PLA(5OCTTOOLS)					   PLA(5OCTTOOLS)



NAME
       pla  -  Format  for  physical  description of Programmable
       Logic Arrays.

SYNOPSIS
       pla

DESCRIPTION
       This format is used by programs which manipulate	 plas  to
       describe	 the  physical	implementation.	  Lines beginning
       with a `#' are comments and are ignored.	 Lines	beginning
       with  a	`.'  contain  control  information about the pla.
       Currently, the control information is given in the follow­
       ing order:
	    .i	
	    .o	
	    .p	
	    and optionally,
	    .na (the name to be used for the pla)

       What  follows  then  is	a  description	of the AND and OR
       planes of the pla with one line per product term.  Connec­
       tions in the AND plane are represented with a `1' for con­
       nection to the non-inverted input line and a `0' for  con­
       nection	to  the inverted input line.  No connection to an
       input line is indicated with 'x', 'X',  or  '-'	with  '-'
       being  preferred.   Connections	in the OR plane are indi­
       cated by a '1' with no  connection  being  indicated  with
       'x', 'X', '0', or '-' with '-' being preferred.	Spaces or
       tabs may be used freely and are ignored.

       The end of the pla description is indicated with:
	    .e

       Programs capable	 of  handling  split  and  folded  arrays
       employ the following format:


	      AND PLANE

		     Column (1) Contact to input  (2) No contact to input

		     (1)     (2)
		      1	      -	    Normal contacts, no splits or folds
		      !	      _		 Split below
		      ;	      ,		 Fold to right
		      :	      .		 Split below and fold to right

	      OR PLANE

		     Column (1) Contact to output  (2) No contact to output

		     (1)     (2)
		      I	      ~		 Normal contacts, no splits or folds
		      i	      =	    Split below
		      |	      '		 Fold to right
		      j	      "		 Split below and fold to right

	      ADDITIONAL ELEMENTS

		      *	       Input buffer
		      +	       Output buffer
		      D	       Depletion load associated with product term
		      N	       No depletion load associated with product term


       Note  that the decoding function of the AND plane is sepa­
       rated from the specification of	its  connectivity.   This
       makes the AND and OR plane specifications identical.

       These  programs	handle	the  following	more  general set
       of .parameters:

	    .il	 
	    .ir	 
	    .ol	 
	    .or	 
	    .p	

	    .ilt  
	    .ilb  
	    .irt  
	    .irb  
	    .olb  
	    .olt  
	    .orb  
	    .ort  
	    .pl	 
	    .pr	 

       The first group of  parameters  must  precede  the  second
       group.  If there is only one AND or OR plane it is assumed
       to be the left one and the  companion .parameters  may  be
       shortened by dropping their (left,right) designation char­
       acter.

       In order to better deal with folded and	split  PLAs,  the
       following .parameters are proposed:

	    .ig	 
	    .og	 

	    .ins  
	    .inf  
	    .ons  
	    .onf  


       In  order  to  build  finite  state  machines, the follow­
       ing .parameters are proposed:

	    .iltf  
	    .ilbf  
	    .irtf  
	    .irbf  
	    .oltf  
	    .olbf  
	    .ortf  
	    .orbf  

	    .ilr  
	    .irr  
	    .olrf  
	    .orrf  

       The .XXXf parameters must occur in pairs,  with	the .oXXf
       line first.  Input and output terms must occur on the same
       side (top, bottom) of the PLA.	Feedback  terms	 must  be
       given   in   ascending  order.	The  re-order .parameters
       simplify feedback routing.


SEE ALSO
       espresso(1OCTTOOLS), espresso(5OCTTOOLS), misII(1OCTTOOLS)



			     8/23/81		   PLA(5OCTTOOLS)