US Patent 9123434 Semiconductor device verifying signal supplied from outside

A method for accessing a semiconductor device having a memory array, includes receiving a chip select signal, receiving a command signal and an address signal, receiving a verification signal, calculating an error signal based on the address signal, the command signal, and the verification signal, generating an internal chip select signal based on the received chip select signal if the error signal indicates no error, and generating an external alert signal if the error signal indicates an error.