S29AS008J datasheet(21/55 Pages) SPANSION

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November 9, 2011 S29AS008J_00_09

S29AS008J

Data

She e t

7.12

Temporary Sector Group Unprotect

This feature allows temporary unprotection of previously protected sectors to change data in-system. The

Sector Group Unprotect mode is activated by setting the RESET# pin to VID. During this mode, formerly

protected sectors can be programmed or erased by selecting the sector addresses. Once VID is removed

from the RESET# pin, all the previously protected sectors are protected again. Figure 7.2 shows the

algorithm, and Figure 18.10 on page 49 shows the timing diagrams, for this feature. If the WP# pin is at VIL,

the sectors protected by the WP# input will remain protected during the Temporary Sector Group Unprotect

mode.

Figure 7.2 Temporary Sector Group Unprotect Operation

Notes

1. All protected sector groups unprotected.

2. All previously protected sector groups are protected once again.

7.13

Write Protect (WP#)

The Write Protect function provides a hardware method of protecting certain boot sectors without using VID.

This function is one of two provided by the WP# pin.

If the system asserts VIL on the WP# pin, the device disables program and erase functions in the two

outermost 8-Kbyte boot sectors independently of whether those sectors were protected or unprotected using

the method described in Section 7.11, Sector Group Protection/Unprotection on page 19. The two outermost

8-Kbyte boot sectors are the two sectors containing the lowest addresses in a bottom-boot-configured device,

or the two sectors containing the highest addresses in a top-boot-configured device.

If the system asserts VIH on the WP# pin, the device reverts to whether the two outermost 8-KByte boot

sectors were last set to be protected or unprotected. That is, sector group protection or unprotection for these

two sectors depends on whether they were last protected or unprotected using the method described in

Section 7.11.

The WP# contains an internal pull-up; when unconnected, WP is at VIH.

START

Perform Erase or

Program Operations

RESET# = VIH

Temporary Sector Group

Unprotect Completed

(Note 2)

RESET# = VID

(Note 1)

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