GD25LQ40 datasheet(21/59 Pages) ELM

21 / 59 page

Rev.1.0

59 -

http://www.elm-tech.com

GD25LQ40xIGx 1.8V Uniform Sector Dual and Quad Serial Flash

Fast Read (0BH) in QPI mode

The Fast Read command is also supported in QPI mode. In QPI mode, the number of dummy clocks is

configured by the “Set Read Parameters (C0H)” command to accommodate a wide range application with

different needs for either maximum Fast Read frequency or minimum data access latency. Depending on the

Read Parameter Bits P[5:4] setting, the number of dummy clocks can be configured as either 4/6/8.

Figure 8a. Read Data Bytes at Higher Speed Sequence Diagram (QPI)

CS#

SCLK

IO0

IO1

IO2

IO3

Command

0BH

9 10

0 4

1 5

10 6

2 6

11 7

3 7

A23-16 A15-8 A7-0 Dummy*

11 12 13

IOs switch from

Input to output

Byte1 Byte2

*"Set Read Parameters" Command (C0H)

can set the number of dummy clocks

7.8. Dual Output Fast Read (3BH)

The Dual Output Fast Read command is followed by 3-byte address (A23-A0) and a dummy byte, each bit

being latched in during the rising edge of SCLK, then the memory contents are shifted out 2-bit per clock cycle

from SI and SO. The command sequence is shown in followed Figure9. The first byte addressed can be at any

location. The address is automatically incremented to the next higher address after each byte of data is shifted

out.

Figure 9. Dual Output Fast Read Sequence Diagram

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