LE25FS406

No.A1577-6/22

Description of Commands and Their Operations

A detailed description of the functions and operations corresponding to each command is presented below.

1. Standard SPI read

There are two read commands, the standard SPI read command and High-speed read command.

1-1. Read command

Consisting of the first through fourth bus cycles, the 4 bus cycle read command inputs the 24-bit addresses following

(03h). The data is output from SO on the falling clock edge of fourth bus cycle bit 0 as a reference. "Figure 4-a Read"

shows the timing waveforms.

Figure 5-a 4 Bus Read

1-2. High-speed Read command

Consisting of the first through fifth bus cycles, the High-speed read command inputs the 24-bit addresses and 8 dummy

bits following (0Bh). The data is output from SO using the falling clock edge of fifth bus cycle bit 0 as a reference.

"Figure 4-b High-speed Read" shows the timing waveforms.

Figure 4-b High-speed Read

When SCK is input continuously after the read command has been input and the data in the designated addresses has

been output, the address is automatically incremented inside the device while SCK is being input, and the corresponding

data is output in sequence. If the SCK input is continued after the internal address arrives at the highest address

(7FFFFh), the internal address returns to the lowest address (00000h), and data output is continued. By setting the logic

level of CS to high, the device is deselected, and the read cycle ends. While the device is deselected, the output pin SO

is in a high-impedance state.

N+2

N+1

N

CS

High Impedance

DATA

DATA

DATA

SCK

SO

SI

03h

Add.

Add.

Add.

15

MSB

MSB

MSB

0

1

2

3

4

5

6

7

8

23

16

24

31

39

47

8CLK

Mode0

Mode3

32

40

N+2

N+1

N

CS

High Impedance

DATA

DATA

DATA

SCK

SO

SI

0Bh

Add.

Add.

Add.

X

15

MSB

MSB

MSB

0

1

2

3

4

5

6

7

8

23

16

24

31 32

39 40

47 48

55

Mode3

Mode0

8CLK

MSB