PAL16R8 PAL DESIGN SPECIFICATION P7062 (PMSI001) BIRKNER/COLI 04/07/82 3-TO-8 DEMULTIPLEXER WITH CONTROL STORAGE MMI SUNNYVALE, CALIFORNIA CLK /CLR /PR A B C /LD POL TOG GND /OC Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 VCC /Q0 := CLR ;CLEAR Q0 + /PR* LD*/POL*/C*/B*/A ;LOAD COMPLEMENT (DECODE 000) + /PR* LD* POL* A ;LOAD TRUE + /PR* LD* POL* B ;LOAD TRUE + /PR* LD* POL* C ;LOAD TRUE + /PR*/LD*/TOG*/Q0 ;HOLD + /PR*/LD* TOG* Q0 ;TOGGLE POLARITY /Q1 := CLR ;CLEAR Q1 + /PR* LD*/POL*/C*/B* A ;LOAD COMPLEMENT (DECODE 001) + /PR* LD* POL* /A ;LOAD TRUE + /PR* LD* POL* B ;LOAD TRUE + /PR* LD* POL* C ;LOAD TRUE + /PR*/LD*/TOG*/Q1 ;HOLD + /PR*/LD* TOG* Q1 ;TOGGLE POLARITY /Q2 := CLR ;CLEAR Q2 + /PR* LD*/POL*/C* B*/A ;LOAD COMPLEMENT (DECODE 010) + /PR* LD* POL* A ;LOAD TRUE + /PR* LD* POL* /B ;LOAD TRUE + /PR* LD* POL* C ;LOAD TRUE + /PR*/LD*/TOG*/Q2 ;HOLD + /PR*/LD* TOG* Q2 ;TOGGLE POLARITY /Q3 := CLR ;CLEAR Q3 + /PR* LD*/POL*/C* B* A ;LOAD COMPLEMENT (DECODE 011) + /PR* LD* POL* /A ;LOAD TRUE + /PR* LD* POL* /B ;LOAD TRUE + /PR* LD* POL* C ;LOAD TRUE + /PR*/LD*/TOG*/Q3 ;HOLD + /PR*/LD* TOG* Q3 ;TOGGLE POLARITY /Q4 := CLR ;CLEAR Q4 + /PR* LD*/POL* C*/B*/A ;LOAD COMPLEMENT (DECODE 100) + /PR* LD* POL* A ;LOAD TRUE + /PR* LD* POL* B ;LOAD TRUE + /PR* LD* POL*/C ;LOAD TRUE + /PR*/LD*/TOG*/Q4 ;HOLD + /PR*/LD* TOG* Q4 ;TOGGLE POLARITY /Q5 := CLR ;CLEAR Q5 + /PR* LD*/POL* C*/B* A ;LOAD COMPLEMENT (DECODE 101) + /PR* LD* POL* /A ;LOAD TRUE + /PR* LD* POL* B ;LOAD TRUE + /PR* LD* POL*/C ;LOAD TRUE + /PR*/LD*/TOG*/Q5 ;HOLD + /PR*/LD* TOG* Q5 ;TOGGLE POLARITY /Q6 := CLR ;CLEAR Q6 + /PR* LD*/POL* C* B*/A ;LOAD COMPLEMENT (DECODE 110) + /PR* LD* POL* A ;LOAD TRUE + /PR* LD* POL* /B ;LOAD TRUE + /PR* LD* POL*/C ;LOAD TRUE + /PR*/LD*/TOG*/Q6 ;HOLD + /PR*/LD* TOG* Q6 ;TOGGLE POLARITY /Q7 := CLR ;CLEAR Q7 + /PR* LD*/POL* C* B* A ;LOAD COMPLEMENT (DECODE 111) + /PR* LD* POL* /A ;LOAD TRUE + /PR* LD* POL* /B ;LOAD TRUE + /PR* LD* POL*/C ;LOAD TRUE + /PR*/LD*/TOG*/Q7 ;HOLD + /PR*/LD* TOG* Q7 ;TOGGLE POLARITY FUNCTION TABLE /OC CLK /CLR /PR /LD POL TOG C B A Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 ;CONTROL FUNCTIONS POLARITY INPUT OUTPUT ;/OC CLK /CLR /PR /LD POL TOG CBA Q7----Q0 COMMENTS ------------------------------------------------------------------------------- L C L L L H L XXX LLLLLLLL CLEAR (OVERRIDES /PR) L C H L L H L XXX HHHHHHHH PRESET (OVERRIDES /LD) L C H H L H X LLL LLLLLLLH LOAD 0 (TRUE INPUT) L C H H L H X LLH LLLLLLHL LOAD 1 (TRUE INPUT) L C H H L H X LHL LLLLLHLL LOAD 2 (TRUE INPUT) L C H H L H X LHH LLLLHLLL LOAD 3 (TRUE INPUT) L C H H L H X HLL LLLHLLLL LOAD 4 (TRUE INPUT) L C H H L H X HLH LLHLLLLL LOAD 5 (TRUE INPUT) L C H H L H X HHL LHLLLLLL LOAD 6 (TRUE INPUT) L C H H L H X HHH HLLLLLLL LOAD 7 (TRUE INPUT) L C H H H X L XXX HLLLLLLL HOLD 7 (TRUE POLARITY) L C H H H X H XXX LHHHHHHH HOLD (TOGGLE POLARITY) L C H H H X H XXX HLLLLLLL HOLD (TOGGLE POLARITY) L C H H L L X LLL HHHHHHHL LOAD 0 (COMP INPUT) L C H H L L X LLH HHHHHHLH LOAD 1 (COMP INPUT) L C H H L L X LHL HHHHHLHH LOAD 2 (COMP INPUT) L C H H L L X LHH HHHHLHHH LOAD 3 (COMP INPUT) L C H H L L X HLL HHHLHHHH LOAD 4 (COMP INPUT) L C H H L L X HLH HHLHHHHH LOAD 5 (COMP INPUT) L C H H L L X HHL HLHHHHHH LOAD 6 (COMP INPUT) L C H H L L X HHH LHHHHHHH LOAD 7 (COMP INPUT) L C H H H X L XXX LHHHHHHH HOLD 7 (TRUE POLARITY) L C H H H X H XXX HLLLLLLL HOLD (TOGGLE POLARITY) L C H H H X H XXX LHHHHHHH HOLD (TOGGLE POLARITY) H X X X X X X XXX ZZZZZZZZ TEST HI-Z ------------------------------------------------------------------------------- DESCRIPTION THE 3-TO-8 DEMULTIPLEXER WITH CONTROL STORAGE PROVIDES A CONVENTIONAL 8-BIT DEMUX FUNCTION COMBINED WITH CONTROL STORAGE FUNCTIONS: LOAD TRUE, LOAD COMPLE- MENT, HOLD, TOGGLE POLARITY, CLEAR, AND PRESET. FIVE INPUTS (/LD, /CLR, /PR, POL, TOG) SELECT ONE OF SIX OPERATIONS WHICH OCCUR SYNCHRONOUSLY WITH THE RISING EDGE OF THE CLOCK (CLK). THE LOAD TRUE OPERATION LOADS THE DECODED BINARY INPUTS (A,B,C) INTO THE OUTPUT REGISTER (Q7-Q0) WHEN POLARITY IS TRUE (POL=H). THE COMPLEMENT OF THE BINARY INPUTS IS DECODED AND LOADED INTO THE OUTPUT REGISTER WHEN POLARITY IS FALSE (POL=L). THE HOLD OPERATION HOLDS THE PREVIOUS VALUE IN THE REGISTER WHEN TOGGLE IS FALSE (TOG=L) REGARDLESS OF CLOCK TRANSITIONS. THE TOGGLE POLARITY OPERATION TOGGLES THE POLARITY OF THE DATA IN THE OUTPUT REGISTER WHEN TOGGLE IS TRUE (TOG=H). THE CLEAR (/CLR) OPERATION RESETS THE OUTPUT REGISTER TO ALL LOWS. THE PRESET (/PR) OPERATION PRESETS THE OUTPUT REGISTER TO ALL HIGHS. NOTE THAT CLEAR OVERRIDES PRESET, PRESET OVERRIDES LOAD, AND LOAD OVERRIDES HOLD. THE POLARITY OF "POL" MAY BE CHANGED IN THE LOGIC EQUATIONS TO SUIT SPECIFIC APPLICATIONS SO THAT CERTAIN OUTPUT POLARITIES ARE ASSERTIVE HIGH WHILE OTHERS ARE ASSERTIVE LOW. THESE OPERATIONS ARE EXERCISED IN THE FUNCTION TABLE AND SUMMARIZED IN THE OPERATIONS TABLE: CONTROL FUNCTIONS POLARITY INPUTS OUTPUTS /OC CLK /CLR /PR /LD POL TOG ABC Q7-Q0 OPERATION ------------------------------------------------------------------------ H X X X X X X X Z HI-Z L C L X X X X X L CLEAR L C H L X X X X H PRESET L C H H L H X I MUX LOAD TRUE L C H H L L X I /MUX LOAD COMP L C H H H X L X Q HOLD L C H H H X H X /Q TOGGLE POLARITY ------------------------------------------------------------------------