US Patent 7583546 Apparatus and method of operating an integrated circuit

The method of operating an integrated circuit including the step of writing to a memory cell, which can assume a first and a second logical state and wherein a change from the second logical state to the first logical state lasts longer than a change from the first logical state to the second logical state, includes reading the logical state of the memory cell, changing, depending on the logical state of the memory cell read, the logical state to the first logical state or retaining the same in the first logical state and, depending on the logical state to be written, changing the logical state to the second logical state or retaining the same in the first logical state.