PAL20X8                                              PAL DESIGN SPECIFICATION
P7044                                                    NADIA SACHS 08/14/81
32-BIT CRC (CYCLICAL REDUNDANCY CHECKING) ERROR DETECTION, CHIP 4
MMI SUNNYVALE, CALIFORNIA
CLK INIT C IN /Q23 NC NC NC /CHK1 /CHK2 /CHK3 GND
/OC /OUT /Q31 /Q30 /Q29 /Q28 /Q27 /Q26 /Q25 /Q24 /CHECK VCC


IF(VCC) CHECK  =   CHK1* CHK2* CHK3* Q24* Q25* Q26*/Q27   ;CHECK
               *                    /Q28*/Q29* Q30* Q31   ;ERROR

Q24   :=   Q23                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q25   :=   Q24                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q26   :=   Q25                                            ;SHIFT
       +   INIT                                           ;INITIALIZE
      :+: /INIT* C* IN*/Q31                               ;MODULO-2
       +  /INIT* C*/IN* Q31                               ;ADDITION

Q27   :=   Q26                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q28   :=   Q27                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q29   :=   Q28                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q30   :=   Q29                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

Q31   :=   Q30                                            ;SHIFT
       +   INIT                                           ;INITIALIZE

IF(VCC) OUT =  Q31*/C                                     ;SERIAL
            + /IN * C                                     ;OUT


FUNCTION TABLE

CLK /OC INIT C IN CHK1 CHK2 CHK3 Q23 Q31 Q30 Q29 Q28 Q27 Q26 Q25 Q24 OUT CHECK

;                                  Q   QQQQQQQQ
;                            CHK   2   33222222
;CLK   /OC   INIT   C   IN   123   3   10987654   OUT   CHECK
--------------------------------------------------------------
  C     L     H     X   L    XXX   X   HHHHHHHH    X      X
  C     L     L     H   L    XXX   H   HHHHHLHH    H      X
  C     L     L     H   L    XXX   L   HHHHLLHL    H      X
  C     L     L     H   L    XXX   H   HHHLLLLH    H      X
  C     L     L     H   L    XXX   H   HHLLLHHH    H      X
  C     L     L     H   L    XXX   H   HLLLHLHH    H      X
  C     L     L     H   L    XXX   H   LLLHLLHH    H      X
  C     L     L     H   L    XXX   H   LLHLLHHH    H      X
  C     L     L     H   L    XXX   L   LHLLHHHL    H      X
  C     L     L     H   L    XXX   L   HLLHHHLL    H      X
  C     L     L     H   L    XXX   L   LLHHHHLL    H      X
  C     L     L     H   L    XXX   H   LHHHHLLH    H      X
  C     L     L     H   L    XXX   H   HHHHLLHH    H      X
  C     L     L     H   L    XXX   H   HHHLLLHH    H      X
  C