Valid addresses range is from 0000h to 7DFFh
 and from 8000h to 807Fh.
 The address range from 7DFEh to 7DFFh are
 reserved for 'Write/Erase Lock Byte'
 and 'Read Lock Byte'.
 The address range from 7E00h to 7FFFh are
 reserved for factory use.
 The address range from 8000h to 807Fh are
 locked only if all blocks are locked.