may or may not be any special attributes associated with the nets in a design, depending on the particular language the netlist is written in, and that language's features. Instance based netlists usually provide a list of the instances used in a design. Along with each instance, either an ordered list of net names is provided, or a list of pairs provided, of an instance port name, along with the net name to which that port is connected. In this kind of description, the list of nets can be gathered from the connection lists, and there is no place to associate particular attributes with the nets themselves. SPICE is an example of instance-based netlists. Net-based netlists usually describe all the instances and their attributes, then describe each net, and say which port they are connected on each instance. This allows for attributes to be associated with nets. EDIF is probably the most famous of the net-based netlists. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Netlist」の詳細全文を読む スポンサード リンク
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