PAL16X4                                           PAL DESIGN SPECIFICATION
P7046                                                  B. BRAFMAN 03/13/81
SYNDROME BIT GENERATOR
MMI FIELD APPLICATIONS ENGINEER YORBA LINDA, CALIFORNIA
SYNCLK D7 D6 B0 B1 B2 B3 D5 D4 GND
/OC D3 D2 A3 A2 A1 A0 D1 D0 VCC


;    IN THE ABOVE PIN LIST, THE FOLLOWING SUBSTITUTIONS HAVE BEEN
;    MADE TO ACCOMODATE THE SPECIFIC FORMAT (FIXED SYMBOLS) FOR THE
;    ARITHMETIC PALS IN PALASM:

;         D7 MEANS B7        B0 MEANS /C3  (CHECK BIT 3)
;         D6 MEANS B6        B1 MEANS /C2  (CHECK BIT 2)
;         D5 MEANS B5        B2 MEANS /C1  (CHECK BIT 1)
;         D4 MEANS B4        B3 MEANS /C0  (CHECK BIT 0)
;         D3 MEANS B3        A0 MEANS /S3  (SYNDROME BIT 3)
;         D2 MEANS B2        A1 MEANS /S2  (SYNDROME BIT 2)
;         D1 MEANS B1        A2 MEANS /S1  (SYNDROME BIT 1)
;         D0 MEANS B0        A3 MEANS /S0  (SYNDROME BIT 0)

;  B0-B7 ARE THE BITS OF THE DATA WORD.
;  THE SUBSTITUTIONS APPLY BELOW WITH THE EXCEPTION OF COMMENTS.


/A0 :=    D7* D6* D5             ;B7 :+: B6 :+: B5
     +   /D7*/D6* D5
     +   /D7* D6*/D5             ;   :+:
     +    D7*/D6*/D5
    :+:   D4*(/B0)               ;B4 :+: C3
     +   /D4*( B0)

/A1 :=    D7* D3* D2             ;B7 :+: B3 :+: B2
     +   /D7*/D3* D2
     +   /D7* D3*/D2             ;   :+:
     +    D7*/D3*/D2
    :+:   D1*(/B1)               ;B1 :+: C2
     +   /D1*( B1)

/A2 :=    D6* D5* D3             ;B6 :+: B5 :+: B3
     +   /D6*/D5* D3
     +   /D6* D5*/D3             ;   :+:
     +    D6*/D5*/D3
    :+:   D2* D0*( B2)           ;B2 :+: B0 :+: C1
     +   /D2*/D0*( B2)
     +   /D2* D0*(/B2)
     +    D2*/D0*(/B2)

/A3 :=    D6* D4* D3             ;B6 :+: B4 :+: B3
     +   /D6*/D4* D3
     +   /D6* D4*/D3             ;   :+:
     +    D6*/D4*/D3
    :+:   D1* D0*( B3)           ;B1 :+: B0 :+: C0
     +   /D1*/D0*( B3)
     +   /D1* D0*(/B3)
     +    D1*/D0*(/B3)


FUNCTION TABLE

SYNCLK /OC D7 D6 D5 D4 D3 D2 D1 D0 B0 B1 B2 B3 /A0 /A1 /A2 /A3

;CONTROL   --DATA-         ////
;SYN  /   DDDDDDDD  BBBB   AAAA
;CLK  OC  76543210  0123   0123   COMMENTS
-------------------------------------------
  C   L   HHHHHHHH  LLHH   LLLL   NO ERROR
  C   L   LHHHHHHH  LLHH   HHLL   D7 ERROR
  C   L   HLHHHHHH  LLHH   HLHH   D6 ERROR
  C   L   HHLHHHHH  LLHH   HLHL   D5 ERROR
  C   L   HHHLHHHH  LLHH   HLLH   D4 ERROR
  C   L   HHHHLHHH  LLHH   LHHH   D3 ERROR
  C   L   HHHHHLHH  LLHH   LHHL   D2 ERROR
  C   L   HHHHHHLH  LLHH   LHLH   D1 ERROR
  C   L   HHHHHHHL  LLHH   LLHH   D0 ERROR
  C   L   HHHHHHHH  HLHH   HLLL   B0 ERROR
  C   L   HHHHHHHH  LLHH   LLLL   NO ERROR
  C   L   HHHHHHHH  LLLH   LLHL   B2 ERROR
  C   L   HHHHHHHH  LLHL   LLLH   B1 ERROR
  C   L   LLLLLLLL  LLLL   LLLL   NO ERROR
  C   L   HLLLLLLL  LLLL   HHLL   D7 ERROR
  C   L   LHLLLLLL  LLLL   HLHH   D6 ERROR
  C   L   LLHLLLLL  LLLL   HLHL   D5 ERROR
  C   L   LLLHLLLL  LLLL   HLLH   D4 ERROR
  C   L   LLLLHLLL  LLLL   LHHH   D3 ERROR
  C   L   LLLLLHLL  LLLL   LHHL   D2 ERROR
  C   L   LLLLLLHL  LLLL   LHLH   D1 ERROR
  C   L   LLLLLLLH  LLLL   LLHH   D0 ERROR
  C   L   LLLLLLLL  HLLL   HLLL   B0 ERROR
  C   L   LLLLLLLL  LHLL   LHLL   B1 ERROR
  C   L   LLLLLLLL  LLHL   LLHL   B2 ERROR
  C   L   LLLLLLLL  LLLH   LLLH   B3 ERROR
-------------------------------------------


DESCRIPTION

THIS PAL GENERATES THE SYNDROME BITS FOR A 12 BIT HAMMING CODE WORD
AS A FUNCTION OF THE 8 DATA BITS AND THE 4 CHECK BITS TO POINT TO
ANY SINGLE BIT IN ERROR.