AM29F200 View Datasheet(PDF) - Advanced Micro Devices

Part Name

Description

Manufacturer

AM29F200

2 Megabit (256 K x 8-Bit/128 K x 16-Bit) CMOS 5.0 Volt-only, Boot Sector Flash Memory

Advanced Micro Devices 

Table 4. Am29F200B Autoselect Codes (High Voltage Method)

Description

A16 A11

A8

A5

DQ8

to to

to

to

to

Mode CE# OE# WE# A12 A10 A9 A7 A6 A2 A1 A0 DQ15

DQ7

to

DQ0

Manufacturer ID: AMD

L

L

H X X VID X L X L L

X

01h

Device ID:

Word L

L

H

22h

51h

Am29F200B

X X VID X L X L H

(Top Boot Block)

Byte L

L

H

X

51h

Device ID:

Word L

L

H

22h

57h

Am29F200B

X X VID X L X L H

(Bottom Boot Block) Byte L

L

H

X

57h

Sector Protection Verification L

L

H SA X VID X L X H L

X

01h

(protected)

X

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

program and erase operations in previously protected

sectors.

Sector protection/unprotection must be implemented

using programming equipment. The procedure

requires a high voltage (VID) on address pin A9 and the

control pins. Details on this method are provided in a

supplement, publication number 20551. Contact an

AMD representative to obtain a copy of the appropriate

document.

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.

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

RESET# pin to VID. During this mode, formerly pro-

tected 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 algo-

rithm, and the Temporary Sector Unprotect diagram

(Figure 18) shows the timing waveforms, for this

feature.

START

RESET# = VID

(Note 1)

Perform Erase or

Program Operations

RESET# = VIH

Temporary Sector

Unprotect

Completed (Note 2)

Notes:

1. All protected sectors unprotected.

21526B-6

2. All previously protected sectors are protected once

again.

Figure 1. Temporary Sector Unprotect Operation

Hardware Data Protection

The command sequence requirement of unlock cycles

for programming or erasing provides data protection

against inadvertent writes (refer to the Command Defi-

nitions table). In addition, the following hardware data

protection measures prevent accidental erasure or pro-

Am29F200B

11

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