Memory devices including a controller for access of an array of memory cells that is configured to accept a sequence of commands to cause the memory device to read a first set of data from the array of memory cells into a first register, load the first set of data into a first portion of a second register, write a set of test data to a second portion of the second register during a reading of a second set of data from the array of memory cells to the first register, read the set of test data from the second portion of the second register during the reading of the second set of data, and output the set of test data from the memory device during the reading of the second set of data.