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

       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  mul-
	      tiplied 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 mean-
	      ing 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	termi-
	      nals 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 in-
	      formation	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  ca-
	      pacitance	 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 neg-
	      ative 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/der-

       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)

3rd Berkeley Distribution					  NETCHANGE(5)


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