3.3V Uniform Sector

Standard and Dual Serial Flash

GD25D40C/20C

16

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

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

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

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.

Figure5. Read Data Bytes Sequence Diagram

7.6. 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, and each bit being latched-in on the rising edge of SCLK. Then the memory content,

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.

Figure6. Read Data Bytes at Higher Speed Sequence Diagram

Command

0

1

2

3

4

5

6

7

03H

CS#

SCLK

SI

SO

High-Z

8

9 10

28 29 30 31 32

MSB

3

2

1

0

34 35 36 37

33

23 22 21

7

6

5

4

3

2

1

0

38 39

24-bit address

MSB

Data Out1

Data Out2

Command

0

1

2

3

4

5

6

7

0BH

CS#

SCLK

SI

SO

High-Z

8

9 10

28 29 30 31

3

2

1

0

23 22 21

24-bit address

MSB

34 35 36 37

33

6

5

4

3

2

1

0

38 39

Data Out1

32

42 43 44 45

41

46 47

40

7

6

5

4

3

2

1

0

7

6

5

7

Data Out2

CS#

SCLK

SI

SO

MSB

Dummy Byte