S-25C040A0I-T8T1G View Datasheet(PDF) - Seiko Instruments Inc

Part Name

Description

MFG CO.

S-25C040A0I-T8T1G

CMOS SPI SERIAL E2PROM

Seiko Instruments Inc 

Rev.1.0_00

CMOS SPI SERIAL E2PROM

S-25C010A/020A/040A

5. Write in the status register (WRSR)

The values of status register (BP1, BP0) can be rewritten by inputting the WRSR instruction. But b7, b6, b5, b4, b1, b0 of

status register cannot be rewritten. b7 to b4 are always “1” when reading the status register.

Before inputting the WRSR instruction, set bit WEL by the WREN instruction. The operation of WRSR is shown below.

Set the chip select ( CS ) “L” first. After that, input the instruction code and data from serial data input (SI). To start

WRSR Write (tPR), set the chip select ( CS ) to “H” after inputting data or before inputting a rising of the next serial clock.

It is possible to confirm the operation status by reading the value of bit WIP during WRSR Write. Bit WIP is “1” during

Write, “0” during any other status. Bit WEL is reset when Write is completed.

With the WRSR instruction, the values of BP1 and BP0; which determine the area size the users can handle as the Read

Only memory; can be changed. But if the signal WP is in “L”, S-25C010A/020A/040A does not send the WRSR

instruction (Refer to “„ Protect Operation”).

Bit BP1, BP0 keep the value which is the one prior to the WRSR instruction during the WRSR instruction. The newly

updated value is changed when the WRSR instruction has completed.

To cancel the WRSR instruction, input the clock different from a specified value (n = 16clock) while CS is in “L”.

CS

WP

High / Low

SCK

SI

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Instruction

Inputs Data in the Status Register

X

b7 b6 b5 b4 b3 b2 b1 b0

SO

Remark X = Don’t care.

High-Z

Figure 14 WRSR operation

Seiko Instruments Inc.

15

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