Ready Mode

In Ready mode (SMC_MODE.EXNW_MODE = 11), the SMC behaves differently. Normally, the SMC begins the access by down counting the setup and pulse counters of the read/write controlling signal. In the last cycle of the pulse phase, the resynchronized NWAIT signal is examined.

If asserted, the SMC suspends the access as shown in Figure 1 and Figure 2. After deassertion, the access is completed: the hold step of the access is performed.

This mode must be selected when the external device uses deassertion of the NWAIT signal to indicate its ability to complete the read or write operation.

If the NWAIT signal is deasserted before the end of the pulse, or asserted after the end of the pulse of the controlling read/write signal, it has no impact on the access length as shown in Figure 2.

Figure 1. NWAIT Assertion in Write Access: Ready Mode (SMC_MODE.EXNW_MODE = 11)
Figure 2. NWAIT Assertion in Read Access: Ready Mode (SMC_MODE.EXNW_MODE = 11)