GD25Q21 datasheet(18/49 Pages) ELM

18 / 49 page

Rev.1.1

49 -

http://www.elm-tech.com

GD25Q21BxIGx Uniform Sector Dual and Quad Serial Flash

7.7. Read Data Bytes (READ) (03H)

The Read Data Bytes (READ) command is followed by a 3-byte address (A23-A0), each bit being latched-in

during the rising edge of SCLK. Then the memory content, at that address, is shifted out on SO, each bit being

shifted out, at a Max frequency fR, during the falling edge of SCLK. 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. The whole memory can, therefore, be read with a single Read Data Bytes (READ) command. Any Read

Data Bytes (READ) command, while an Erase, Program or Write cycle is in progress, is rejected without having

any effects on the cycle that is in progress.

Figure 8. Read Data Bytes Sequence Diagram

Command

0 1 2 3 4 5 6 7

03H

CS#

SCLK

High-Z

8 9 10

28 29 30 31 32

MSB

3 2 1 0

34 35 36 37

23 22 21

7 6 5 4 3 2 1 0

38 39

24-bit address

MSB

Data Out1

Data Out2

7.8. Read Data Bytes at Higher Speed (Fast Read) (0BH)

The Read Data Bytes at Higher Speed (Fast Read) command is for quickly reading data out. It is followed by

a 3-byte address (A23-A0) and a dummy byte, each bit being latched-in during the rising edge of SCLK. Then

the memory content, at that address, is shifted out on SO, each bit being shifted out, at a Max frequency fC,

during the falling edge of SCLK. 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. Read Data Bytes at Higher Speed Sequence Diagram

GD25Q21 Datasheet(PDF) 18 Page - ELM Electronics