A29DL323 datasheet(15/50 Pages) AMICC

15 / 50 page

A29DL32x Series

PRELIMINARY

(May, 2005, Version 0.0)

AMIC Technology, Corp.

The hardware sector protection feature disables both

program and erase operations in any sector. The hardware

sector unprotection feature re-enables both program and

erase operations in previously protected sectors. Sector

protection and unprotection can be implemented via two

methods.

The primary method requires VID on the RESET pin only,

and

can

implemented

either

in-system

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 sector unprotect algorithm unprotects all sectors in

parallel. All previously protected sectors must be individually

re-protected. To change data in protected sectors efficiently,

the temporary sector unprotect function is available. See

“Temporary Sector/Sector Block Unprotect”.

The alternate method for protection and unprotection is by

software sector /sector block protect unprotect command.

See Figure 2 for Command Flow.

The device is shipped with all sectors unprotected.

It is possible to determine whether a sector is protected or

unprotected. See the Autoselect Mode section for details.

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 /ACC pin.

If the system asserts VIL on the WP /ACC 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

“Sector/Sector Block Protection and Unprotection”. 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 /ACC pin, the device

reverts to whether the two outermost 8 Kbyte boot sectors

were last set to be protected or unprotected. That is, sector

protection or unprotection for these two sectors depends on

whether they were last protected or unprotected using the

method described in “Sector/Sector Block Protection and

Unprotection”.

Note that the WP /ACC pin must not be left floating or

unconnected; inconsistent behavior of the device may result.

Temporary Sector/Sector Block Unprotect

(Note: For the following discussion, the term “sector” applies

to both sectors and sector blocks. A sector block consists of

two or more adjacent sectors that are protected or

unprotected at the same time (see Tables 6 and 7).

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

(8.5V-12.5V). 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 1

shows the algorithm, and Figure 22 shows the timing

diagrams, for this feature.

A29DL323 Datasheet(PDF) 15 Page - AMIC Technology

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