DpgenRom4

• Name : DpgenRom4 - 4 words ROM Macro-Generator
• Synopsys :

  Generate ( 'DpgenRom4', modelname
           , param = { 'nbit'     : n
                     , 'val0'     : constVal0
                     , 'val1'     : constVal1
                     , 'val2'     : constVal2
                     , 'val3'     : constVal3
                     , 'physical' : True                   
                     }
           )
  

• Description : Generates a n bits 4 words optimized ROM named modelname.
• Terminal Names :
  • sel1 : upper bit of the address of the value (input, 1 bit)
  • sel0 : lower bit of the address of the value (input, 1 bit)
  • q : the selected word (output, n bits)
  • vdd : power
  • vss : ground
• Parameters : Parameters are given in the map param.
  • nbit (mandatory) : Defines the size of the generator
  • val0 (mandatory) : Defines the first word
  • val1 (mandatory) : Defines the second word
  • val2 (mandatory) : Defines the third word
  • val3 (mandatory) : Defines the fourth word
  • physical (optional, default value : False) : In order to generate a layout
• Behavior :

  q <= WITH sel1 & sel0 SELECT constVal0  WHEN B"00",
                               constVal1  WHEN B"01",
                               constVal2  WHEN B"10",
                               constVal3  WHEN B"11";
  

• Example :

  from stratus import *
  
  class inst_rom4 ( Model ) :
  
    def Interface ( self ) :
      self.sel0 = SignalIn  (    "sel0", 1 )
      self.sel1 = SignalIn  (    "sel1", 1 )
      self.q    = SignalOut ( "dataout", 4 )
      
      self.vdd = VddIn ( "vdd" )
      self.vss = VssIn ( "vss" )
      
    def Netlist ( self ) :
      Generate ( 'DpgenRom4', 'rom4_0b1010_0b1100_0b1111_0b0001'
               , param = { 'nbit'     : 4
                         , 'val0'     : "0b1010"
                         , 'val1'     : "0b1100"
                         , 'val2'     : "0b1111"
                         , 'val3'     : "0b0001"
                         , 'physical' : True
                         }
               )      
      self.I = Inst ( 'rom4_0b1010_0b1100_0b1111_0b0001', 'inst'
                    , map = { 'sel0' : self.sel0
                            , 'sel1' : self.sel1
                            , 'q'    : self.q
                            , 'vdd'  : self.vdd
                            , 'vss'  : self.vss
                            }
                    )
    
    def Layout ( self ) :
      Place ( self.I, NOSYM, Ref(0, 0) )