25AA040-ESLASHST datasheet(9/22 Pages) MICROCHIP

Part #	25AA040-E/ST

Description	4K SPI ??Bus Serial EEPROM

PDF	22 Pages

Scroll/Zoom	100%

Manufacturer	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

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9 / 22 page

DS21204E-page 9

25AA040/25LC040/25C040

3.4

Write Enable (WREN) and Write

Disable (WRDI)

The 25XX040 contains a write enable latch.

See

Table 3-3 for the Write-Protect Functionality Matrix.

This latch must be set before any write operation will be

completed internally. The WREN instruction will set the

latch, and the WRDI will reset the latch.

The following is a list of conditions under which the

write enable latch will be reset:

• Power-up

• WRDI instruction successfully executed

• WRSR instruction successfully executed

• WRITE instruction successfully executed

•WP line is low

FIGURE 3-4:

WRITE ENABLE SEQUENCE

FIGURE 3-5:

WRITE DISABLE SEQUENCE

SCK

234567

High-impedance

0000

SCK

234567

High-impedance

0000

25AA040-E/ST Datasheet(PDF) 9 Page - Microchip Technology