39.7.13.2 Frozen Mode

When the external device asserts the NWAIT signal (active low), and after internal synchronization of this signal, the EBI state is frozen, i.e., SMC internal counters are frozen, and all control signals remain unchanged. When the resynchronized NWAIT signal is deasserted, the EBI completes the access, resuming the access from the point where it was stopped. This mode must be selected when the external device uses the NWAIT signal to delay the access and to freeze the EBI.

The assertion of the NWAIT signal outside the expected period is ignored as illustrated in the following figure.