An electronic device includes an enclosure body, a mounting apparatus, a securing apparatus, and a connector. In a low-luminance subfield, the every-cell initialization is performed, and a low-luminance subfield is subsequently located to the subfield for the every-cell initialization. The locations of specified memory cells are on a diagonal line on an array of memory cells in the memory device under test or on a reverse diagonal line which is perpendicular to the diagonal line.