S71AL016M datasheet(23/68 Pages) SPANSION

23 / 68 page

February 23, 2005 S71AL016M_M0_A0

S71AL016M

Advanc e

Informatio n

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

Autoselect Mode on page 22 for details.

Sector protection and unprotection requires VID on the RESET# pin only, and

can be implemented either in-system or via programming equipment. Figure 2,

on page 24 shows the algorithms and Figure 21, on page 54 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.

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.

Figure 1 shows the algorithm, and Figure 22, on page 56 shows the timing dia-

grams, for this feature.

Notes:

1. All protected sectors unprotected.

2. All previously protected sectors are protected once again.

Figure 1. Temporary Sector Unprotect Operation

START

Perform Erase or

Program Operations

RESET# = VIH

Temporary Sector

Unprotect Completed

(Note 2)

RESET# = VID

(Note 1)

S71AL016M Datasheet(PDF) 23 Page - SPANSION