SAM3SD8B Atmel Corporation, SAM3SD8B Datasheet - Page 400

• Manufacturer Part Number: SAM3SD8B
• Manufacturer: Atmel Corporation

23.12.2
Figure 23-23. Write Access with NWAIT Assertion in Frozen Mode (EXNW_MODE = 10)
400
400
internally synchronized
NWAIT signal
SAM3S8/SD8
SAM3S8/SD8
Frozen Mode
A [23:0]
D[7:0]
NWAIT
NWE
MCK
NCS
6
When the external device asserts the NWAIT signal (active low), and after internal synchroniza-
tion of this signal, the SMC state is frozen, i.e., SMC internal counters are frozen, and all control
signals remain unchanged. When the resynchronized NWAIT signal is deasserted, the SMC
completes the access, resuming the access from the point where it was stopped. See
23. This mode must be selected when the external device uses the NWAIT signal to delay the
access and to freeze the SMC.
The assertion of the NWAIT signal outside the expected period is ignored as illustrated in
23-24.
4
5
4
3
3
2
1
2
EXNW_MODE = 10 (Frozen)
WRITE_MODE = 1 (NWE_controlled)
NWE_PULSE = 5
NCS_WR_PULSE = 7
Write cycle
1
2
FROZEN STATE
1
2
1
2
1
0
0
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
Figure 23-
Figure