M29F002 データシートの表示（PDF） - Advanced Micro Devices

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M29F002

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

Advanced Micro Devices 

PRELIMINARY

commands can be assumed to be less than 50 µs, the

system need not monitor DQ3. Any command other

than Sector Erase or Erase Suspend during the

time-out period resets the device to reading array

data. The system must rewrite the command sequence

and any additional sector addresses and commands.

The system can monitor DQ3 to determine if the sector

erase timer has timed out. (See the “DQ3: Sector Erase

Timer” section.) The time-out begins from the rising

edge of the final WE# pulse in the command sequence.

Once the sector erase operation has begun, only the

Erase Suspend command is valid. All other commands

are ignored. On the Am29F002 only, note that a hard-

ware reset during the sector erase operation immedi-

ately terminates the operation. The Sector Erase

command sequence should be reinitiated once the de-

vice has returned to reading array data, to ensure data

integrity.

When the Embedded Erase algorithm is complete, the

device returns to reading array data and addresses are

no longer latched. The system can determine the sta-

tus of the erase operation by using DQ7, DQ6, or DQ2.

Refer to “Write Operation Status” for information on

these status bits.

Figure 3 illustrates the algorithm for the erase opera-

tion. Refer to the Erase/Program Operations tables in

the “AC Characteristics” section for parameters, and to

the Sector Erase Operations Timing diagram for timing

waveforms.

START

Write Erase

Command Sequence

Data Poll

from System

No

Data = FFh?

Embedded

Erase

algorithm

in progress

Yes

Erasure Completed

20818C-6

Notes:

1. See the appropriate Command Definitions table for erase

command sequence.

2. See “DQ3: Sector Erase Timer” for more information.

Figure 3. Erase Operation

Am29F002/Am29F002N

13

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