AM29LV004 Просмотр технического описания (PDF) - Advanced Micro Devices

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AM29LV004

4 Megabit (512 K x 8-Bit) CMOS 3.0 Volt-only Boot Sector Flash Memory

Advanced Micro Devices 

PRELIMINARY

Table 4. Am29LV004 Autoselect Codes (High Voltage Method)

Description

Manufacturer ID: AMD

Device ID: Am29LV004T

(Top Boot Block)

Device ID: Am29LV004B

(Bottom Boot Block)

Sector Protection Verification

A18 A12

A8

A5

to to

to

to

CE# OE# WE# A13 A10 A9 A7 A6 A2 A1 A0

L

L

H

X X VID X

L

X

L

L

L

L

H

X

X VID X

L

X

LH

DQ7

to

DQ0

01h

B5h

L

L

H

X

X VID X

L

X

LH

B6h

01h

(protected)

L

L

H SA X VID X L X H L

00h

(unprotected)

L = Logic Low = VIL, H = Logic High = VIH, SA = Sector Address, X = Don’t care.

Sector Protection/Unprotection

The hardware sector protection feature disables both

program and erase operations in any sector. The hard-

ware sector unprotection feature re-enables both pro-

gram and erase operations in previously protected

sectors.

The device is shipped with all sectors unprotected.

AMD offers the option of programming and protecting

sectors 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 is protected

or unprotected. See “Autoselect Mode” for details.

Sector protection/unprotection must be implemented

using programming equipment.The procedure requires

a high voltage (VID) on address pin A9 and OE#. De-

tails on this method are provided in a supplement, pub-

lication number 20874. Contact an AMD representative

to request a copy.

Temporary Sector Unprotect

This feature allows temporary unprotection of previ-

ously protected sectors to change data in-system. The

Sector Unprotect mode is activated by setting the RE-

SET# pin to VID. During this mode, formerly protected

sectors can be programmed or erased by selecting the

sector addresses. Once VID is removed from the RE-

SET# pin, all the previously protected sectors are

protected again. Figure 1 shows the algorithm, and

Figure 19 shows the timing diagrams, for this feature.

START

RESET# = VID

(Note 1)

Perform Erase or

Program Operations

RESET# = VIH

Temporary Sector

Unprotect Completed

(Note 2)

Notes:

21522A-4

1. All protected sectors unprotected.

2. All previously protected sectors are protected once

again.

Figure 1. Temporary Sector Unprotect Operation

10

Am29LV004

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