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

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 transistions, and tphl ns. for high-to-low transistions.  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  clar-
	     ity.

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)

3rd Berkeley Distribution													      NETCHANGE(5)