Mixed storage of data fields

A circuit arrangement comprising:

• an array of non-volatile memory cells arranged in a plurality of rows and a plurality of columns;
• a volatile storage circuit configured to provide addressable units of storage;
• and
• a control circuit coupled to the array of non-volatile memory cells and to the volatile storage circuit, wherein the control circuit is configured to read first type data and second type data from one or more rows of the plurality of rows and the plurality of columns of the array of non-volatile memory cells, and store the first type data and second type read from each row in one or more addressable units of storage of the volatile storage circuit;
• and
• a security circuit coupled to the volatile storage circuit, the security circuit configured to:
• read first data from the one or more of the addressable units of the volatile storage circuit,
• select from the first data, the second type data that includes one or more bits of each of the one or more of the addressable units,
• perform an integrity check on the second type data selected from the first data, and
• generate an alert signal that indicates a security violation in response to failure of the integrity check.