W25X05CLZPIG datasheet(20/51 Pages) WINBOND

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W25X05CL/10CL/20CL

Publication Release Date: March 23, 2012

- 20 -

Revision B

8.2.10 Fast Read Dual Output (3Bh)

The Fast Read Dual Output (3Bh) instruction is similar to the standard Fast Read (0Bh) instruction

except that data is output on two pins, IO0 and IO1. This allows data to be transferred from the

W25X05CL/10CL/20CL at twice the rate of standard SPI devices. The Fast Read Dual Output

instruction is ideal for quickly downloading code from Flash to RAM upon power-up or for applications

that cache code-segments to RAM for execution.

Similar to the Fast Read instruction, the Fast Read Dual Output instruction can operate 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 11. The dummy clocks allow the device's

internal circuits additional time for setting up the initial address. The input data during the dummy

clocks is “don’t care”. However, the IO

0 pin should be high-impedance prior to the falling edge of the

first data out clock.

Figure 11. Fast Read Dual Output Instruction Sequence Diagram

/CS

CLK

(IO

Mode 0

Mode 3

Instruction (3Bh)

High Impedance

24-Bit Address

/CS

CLK

(IO

Dummy Clocks

High Impedance

0 switches from

Input to Output

Data Out 1

* Data Out 2

* Data Out 3

* Data Out 4

= MSB

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