AT45DB011_01 Datasheet, PDF (8/20 Pages) ATMEL Corporation – 1-megabit 2.7-volt Only Serial DataFlash

AC Waveforms
Two different timing diagrams are shown below. Waveform
1 shows the SCK signal being low when CS makes a high-
to-low transition, and Waveform 2 shows the SCK signal
being high when CS makes a high-to-low transition. Both
waveforms show valid timing diagrams. The setup and hold
times for the SI signal are referenced to the low-to-high
transition on the SCK signal.
Waveform 1 shows timing that is also compatible with SPI
Mode 0, and Waveform 2 shows timing that is compatible
with SPI Mode 3.
Waveform 1 – Inactive Clock Polarity Low
CS
tCSS
tWH tWL
tCSH
SCK
tV
HIGH IMPEDANCE
SO
tHO
VALID OUT
tSU
tH
SI
VALID IN
tCS
tDIS
HIGH IMPEDANCE
Waveform 2 – Inactive Clock Polarity High
CS
SCK
SO
SI
tCSS tWL tWH
tV
HIGH Z
tSU
tHO
VALID OUT
tH
VALID IN
tCSH
tCS
tDIS
HIGH IMPEDANCE
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AT45DB011