AM29F032B datasheet(13/39 Pages) AMD

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Am29F032B

Sector Group Protection/Unprotection

The hardware sector group protection feature disables

both program and erase operations in any sector

group. Each sector group consists of four adjacent

sectors. Table 4 shows how the sectors are grouped,

and the address range that each sector group con-

tains. The hardware sector group unprotection feature

re-enables both program and erase operations in pre-

viously protected sector groups.

Sector group protection/unprotection must be imple-

mented using programming equipment. The proce-

dure requires a high voltage (V

ID) on address pin A9

and the control pins. Details on this method are pro-

vided in a supplement, publication number 22184.

Contact an AMD representative to obtain a copy of the

appropriate document.

The device is shipped with all sector groups unpro-

tected. AMD offers the option of programming and pro-

tecting sector groups at its factory prior to shipping the

device through AMD’s ExpressFlash™ Service. Con-

tact an AMD representative for details.

It is possible to determine whether a sector group is

protected or unprotected. See “Autoselect Mode” for

details.

Table 4.

Sector Group Addresses

Temporary Sector Group Unprotect

This feature allows temporary unprotection of previ-

ously protected sector groups to change data in-sys-

tem. The Sector Group Unprotect mode is activated by

setting the RESET# pin to V

ID (11.5 V – 12.5 V). Dur-

ing this mode, formerly protected sector groups can be

programmed or erased by selecting the sector group

addresses. Once V

ID is removed from the RESET#

pin, all the previously protected sector groups are

protected again. Figure 1 shows the algorithm, and

Figure 16 shows the timing diagrams, for this feature.

Figure 1.

Temporary Sector Group Unprotect

Operation

Sector

Group

A21

A20

A19

A18

Sectors

SGA0

SA0

–SA3

SGA1

SA4

–SA7

SGA2

SA8

–SA11

SGA3

SA12

–SA15

SGA4

SA16

–SA19

SGA5

SA20

–SA23

SGA6

SA24

–SA27

SGA7

SA28

–SA31

SGA8

SA32–SA35

SGA9

SA36–SA39

SGA10

SA40–SA43

SGA11

SA44–SA47

SGA12

SA48–SA51

SGA13

SA52–SA55

SGA14

SA56–SA59

SGA15

SA60–SA63

START

Perform Erase or

Program Operations

RESET# = V

Temporary Sector Group

Unprotect Completed

(Note 2)

RESET# = V

(Note 1)

Notes:

1. All protected sector groups unprotected.

2. All previously protected sector groups are protected

once again.

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