Provided by: irsim_9.7.74-1_i386 bug


       netchange - format of netchange files read by irsim.


       A  netchange  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 understood.

       | any text
              Lines beginning with a vertical bar are treated as comments  and
              ignored by the program.

       add type gate source drain length width [area]
              Add  a  new  transistor of type to the network.  Currently, type
              may be:
                     n   n-channel enhancement transistor.
                     p   p-channel enhancement transistor.
                     d   depletion transistor (for NMOS).

              The names of the nodes to which the gate, source, and  drain  of
              the  transistor  are  connected  are  given by gate, source, and
              drain respectively.  The length and width of the transistor  are
              given  by length and width respectively.  The area parameter, if
              given, will use that number as the area for calculating the gate
              capacitance.   Length and width should be given in lambda units,
              area should be in lambda ^2  units,  these  will  internally  be
              multiplied  by  the  LAMBDA factor from the configuration (.prm)

       delete type gate source drain length width [area]
              Delete an existing transistor from the net.  All the  parameters
              have the same meaning as for the add command.

       move type gate source drain length width [area] g s d
              Move  an  existing  transistor to a new location the net.  type,
              gate, source, drain, length,  width,  and  area  have  the  same
              meaning  as  for  the add command.  g, s, and d are the names of
              nodes to which the gate, source and drain should  be  connected.
              If  a particular terminal(s) is not to be re-connected, the name
              can be specified using an "*".  Any or all of g, s, and d may be
              "*".   For  example, to move the gate of an n-channel transistor
              from node old to new the following command would be used:

                 m n old src_node drn_node 4 2.2 new * *

              Note that the drain and  source  terminals,  and  the  g  and  s
              terminals  are interchangeable; the simulator will know if these
              are swapped.  So the last example could also have been written:

                 m n old drn_node src_node 4 2.2 new * *

       capacitance node value
              Change the capacitance of a node by value picofarads.  Value may
              be negative, thereby decreasing the node's capacitance.  Node is
              the node name.

       N node metal-area poly-area diff-area diff-perimeter
              Change the capacitance of node  using  the  area  and  perimeter
              information  of  the  metal,  polysilicon, and diffusion layers.
              All the parameters should be in lambda (or lambda^2  for  areas)
              units,  they  will  internally  be  converted to the appropriate
              capacitance as defined in the configuration  file.   The  values
              can be negative to decrease the capacitance.

       M node M2A M2P MA MP PA PP DA DP PDA PDP
              Change  the capacitance of node, using the following geometrical

                     M2A   area of 2nd-level metal
                     M2P   perimeter of 2nd-level metal
                     MA    area of 1st-level metal
                     MP    perimeter of 1st-level metal
                     PA    area of polysilicon
                     PP    perimeter of polysilicon
                     DA    area of n-diffusion
                     DP    perimeter of n-diffusion
                     PDA   area of p-diffusion
                     PDP   perimeter of p-diffusion

              All perimeter values should be  in  lambda  units,  area  values
              should be in lambda^2 units.  The perimeter measures are half of
              the actual total perimeter  (i.e.,  they  are  the  sum  of  the
              lengths  of  the  top  and  one side).  Again, the values may be
              negative to decrease the capacitance of the node.

       threshold node low high
              Change the threhsold voltages of node.  Low and high  should  be
              in  normalized voltage units (i.e. floating-point numbers in the
              range 0.0 to 1.0).

       Delay node tplh tphl
              Change the delays for node to be tplh  nanoseconds  for  low-to-
              high  transistions,  and  tphl ns. for high-to-low transistions.
              These    should    be    absolute    numbers,    not    relative

       NOTE: For  all commands, only the first letter is significant, the rest
             of the string will be ignored.  They  are  only  shown  here  for


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


       irsim(5) sim(5) presim(1)