A method includes an integrated circuit with a memory. The memory operates
with an operating voltage. A value of a minimum operating voltage of the
memory is determined. The value of the minimum operating voltage is
stored in a non-volatile memory location that maybe a non-volatile
register. This minimum operating voltage information can then be used in
determining when an alternative power supply voltage may be switched to
the memory or ensuring that the minimum voltage is otherwise met. The
minimum voltage can be used only internal to the integrated circuit or
also provided externally to a user.