Atmel SAM4S Series, Preliminary Data Sheet

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11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
Figure 25-8. READ_MODE = 0: Data is sampled by SMC before the rising edge of NCS
25.8.3 Write Waveforms
The write protocol is similar to the read protocol. It is depicted in Figure 25-9 . The write cycle
starts with the address setting on the memory address bus.
25.8.3.1 NWE Waveforms
The NWE signal is characterized by a setup timing, a pulse width and a hold timing.
1. NWE_SETUP: the NWE setup time is defined as the setup of address and data before
the NWE falling edge;
2. NWE_PULSE: The NWE pulse length is the time between NWE falling edge and NWE
rising edge;
3. NWE_HOLD: The NWE hold time is defined as the hold time of address and data after
the NWE rising edge.
25.8.3.2 NCS Waveforms
The NCS signal waveforms in write operation are not the same that those applied in read opera-
tions, but are separately defined:
1. NCS_WR_SETUP: the NCS setup time is defined as the setup time of address before
the NCS falling edge.
2. NCS_WR_PULSE: the NCS pulse length is the time between NCS falling edge and
NCS rising edge;
3. NCS_WR_HOLD: the NCS hold time is defined as the hold time of address after the
NCS rising edge.
Data Sampling
t
PACC
MCK
D[7:0]
A[23:0]
NCS
NRD