3.5 Blank Check

The term “Blank Check” implies verifying that the device has been successfully erased and has no programmed memory locations. A blank or erased memory location is always read as ‘1’.

The Device ID registers (0xFF0000:0xFF0002) can be ignored by the Blank Check since this region stores device information that cannot be erased. Additionally, all unimplemented memory space and Calibration registers should be ignored by the Blank Check.

The QBLANK command is used for the Blank Check. It determines if the code memory is erased by testing these memory regions. A ‘BLANK’ or ‘NOT BLANK’ response is returned. If it is determined that the device is not blank, it must be erased before attempting to program the chip.