The present disclosure relates to methods of selectively placing a
reference column or reference row in a memory array. The method includes
measuring a resistance state resistance value for a plurality of variable
resistive memory cells within a memory array and mapping a location of
each measured variable resistive memory cell to form a map of the
resistance state resistance values for a plurality of variable resistive
memory cells within a memory array. Then a column or row is selected to
be a reference column or reference row based on the map of the resistance
state resistance value for a plurality of variable resistive memory cells
within a memory array, to minimize read operation errors, and forming a
variable resistive memory cell memory array.