LE25FU206

No.A1191-6/21

Description of Commands and Their Operations

"Table 2 Command Settings" provides a list and overview of the commands. A detailed description of the functions and

operations corresponding to each command is presented below.

1. Read

There are two read commands, the 4 bus cycle read command and 5 bus cycle read command. Consisting of the first

through fourth bus cycles, the 4 bus cycle read command inputs the 24-bit addresses following (03h), and the data in the

designated addresses is output synchronized to SCK. The data is output from SO on the falling clock edge of fourth bus

cycle bit 0 as a reference. "Figure 5-a 4 Bus Read" shows the timing waveforms.

Consisting of the first through fifth bus cycles, the 5 bus cycle 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 5-b 5 Bus Read" shows the timing waveforms. The only difference between these two commands is whether the

dummy bits in the fifth bus cycle are input.

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

(3FFFFh), 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.

Figure 5-a 4 Bus Read

Figure 5-b 5 Bus Read

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