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SIM(5) File Formats Manual SIM(5) NAME sim - format of .sim files read by esim, crystal, etc. DESCRIPTION The simulation tools crystal(1) and esim(1) accept a circuit description in .sim format. There is a single .sim file for the entire circuit, unlike Magic's ext(5) format in which there is a .ext file for every cell in a hi- erarchical design. A .sim file consists of a series of lines, each of which begins with a key letter. The key letter beginning a line determines how the remainder of the line is interpreted. The following are the list of key letters under- stood. | units: s tech: tech format: MIT|LBL|SU If present, this must be the first line in the .sim file. It iden- tifies the technology of this circuit as tech and gives a scale fac- tor for units of linear dimension as s. All linear dimensions ap- pearing in the .sim file are multiplied by s to give centimicrons. The format field signifies the sim variant. MIT and SU are compati- ble and understood by all tools. LBL is understood only by gem- ini(1). type g s d l w x y g=gattrs s=sattrs d=dattrs Defines a transistor of type type. Currently, type may be e or d for NMOS, or p or n for CMOS. The name of the node to which the gate, source, and drain of the transistor are connected are given by g, s, and d respectively. The length and width of the transistor are l and w. The next two tokens, x and y, are optional. If present, they give the location of a point inside the gate region of the transistor. The last three tokens are the attribute lists for the transistor gate, source, and drain. If no attributes are present for a particular terminal, the corresponding attribute list may be absent (i.e, there may be no g= field at all). The attribute lists gattrs, etc. are comma-separated lists of labels. The label names should not include any spaces, although some tools can accept label names with spaces if they are enclosed in double quotes. In version 6.4.5 and later the default format produced by ext2sim is SU. In this format the attribute of the gate starting with S_ is the substrate node of the fet. The attributes of the gate, and source and substrate starting with A_, P_ are the area and perimeter (summed for that node only once) of the source and drain respec- tively. This addition to the format is backwards compatible. C n1 n2 cap Defines a capacitor between nodes n1 and n2. The value of the ca- pacitor is cap femtofarads. NOTE: since many analysis tools compute transistor gate capacitance themselves from the transistor's area and perimeter, the capacitance between a node and substrate (GND!) normally does not include the capacitance from transistor gates con- nected to that node. If the .sim file was produced by ext2sim(1), check the technology file that was used to produce the original .ext files to see whether transistor gate capacitance is included or ex- cluded; see ``Magic Maintainer's Manual #2: The Technology File'' for details. R node res Defines the lumped resistance of node node to be res ohms. This construct is only interpreted by a few programs. r node1 node2 res Defines an explicit resistor between nodes node1 and node2 of resis- tance res ohms. This construct is only interpreted by a few pro- grams. N node darea dperim parea pperim marea mperim As an alternative to computed capacitances, some tools expect the total perimeter and area of the polysilicon, diffusion, and metal in each node to be reported in the .sim file. The N construct asso- ciates diffusion area darea (in square centimicrons) and diffusion perimeter dperim (in centimicrons) with node node, polysilicon area parea and perimeter pperim, and metal area marea and perimeter mperim. This construct is technology dependent and obsolete. A node attr Associates attribute attr for node node. The string attr should contain no blanks. = node1 node2 Each node in a .sim file is named implicitly by having it appear in a transistor definition. All node names appearing in a .sim file are assumed to be distinct. Some tools, such as esim(1), recognize aliases for node names. The = construct allows the name node2 to be defined as an alias for the name node1. Aliases defined by means of this construct may not appear anywhere else in the .sim file. SEE ALSO crystal(1), esim(1), ext2sim(1), sim2spice(1), ext(5) 4th Berkeley Distribution SIM(5)
NAME | DESCRIPTION | SEE ALSO
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