Patent ID: 8780639

Claim:
A method of programming a first plurality of reference cells in a memory device having an array of non-volatile memory cells and a second plurality of comparators comprising: (i) programming one of said first plurality of reference cells; (ii) measuring the read signal of the programmed reference cell; (iii) comparing the read signal of the programmed reference cell measured to a first pre-determined value; (iv) continuing the programming of said first plurality of reference cells based upon said comparison; (v) programming a third plurality of non-volatile memory cells, wherein said third plurality is associated with one of said second plurality of comparators; (vi) reading said third plurality of non-volatile memory cells programmed using one of said second plurality of comparators; (vii) continuing the programming of the third plurality of non-volatile memory cells based upon said reading; (viii) measuring the read signals of the third plurality of non-volatile memory cells; (ix) calculating the median value of the read signals from the third plurality of non-volatile memory cells measured; (x) continuing the programming of said one of said first plurality of reference cells; (xi) measuring the read signal of the programmed reference cell; (xii) comparing the read signal of the programmed reference cell measured to a second pre-determined value; and (xiii) continuing the programming of said first plurality of reference cells based upon said comparison.