S71AL016D datasheet(21/76 Pages) SPANSION

21 / 76 page

August 4, 2004 S29AL016D_00_A1_E

S29AL016D

Ad vance

Info rmat i o n

It is possible to determine whether a sector is protected or unprotected. See “Au-

toselect Mode” for details.

Sector protection/unprotection can be implemented via two methods.

The primary method requires VID on the RESET# pin only, and can be imple-

mented either in-system or via programming equipment. Figure 2 shows the

algorithms and Figure 23 shows the timing diagram. This method uses standard

microprocessor bus cycle timing. For sector unprotect, all unprotected sectors

must first be protected prior to the first sector unprotect write cycle.

The alternate method intended only for programming equipment requires VID on

address pin A9 and OE#. This method is compatible with programmer routines

written for earlier 3.0 volt-only Spansion flash devices. Details on this method are

provided in a supplement, publication number 21468. Contact a Spansion repre-

sentative to request a copy.

Temporary Sector Unprotect

This feature allows temporary unprotection of previously protected sectors to

change data in-system. The Sector Unprotect mode is activated by setting the

RESET# pin to VID. During this mode, formerly protected sectors can be pro-

grammed or erased by selecting the sector addresses. Once VID is removed from

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

the algorithm, and Figure 22 shows the timing diagrams, for this feature.

Figure 1. Temporary Sector Unprotect Operation

START

Perform Erase or

Program Operations

RESET# = VIH

Temporary Sector

Unprotect Completed

(Note 2)

RESET# = VID

(Note 1)

Notes:

1. All protected sectors unprotected.

2. All previously protected sectors are protected once

again.

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