LE25S20FD

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7

2. Status Registers

The status registers hold the operating and setting statuses inside the device, and this information can be read

(status register read) and the protect information can be rewritten (status register write). There are 8 bits in total,

and "Table 4 Status registers" gives the significance of each bit.

Table 4 Status Registers

Bit

Name

Logic

Function

Power-on Time Information

Bit0

RDY

0

Ready

0

1

Erase/Program

Bit1

WEN

0

Write disabled

0

1

Write enabled

Bit2

BP0

0

Block protect information

Protecting area switch

Nonvolatile information

1

Bit3

BP1

0

Nonvolatile information

1

Bit4

BP2

0

Nonvolatile information

1

Bit5

TB

0

Block protect

Upper side/Lower side switch

Nonvolatile information

1

Bit6

Reserved bits

0

Bit7

SRWP

0

Status register write enabled

Nonvolatile information

1

Status register write disabled

2-1. Status register read

The contents of the status registers can be read using the status register read command. This command can be

executed even during the following operations.

 Small sector erase, sector erase, chip erase

 Page program

 Status register write

"Figure 5 Status Register Read" shows the timing waveforms of status register read. Consisting only of the first

bus cycle, the status register command outputs the contents of the status registers synchronized to the falling edge

of the clock (SCK) with which the eighth bit of (05h) has been input. In terms of the output sequence, SRWP (bit

7) is the first to be output, and each time one clock is input, all the other bits up to RDY (bit 0) are output in

sequence, synchronized to the falling clock edge. If the clock input is continued after RDY (bit 0) has been output,

the data is output by returning to the bit (SRWP) that was first output, after which the output is repeated for as long

as the clock input is continued. The data can be read by the status register read command at any time (even during

a program or erase cycle).

Figure 5 Status Register Read

CS

SCK

SI

SO

MSB

MSB

MSB

05h

DATA

DATA

High Impedance

8

3

2

1

0

7

6

5

4

15

23

Mode 3

Mode 0

8CLK

16

DATA

MSB