PAL16R6                                        PAL DESIGN SPECIFICATION
CTMAPSEL                                  Daniel Edmunds     6-NOV-1990
Level 1 Calorimeter Trigger Map Select PAL
MSU/HEP
CLOCK DATIN1 DATIN2 DATIN3 DATIN4 DATIN5 DATIN6 EXTENB EXTBIT GROUND /RDREG
ROMBIT READBACK FORCEHI EXTENB2NDENB EXTBIT1STENB FORCE2ND FORCE1ST /BITOUT VCC


/FORCE1ST      :=  /DATIN1
/FORCE2ND      :=  /DATIN2
/EXTBIT1STENB  :=  /DATIN3
/EXTENB2NDENB  :=  /DATIN4
/FORCEHI       :=  /DATIN5
/READBACK      :=  /BITOUT

IF(VCC)  BITOUT  =  FORCE1ST      * /ROMBIT
                 +  FORCE2ND      *  ROMBIT
                 +  EXTBIT1STENB  * /ROMBIT  *  EXTBIT
                 +  EXTENB2NDENB  *  ROMBIT  *  EXTENB
                 +  FORCEHI


DESCRIPTION

This is the MMI format source file for the pal used in the L1 Calorimeter
Trigger Lookup Memory Map Select lines.

This PAL is used with a timing PROM that is LOW during the 1st lookup and
HIGH during the 2nd lookup.

This PAL uses 6 registers to hold the following information:

   Data                           Pin             Pin
   Line    Signal Name       Number Input    Number Output
   ----  ----------------    ------------    -------------
     1     FORCE1ST                2               18
     2     FORCE2ND                3               17
     3     EXTBIT1STENB            4               16
     4     EXTENB2NDENB            5               15
     5     FORCEHI                 6               14
     6     READBACK                7               13


Data
Line                             Function
----  -----------------------------------------------------------------------
  1   If Set --> Force the Map Select line to go HIGH during the 1st Lookup.
  2   If Set --> Force the Map Select line to go HIGH during the 2nd Lookup.
  3   If Set and if EXT BIT is HI --> Force Map Select HI during 1st Lookup.
  4   If Set and if EXT ENB is HI --> Force Map Select HI during 2nd Lookup.
  5   If Set --> Force the Map Select line to go HIGH all the time.
  6   After loading the PAL register this line Reads back the Map Select line.


Data Line #6, READBACK, is set equal to the state of the Map Select output
line each time the PAL is loaded (written to).  This is a "Read Only" bit.


There are 3 inputs signals to this PAL:

                                      Signal      Pin
                Function               Name      Number
       ---------------------------   --------   --------
        External Enable               EXTENB     pin 8
        External Signal Bit Input     EXTBIT     pin 9
        PROM Bit Input                ROMBIT     pin 12


The final Output Signal from this PAL goes to the TTL to ECL driver chip
to drive this timing signal off card.  This is BITOUT, pin 19.

The Clock, CLOCK, pin 1, is used to Load the PAL's data registers.

The Output Enable is used to enable the PAL's tri-state output
buffers, RDREG, pin 11.

6-NOV-1990