A power up detection system for a memory device. Two rows of memory cells are mask programmed to include a word of data having an arbitrary size. The word in the second row is a single-bit shifted version of the word in the first row, such that each bit is shifted one bit position in a predetermined direction. The bits of the first word are read from the first row into slave latches of the register stages of a data register, and then shifted into the master latches of the next register stage of the data register. The bits of the second word are read from the second row into the slave latches of the register stages. Data comparison logic compares data stored in the master and slave latches of each register stage, and provides a signal indicating matching data between the first latches and the second latches, thereby indicating successful power up of the memory device.