NAME

       netchange - format of netchange files read by irsim.

DESCRIPTION

       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) file.

       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 information:

                     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 transitions, and tphl ns. for
              high-to-low transitions.  These should be absolute numbers, not relative increments/dercrements.

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

BUGS

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

SEE ALSO

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