426
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
Figure 25-10. Null Setup and Hold Values of NCS and NWE in Write Cycle
25.8.3.5
Null Pulse
Programming null pulse is not permitted. Pulse must be at least set to 1. A null value leads to
unpredictable behavior.
25.8.4
Write Mode
The WRITE_MODE parameter in the SMC_MODE register of the corresponding chip select indi-
cates which signal controls the write operation.
25.8.4.1
Write is Controlled by NWE (WRITE_MODE = 1):
shows the waveforms of a write operation with WRITE_MODE set to 1. The data is
put on the bus during the pulse and hold steps of the NWE signal. The internal data buffers are
switched to output mode after the NWE_SETUP time, and until the end of the write cycle,
regardless of the programmed waveform on NCS.
NCS
MCK
NWE
D[7:0]
NWE_PULSE
NCS_WR_PULSE
NWE_CYCLE
NWE_PULSE
NCS_WR_PULSE
NWE_CYCLE
NWE_PULSE
NCS_WR_PULSE
NWE_CYCLE
A[23:0]
Summary of Contents for SAM4S Series
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