1NETCHANGE(5)                  IRSIM User's Manual                 NETCHANGE(5)
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NAME

6       netchange - format of netchange files read by irsim.
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DESCRIPTION

10       A  netchange  file  consists of a series of lines, each of which begins
11       with a key letter.  The key letter beginning a line determines how  the
12       remainder  of  the  line is interpreted.  The following are the list of
13       key letters understood.
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15       | any text
16              Lines beginning with a vertical bar are treated as comments  and
17              ignored by the program.
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19       add type gate source drain length width [area]
20              Add  a  new  transistor of type to the network.  Currently, type
21              may be:
22                     n   n-channel enhancement transistor.
23                     p   p-channel enhancement transistor.
24                     d   depletion transistor (for NMOS).
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26              The names of the nodes to which the gate, source, and  drain  of
27              the  transistor  are  connected  are  given by gate, source, and
28              drain respectively.  The length and width of the transistor  are
29              given  by length and width respectively.  The area parameter, if
30              given, will use that number as the area for calculating the gate
31              capacitance.   Length and width should be given in lambda units,
32              area should be in lambda^2 units, these will internally be  mul‐
33              tiplied by the LAMBDA factor from the configuration (.prm) file.
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35       delete type gate source drain length width [area]
36              Delete  an existing transistor from the net.  All the parameters
37              have the same meaning as for the add command.
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39       move type gate source drain length width [area] g s d
40              Move an existing transistor to a new location  the  net.   type,
41              gate, source, drain, length, width, and area have the same mean‐
42              ing as for the add command.  g, s, and d are the names of  nodes
43              to  which  the gate, source and drain should be connected.  If a
44              particular terminal(s) is not to be re-connected, the  name  can
45              be  specified  using  an  "*".  Any or all of g, s, and d may be
46              "*".  For example, to move the gate of an  n-channel  transistor
47              from node old to new the following command would be used:
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49                 m n old src_node drn_node 4 2.2 new * *
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51              Note that the drain and source terminals, and the g and s termi‐
52              nals are interchangeable; the simulator will know if  these  are
53              swapped.  So the last example could also have been written:
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55                 m n old drn_node src_node 4 2.2 new * *
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57       capacitance node value
58              Change the capacitance of a node by value picofarads.  Value may
59              be negative, thereby decreasing the node's capacitance.  Node is
60              the node name.
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62       N node metal-area poly-area diff-area diff-perimeter
63              Change  the  capacitance  of  node  using the area and perimeter
64              information of the metal,  polysilicon,  and  diffusion  layers.
65              All  the  parameters should be in lambda (or lambda^2 for areas)
66              units, they will internally  be  converted  to  the  appropriate
67              capacitance  as  defined  in the configuration file.  The values
68              can be negative to decrease the capacitance.
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70       M node M2A M2P MA MP PA PP DA DP PDA PDP
71              Change the capacitance of node, using the following  geometrical
72              information:
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74                     M2A   area of 2nd-level metal
75                     M2P   perimeter of 2nd-level metal
76                     MA    area of 1st-level metal
77                     MP    perimeter of 1st-level metal
78                     PA    area of polysilicon
79                     PP    perimeter of polysilicon
80                     DA    area of n-diffusion
81                     DP    perimeter of n-diffusion
82                     PDA   area of p-diffusion
83                     PDP   perimeter of p-diffusion
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85              All  perimeter  values  should  be  in lambda units, area values
86              should be in lambda^2 units.  The perimeter measures are half of
87              the  actual  total  perimeter  (i.e.,  they  are  the sum of the
88              lengths of the top and one side).  Again, the values may be neg‐
89              ative to decrease the capacitance of the node.
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91       threshold node low high
92              Change  the  threhsold voltages of node.  Low and high should be
93              in normalized voltage units (i.e. floating-point numbers in  the
94              range 0.0 to 1.0).
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96       Delay node tplh tphl
97              Change  the  delays  for node to be tplh nanoseconds for low-to-
98              high transistions, and tphl ns.  for  high-to-low  transistions.
99              These  should  be absolute numbers, not relative increments/der‐
100              crements.
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102       NOTE: For all commands, only the first letter is significant, the  rest
103             of  the  string  will  be  ignored.  They are only shown here for
104             clarity.
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BUGS

108       This is an experimental interface for the incremental simulator and  is
109       very likely to change in the future.
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SEE ALSO

113       irsim(5) sim(5) presim(1)
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1173rd Berkeley Distribution                                         NETCHANGE(5)
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