41-02

Found on...

• Super Off Road

Equations

/**********************************************************************/
/*Super Off Road U54                                                  */
/*decoder for various RAM/ROM CS lines, PA15, and /EXP                */
/**********************************************************************/

/** Inputs **/

PIN     1   = i1;
PIN     2   = i2;
PIN     3   = i3;
PIN     4   = i4;
PIN     5   = i5;
PIN     6   = i6;
PIN     7   = i7;
PIN     8   = i8;
PIN     9   = i9;

/** Outputs **/

PIN    12   = o12;
PIN    13   = o13;
PIN    14   = o14;
PIN    15   = o15;
PIN    16   = o16;
PIN    17   = o17;
PIN    18   = o18;
PIN    19   = o19;

/** Logic Equations **/

!o12 = !i2 & !i3 & i4 & i5 & i6 #
       i2 & !i3 #
       !i1 & !i3;

!o13 = i1 & !i2 & i4 & !i5 & !i6 & i8 & i9 #
       i1 & !i2 & !i4 & !i5 & i6 & i8 & i9 #
       i1 & !i2 & !i4 & i5 & i8 & i9;

!o14 = i1 & !i2 & i4 & !i5 & !i6 & !i8 & i9 #
       i1 & !i2 & !i4 & !i5 & i6 & !i8 & i9 #
       i1 & !i2 & !i4 & i5 & !i8 & i9;

!o15 = i1 & !i2 & i4 & i5 & !i6 & i7 & !i8 & !i9 #
       i1 & !i2 & i4 & !i5 & i6 & i7 & !i8 & !i9;

!o16 = i1 & !i2 & i4 & !i5 & i6;

!o17 = i1 & !i2 & i4 & !i5 & !i6 & i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & i6 & i8 & !i9 #
       i1 & !i2 & !i4 & i5 & i8 & !i9;

!o18 = i1 & !i2 & !i4 & o13 & o14 & o15 & o17 #
       i1 & !i2 & !i5 & o13 & o14 & o15 & o17 #
       i1 & !i2 & !i6 & o13 & o14 & o15 & o17;

!o19 = i1 & !i2 & !i5 & !i6 & !i7 & !i8 & i9 #
       i1 & !i2 & !i5 & !i6 & !i7 & i8 #
       i1 & !i2 & !i4 & !i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & i6 & !i7 #
       i1 & !i2 & !i4 & i5 & !i7 #
       i1 & !i2 & !i4 & !i5 & !i6;


/* reverse engineered o18 had too many product terms by itself for 16V8
need to use feedback to be input of any /CS and not any of the other /CS output lines active

Original o18:

!o18 = i1 & !i2 & !i5 & i6 & !i7 & !i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & i6 & !i8 & !i9 #
       i1 & !i2 & i4 & i5 & !i6 & i9 #
       i1 & !i2 & i4 & i5 & !i6 & i8 #
       i1 & !i2 & !i4 & i5 & !i8 & !i9 #
       i1 & !i2 & i4 & !i5 & i6 & i9 #
       i1 & !i2 & i4 & !i5 & i6 & i8 #
       i1 & !i2 & !i6 & !i7 & !i8 & !i9 #
       i1 & !i2 & !i5 & !i6 & !i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & !i6;


Combining all chip selects together:

!cs =  i1 & !i2 & !i5 & i6 & !i7 & !i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & i6 & !i8 & !i9 #
       i1 & !i2 & i4 & i5 & !i6 & i9 #
       i1 & !i2 & i4 & i5 & !i6 & i8 #
       i1 & !i2 & !i4 & i5 & !i8 & !i9 #
       i1 & !i2 & i4 & !i5 & i6 & i9 #
       i1 & !i2 & i4 & !i5 & i6 & i8 #
       i1 & !i2 & !i6 & !i7 & !i8 & !i9 #
       i1 & !i2 & !i5 & !i6 & !i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & !i6 #

       i1 & !i2 & i4 & !i5 & !i6 & i8 & !i9 #
       i1 & !i2 & !i4 & !i5 & i6 & i8 & !i9 #
       i1 & !i2 & !i4 & i5 & i8 & !i9 #

       i1 & !i2 & i4 & i5 & !i6 & i7 & !i8 & !i9 #
       i1 & !i2 & i4 & !i5 & i6 & i7 & !i8 & !i9 #

       i1 & !i2 & i4 & !i5 & !i6 & !i8 & i9 #
       i1 & !i2 & !i4 & !i5 & i6 & !i8 & i9 #
       i1 & !i2 & !i4 & i5 & !i8 & i9 #

       i1 & !i2 & i4 & !i5 & !i6 & i8 & i9 #
       i1 & !i2 & !i4 & !i5 & i6 & i8 & i9 #
       i1 & !i2 & !i4 & i5 & i8 & i9;
       
       
Checking minimized output equation in .doc file shows /CS is:

!cs =  i1 & !i2 & !i4 #
       i1 & !i2 & !i5 #
       i1 & !i2 & !i6;
*/