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Features

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Status registers

This IC has status registers. The status registers are of 8 bits and express the following parameters.

BP0 and BP1 can be set by write status register command. These 2 bits are memorized into the EEPROM, therefore are

valid even when power source is turned off.

Rewrite characteristics and data hold time are same as characteristics of the EEPROM.

WEN can be set by write enable command and write disable command. WEN becomes write disable status when power

source is turned off. R/B is for write confirmation, therefore cannot be set externally.

The value of status register can be read by read status command.

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Status registers

Product number

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

BR25H010-W

BR25H020-W

BR25H040-W

1

1

1

1

BP1

BP0

WEN

R/B

BR25H080-W

BR25H160-W

BR25H320-W

WPEN

0

0

0

BP1

BP0

WEN

R/B

bit

Memory

location

Function

Contents

WPEN EEPROM

WPB pin enable / disable designation bit

WPEN=0=invalid

WPEN=1=valid

This enables / disables the functions

of WPB pin.

BP1

BP0

EEPROM

EEPROM write disable block designation bit

This designates the write disable area

of EEPROM. Write designation areas

of product numbers are shown below.

WEN

Register

Write and write status register write enable / disable status confirmation bit

WEN=0=prohibited

WEN=1=permitted

R/B

Register

Write cycle status (READY / BUSY) status confirmation bit

R/B=0=READY

R/B=1=BUSY

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Write disable block setting

Write disable block

BP1

BP0

BR25H010-W

BR25H020-W

BR25H040-W

BR25H080-W

BR25H160-W

BR25H320-W

0

0

None

None

None

None

None

None

0

1

60h-7Fh

C0h-FFh

180h-1FFh

300h-3FFh

600h-7FFh

C00h-FFFh

1

0

40h-7Fh

80h-FFh

100h-1FFh

200h-3FFh

400h-7FFh

800h-FFFh

1

1

00h-7Fh

00h-FFh

000h-1FFh

000h-3FFh

000h-7FFh

000h-FFFh

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WPB pin

By setting WPB=LOW, write command is prohibited. As for BR25H080, 160, 320-W, only when WPEN bit is set “1”, the WPB

pin functions become valid. And the write command to be disabled at this moment is WRSR. As for BR25H010, 020,040-W,

both WRITE and WRSR commands are prohibited.

However, when write cycle is in execution, no interruption can be made.

Product number

WRSR

WRITE

BR25H010-W

BR25H020-W

BR25H040-W

Prohibition

possible

Prohibition

possible

BR25H080-W

BR25H160-W

BR25H320-W

Prohibition possible

but WPEN bit “1”

Prohibition

impossible

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HOLDB pin

By HOLDB pin, data transfer can be interrupted. When SCK=”1”, by making HOLDB from “1” into”0”, data transfer to

EEPROM is interrupted. When SCK = “0”, by making HOLDB from “0” into “1”, data transfer is restarted.