Figure 6. State diagram for memory cells (i,j) under ↑ inverse coupling fault cfinv_ij

2.3.2.  Idempotent coupling faults

In a 2-indempotent coupling fault cfid_ij say, involving cells i and j , a transition (0 to1 or 1 to 0) in memory cell j sets the value in memory cell i to be 0 or 1. The four possible 2- idempotent coupling faults involving cells i ,j (denoted as cfid_ij ) are

•  Rising-0: (0 to1 change in cell j sets the content of cell i to be 0)

•  Rising-1: (0 to1 change in cell j sets the content of cell i to be 1)

•  Falling-0: (1 to 0 change in cell j sets the content of cell i to be 0)

•  Falling-1: (1 to 0 change in cell j sets the content of cell i to be 1)

Figure 7 shows the state machine for two cells i and j under rising-1 idempotent coupling fault cfid_ij. If we compare Figure 5 and Figure 7 we note that under normal condition if we write 1 to cell j (from state S00) we go to state S01, however, under rising-1 cfid_ijwe go to state S11. This situation is similar to ↑inverse coupling fault (Figure 6). However, unlike ↑ inverse coupling fault (Figure 6), in rising-1 idempotent coupling fault we do not have a faulty transition from S10 to S01.