bcd7.abl

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module  BCD7
title 'seven segment display decoder    1 Aug 1990
Walter Bright  Data I/O Corp  Redmond WA'
"          a
"         ---       BCD-to-seven-segment decoder similar to the 7449
"       f| g |b
"         ---           segment identification
"       e| d |c
"         ---
        bcd7 device  'P16V8R';

        D3,D2,D1,D0     pin 5,4,3,2;
        a,b,c,d,e,f,g   pin 19,18,17,16,15,14,13 istype 'com';

        bcd     = [D3,D2,D1,D0];
        led     = [a,b,c,d,e,f,g];

        ON,OFF  = 0,1;                  " for common anode LEDs 
        L,H,X,Z = 0,1,.X.,.Z.;
@dcset
truth_table (bcd -> [ a ,  b ,  c ,  d ,  e ,  f ,  g ])
              ^b0000  -> [ ON,  ON,  ON,  ON,  ON,  ON, OFF];
              ^b0001  -> [OFF,  ON,  ON, OFF, OFF, OFF, OFF];
              ^b0010  -> [ ON,  ON, OFF,  ON,  ON, OFF,  ON];
              ^b0011  -> [ ON,  ON,  ON,  ON, OFF, OFF,  ON];
              ^b0100  -> [OFF,  ON,  ON, OFF, OFF,  ON,  ON];
              ^b0101  -> [ ON, OFF,  ON,  ON, OFF,  ON,  ON];
              ^b0110  -> [ ON, OFF,  ON,  ON,  ON,  ON,  ON];
              ^b0111  -> [ ON,  ON,  ON, OFF, OFF, OFF, OFF];
              ^b1000  -> [ ON,  ON,  ON,  ON,  ON,  ON,  ON];
              ^b1001  -> [ ON,  ON,  ON,  ON, OFF,  ON,  ON];
              ^b1010  -> [ ON,  ON,  ON,  OFF, ON,  ON,  ON];
              ^b1011  -> [ OFF,  OFF,  ON,  ON, ON,  ON, ON];
              ^b1100  -> [ ON,  OFF,  OFF,  ON, ON, ON, OFF];
              ^b1101  -> [ OFF,  ON,  ON,  ON, ON,  OFF, ON];
              ^b1110  -> [ ON,  OFF,  OFF,  ON, ON,  ON, ON];
              ^b1111  -> [ ON,  OFF,  OFF,  OFF, ON, ON, ON];

test_vectors (bcd -> [ a ,  b ,  c ,  d ,  e ,  f ,  g ])
              ^b0000  -> [ ON,  ON,  ON,  ON,  ON,  ON, OFF];
              ^b0001  -> [OFF,  ON,  ON, OFF, OFF, OFF, OFF];
              ^b0010  -> [ ON,  ON, OFF,  ON,  ON, OFF,  ON];
              ^b0011  -> [ ON,  ON,  ON,  ON, OFF, OFF,  ON];
              ^b0100  -> [OFF,  ON,  ON, OFF, OFF,  ON,  ON];
              ^b0101  -> [ ON, OFF,  ON,  ON, OFF,  ON,  ON];
              ^b0110  -> [ ON, OFF,  ON,  ON,  ON,  ON,  ON];
              ^b0111  -> [ ON,  ON,  ON, OFF, OFF, OFF, OFF];
              ^b1000  -> [ ON,  ON,  ON,  ON,  ON,  ON,  ON];
              ^b1001  -> [ ON,  ON,  ON,  ON, OFF,  ON,  ON];
              ^b1010  -> [ ON,  ON,  ON,  OFF, ON,  ON,  ON];
              ^b1011  -> [ OFF,  OFF,  ON,  ON, ON,  ON, ON];
              ^b1100  -> [ ON,  OFF,  OFF,  ON, ON, ON, OFF];
              ^b1101  -> [ OFF,  ON,  ON,  ON, ON,  OFF, ON];
              ^b1110  -> [ ON,  OFF,  OFF,  ON, ON,  ON, ON];
              ^b1111  -> [ ON,  OFF,  OFF,  OFF, ON, ON, ON];
end