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AS8F128K32

Austin Semiconductor, Inc.

AS8F128K32

Rev. 2.0 5/03

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

5

Sector Protection/Unprotection

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/unprotection must be implemented

using programming equipment. The procedure requires a high

voltage (V

The device is shipped with all sectors unprotected. It is

possible to determine whether a sector is protected or

unprotected. See “Autoselect Mode” for details.

Hardware Data Protection

The command sequence requirement of unlock cycles for

programming or erasing provides data protection against

inadvertent writes (refer to the Command Definitions table). In

addition, the following hardware data protection measures

prevent accidental erasure or programming, which might

otherwise be caused by spurious system level signals during

V

noise.

Low VCC Write Inhibit

When V

any write cycles. This protects data during V

power-down. The command register and all internal program/

erase circuits are disabled, and the device resets. Subsequent

writes are ignored until V

must provide the proper signals to the control pins to prevent

unintentional writes when V

Write Pulse “Glitch” Protection

Noise pulses of less than 5 ns (typical) on OE\, CEx\ or

WEx\ do not initiate a write cycle.

Logical Inhibit

Write cycles are inhibited by holding any one of OE\ = V

CEx\ = V

WEx\ must be a logical zero while OE\ is a logical one.

Power-Up Write Inhibit

If WEx\ = CEx\ = V

does not accept commands on the rising edge of WEx\. The

internal state machine is automatical ly reset to reading array

data on power-up.

TABLE 3: Autoselect Codes (High Voltage Method)

DESCRIPTION

CEx\

OE\

WEx\

A16

to

A14

A13

to

A10

A9

A8 to

A7

A6

A5

to

A2

A1

A0

I/O0 to I/O7

I/O8 to I/O15

I/O16 to I/O23

I/O24 to I/O31

Manufacturer ID: AMD

LL

H

X

X

XL

X

L

L

01h

Device ID: AM29F010B

LL

H

X

X

XL

X

L

H

20h

01h (protected)

00h

(unprotected)

Sector Protection Verification

LL

H

SA

X

XL

X

H

L

LEGEND:

L = Logic Low = V