EN25Q40A Datasheet, PDF (24/64 Pages) Eon Silicon Solution Inc. – 4 Megabit Serial Flash Memory with 4Kbyte Uniform Sector

EN25Q40A
Figure 13.1 Fast Read Instruction Sequence in QPI Mode
Dual Output Fast Read (3Bh)
The Dual Output Fast Read (3Bh) is similar to the standard Fast Read (0Bh) instruction except that
data is output on two pins, DQ₀ and DQ₁, instead of just DQ₀. This allows data to be transferred from
the EN25Q40A at twice the rate of standard SPI devices. The Dual Output Fast Read instruction is
ideal for quickly downloading code from to RAM upon power-up or for applications that cache code-
segments to RAM for execution.
Similar to the Fast Read instruction, the Dual Output Fast Read instruction can operation at the highest
possible frequency of FR (see AC Electrical Characteristics). This is accomplished by adding eight
“dummy clocks after the 24-bit address as shown in Figure 14. The dummy clocks allow the device’s
internal circuits additional time for setting up the initial address. The input data during the dummy clock
is “don’t care”. However, the DI pin should be high-impedance prior to the falling edge of the first data
out clock.
This Data Sheet may be revised by subsequent versions
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or modifications due to changes in technical specifications.
©2014 Eon Silicon Solution, Inc.,
Rev. F, Issue Date: 2014/04/02
www.eonssi.com