AM29LV642D datasheet(21/53 Pages) AMD

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Am29LV642D

P R E L I M I NARY

Sector Group Protection and

Unprotection

The hardware sector group protection feature disables

both program and erase operations in any sector

group. In this device, a sector group consists of four

adjacent sectors that are protected or unprotected at

the same time (see Table 5). The hardware sector

group unprotection feature re-enables both program

and erase operations in previously protected sector

groups. Sector group protection/unprotection can be

implemented via two methods.

The primary method requires V

ID on the RESET# pin

only, and can be implemented either in-system or via

programming equipment. Figure 2 shows the algo-

rithms and Figure 22 shows the timing diagram. This

method uses standard microprocessor bus cycle tim-

ing. For sector group unprotect, all unprotected sector

groups must first be protected prior to the first sector

group unprotect write cycle.

Some earlier 3.0 volt-only AMD flash devices used a

sector protection/unprotection method intended only

for programming equipment, and required V

ID on ad-

dress pin A9 and OE#. If this earlier method is re-

quired for the intended application, contact AMD for

further details.

The device is shipped with all sector groups unpro-

tected. AMD offers the option of programming and

protecting sector groups at its factory prior to shipping

the device through AMD’s ExpressFlash™ Service.

Contact an AMD representative for details.

It is possible to determine whether a sector group is

protected or unprotected. See the Autoselect Mode

section for details.

Table 5.

Sector Group Protection/Unprotection

Address Table

Note: All sector groups are 128 Kwords in size.

Sector Group

A22–A18

SA0–SA3

00000

SA4–SA7

00001

SA8–SA11

00010

SA12–SA15

00011

SA16–SA19

00100

SA20–SA23

00101

SA24–SA27

00110

SA28–SA31

00111

SA32–SA35

01000

SA36–SA39

01001

SA40–SA43

01010

SA44–SA47

01011

SA48–SA51

01100

SA52–SA55

01101

SA56–SA59

01110

SA60–SA63

01111

SA64–SA67

10000

SA68–SA71

10001

SA72–SA75

10010

SA76–SA79

10011

SA80–SA83

10100

SA84–SA87

10101

SA88–SA91

10110

SA92–SA95

10111

SA96–SA99

11000

SA100–SA103

11001

SA104–SA107

11010

SA108–SA111

11011

SA112–SA115

11100

SA116–SA119

11101

SA120–SA123

11110

SA124–SA127

11111

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