PAL20X10 PAL DESIGN SPECIFICATION P7025 (SN54/74LS491) JOHN BIRKNER 04/01/81 10-BIT COUNTER MMI SUNNYVALE, CALIFORNIA CLK D0 D1 D2-7 D8 D9 /LD /CNT /UP SET /CIN GND /OC Q9 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 VCC /Q0 := /SET* LD*/D0 ;LOAD D0 + /SET*/LD*/Q0 ;HOLD (LSB) :+: /SET*/LD* CNT* CIN* UP ;INCREMENT + /SET*/LD* CNT* CIN*/UP ;DECREMENT /Q1 := /SET* LD*/D1 ;LOAD D1 + /SET*/LD*/Q1 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0 ;DECREMENT /Q2 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q2 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1 ;DECREMENT /Q3 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q3 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2 ;DECREMENT /Q4 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q4 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3 ;DECREMENT /Q5 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q5 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3* Q4 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3*/Q4 ;DECREMENT /Q6 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q6 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3* Q4* Q5 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3*/Q4*/Q5 ;DECREMENT /Q7 := /SET* LD*/D2-7 ;LOAD D2-7 + /SET*/LD*/Q7 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3* Q4* Q5* Q6 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3*/Q4*/Q5*/Q6 ;DECREMENT /Q8 := /SET* LD*/D8 ;LOAD D8 + /SET*/LD*/Q8 ;HOLD :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3* Q4* Q5* Q6* Q7 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3*/Q4*/Q5*/Q6*/Q7 ;DECREMENT /Q9 := /SET* LD*/D9 ;LOAD D9 + /SET*/LD*/Q9 ;HOLD (MSB) :+: /SET*/LD* CNT* CIN* UP* Q0* Q1* Q2* Q3* Q4* Q5* Q6* Q7* Q8 ;INCREMENT + /SET*/LD* CNT* CIN*/UP*/Q0*/Q1*/Q2*/Q3*/Q4*/Q5*/Q6*/Q7*/Q8 ;DECREMENT FUNCTION TABLE CLK /OC SET /LD /CNT /CIN /UP D9 D8 D2-7 D1 D0 Q9 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 ; / / ;C / S / C C / -DATA IN- -DATA OUT- ;L O E L N I U DD D DD QQQQQQQQQQ ;K C T D T N P 98 2-7 10 9876543210 COMMENT ------------------------------------------------------------------------------- C L H X X X X XX X XX HHHHHHHHHH SET (SET=H) C L L L X X X LL L LL LLLLLLLLLL CLEAR (D=L) C L L L X X X HH H HH HHHHHHHHHH SET (D=H) C L L H H X X LL L LL HHHHHHHHHH HOLD (/CNT=H) C L L L X X X LL L LL LLLLLLLLLL CLEAR (D=L) C L L H H X X XX X XX LLLLLLLLLL HOLD (/CNT=H) C L L H L H X XX X XX LLLLLLLLLL HOLD (/CIN=H) C L L H L L L XX X XX LLLLLLLLLH COUNT UP (NOTE 5 CNTRLS LOW NEAR GND) C L L H L L L XX X XX LLLLLLLLHL COUNT UP C L L H L L L XX X XX LLLLLLLLHH COUNT UP C L L H L L L XX X XX LLLLLLLHLL COUNT UP C L L H L L H XX X XX LLLLLLLLHH COUNT DOWN C L L H L L H XX X XX LLLLLLLLHL COUNT DOWN C L L H L L H XX X XX LLLLLLLLLH COUNT DOWN C L L H L L H XX X XX LLLLLLLLLL COUNT DOWN C L L H L L H XX X XX HHHHHHHHHH COUNT DOWN (ROLL UNDER) C L L H L L H XX X XX HHHHHHHHHL COUNT DOWN C L L H L L H XX X XX HHHHHHHHLH COUNT DOWN C L L H L L H XX X XX HHHHHHHHLL COUNT DOWN C L L H L L H XX X XX HHHHHHHLHH COUNT DOWN C L L H L L H XX X XX HHHHHHHLHL COUNT DOWN C L L H L L H XX X XX HHHHHHHLLH COUNT DOWN C L L H L L H XX X XX HHHHHHHLLL COUNT DOWN C L L L X X X LL L LL LLLLLLLLLL LOAD C L L H L L L XX X XX LLLLLLLLLH COUNT UP C L L H H X X XX X XX LLLLLLLLLH HOLD (/CNT=H) C L L H L L H XX X XX LLLLLLLLLL COUNT DOWN C L L L X X X LL H LL LLHHHHHHLL LOAD C L L H L L L XX X XX LLHHHHHHLH COUNT UP C L L H H X X XX X XX LLHHHHHHLH HOLD (/CNT=H) C L L H L L H XX X XX LLHHHHHHLL COUNT DOWN C L L L X X X HH L HH HHLLLLLLHH LOAD C L L H L L L XX X XX HHLLLLLHLL COUNT UP C L L H H X X XX X XX HHLLLLLHLL HOLD (/CNT=H) C L L H L L H XX X XX HHLLLLLLHH COUNT DOWN C L L L X X X LH L HL LHLLLLLLHL LOAD C L L H L L L XX X XX LHLLLLLLHH COUNT UP C L L H H X X XX X XX LHLLLLLLHH HOLD (/CNT=H) C L L H L L H XX X XX LHLLLLLLHL COUNT DOWN C L L L X X X HL H LH HLHHHHHHLH LOAD C L L H L L L XX X XX HLHHHHHHHL COUNT UP C L L H H X X XX X XX HLHHHHHHHL HOLD (/CNT=H) C L L H L L H XX X XX HLHHHHHHLH COUNT DOWN C L L L X X X HH H HH HHHHHHHHHH LOAD C L L H L L L HH H HH LLLLLLLLLL COUNT UP (ROLL OVER) X H X X X X X XX X XX ZZZZZZZZZZ TEST HI-Z ------------------------------------------------------------------------------- DESCRIPTION THE 10-BIT COUNTER CAN COUNT UP, COUNT DOWN, SET, AND LOAD 2 LSB'S (D0,D1), 2 MSB'S (D8,D9) AND 6 MIDDLE BITS (D2-7) HIGH OR LOW AS A GROUP. SET OVERRIDES LOAD (/LD), COUNT (/CNT), AND HOLD. LOAD OVERRIDES COUNT. COUNT IS CONDITIONAL ON CARRY IN (/CIN), OTHERWISE IT HOLDS. THESE OPERATIONS ARE EXERCISED IN THE FUNCTION TABLE AND SUMMARIZED IN THE OPERATIONS TABLE: /OC CLK SET /LD /CNT /CIN /UP D9-D0 Q9-Q0 OPERATION -------------------------------------------------------------------------- H X X X X X X X Z HI-Z L C H X X X X X H SET ALL HIGH L C L L X X X D D LOAD D L C L H H X X X Q HOLD (/CNT=H) L C L H L H X X Q HOLD (/CIN=H) L C L H L L L X Q PLUS 1 INCREMENT L C L H L L H X Q MINUS 1 DECREMENT --------------------------------------------------------------------------