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AM29LV081B

8 Megabit (1 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory

Advanced Micro Devices 

DATA SHEET

COMMAND DEFINITIONS

Writing specific address and data commands or se-

quences into the command register initiates device op-

erations. Table 4 defines the valid register command

sequences. Writing incorrect address and data val-

ues or writing them in the improper sequence resets

the device to reading array data.

All addresses are latched on the falling edge of WE# or

CE#, whichever happens later. All data is latched on

the rising edge of WE# or CE#, whichever happens

first. Refer to the appropriate timing diagrams in the

“AC Characteristics” section.

Reading Array Data

The device is automatically set to reading array data

after device power-up. No commands are required to

retrieve data. The device is also ready to read array

data after completing an Embedded Program or Em-

bedded Erase algorithm.

After the device accepts an Erase Suspend com-

mand, the device enters the Erase Suspend mode.

The system can read array data using the standard

read timings, except that if it reads at an address

within erase-suspended sectors, the device outputs

status data. After completing a programming opera-

tion in the Erase Suspend mode, the system may

once again read array data with the same exception.

See “Erase Suspend/Erase Resume Commands” for

more information on this mode.

The system must issue the reset command to re-en-

able the device for reading array data if DQ5 goes high,

or while in the autoselect mode. See the “Reset Com-

mand” section, next.

See also “Requirements for Reading Array Data” in the

“Device Bus Operations” section for more information.

The Read Operations table provides the read parame-

ters, and Figure 13 shows the timing diagram.

Reset Command

Writing the reset command to the device resets the de-

vice to reading array data. Address bits are don’t care

for this command.

The reset command may be written between the se-

quence cycles in an erase command sequence before

erasing begins. This resets the device to reading array

data. Once erasure begins, however, the device ig-

nores reset commands until the operation is complete.

The reset command may be written between the se-

quence cycles in a program command sequence be-

fore programming begins. This resets the device to

reading array data (also applies to programming in

Erase Suspend mode). Once programming begins,

however, the device ignores reset commands until the

operation is complete.

The reset command may be written between the se-

quence cycles in an autoselect command sequence.

Once in the autoselect mode, the reset command must

be written to return to reading array data (also applies

to autoselect during Erase Suspend).

If DQ5 goes high during a program or erase operation,

writing the reset command returns the device to read-

ing array data (also applies during Erase Suspend).

Autoselect Command Sequence

The autoselect command sequence allows the host

system to access the manufacturer and devices codes,

and determine whether or not a sector is protected.

Table 4 shows the address and data requirements. This

method is an alternative to that shown in Table 3, which

is intended for PROM programmers and requires VID

on address bit A9.

The autoselect command sequence is initiated by writ-

ing two unlock cycles, followed by the autoselect com-

mand. The device then enters the autoselect mode,

and the system may read at any address any number

of times, without initiating another command sequence.

A read cycle at address 00h retrieves the manufacturer

code. A read cycle at address 01h returns the device

code. A read cycle containing a sector address (SA)

and the address 02h returns 01h if that sector is pro-

tected, or 00h if it is unprotected. Refer to Table 2 for

valid sector addresses.

The system must write the reset command to exit the

autoselect mode and return to reading array data.

Byte Program Command Sequence

The byte program command sequence programs one

byte into the device. Programming is a four-bus-cycle

operation. The program command sequence is initi-

ated by writing two unlock write cycles, followed by the

program set-up command. The program address and

data are written next, which in turn initiate the Embed-

ded Program algorithm. The system is not required to

provide further controls or timings. The device auto-

matically generates the program pulses and verifies the

programmed cell margin. Table 4 shows the address

and data requirements for the byte program command

sequence.

When the Embedded Program algorithm is complete,

the device then returns to reading array data and ad-

dresses are no longer latched. The system can deter-

mine the status of the program operation by using DQ7,

DQ6, or RY/BY#. See “Write Operation Status” for in-

formation on these status bits.

Any commands written to the device during the Em-

bedded Program Algorithm are ignored. Note that a

hardware reset immediately terminates the program-

ming operation. The Byte Program command se-

12

Am29LV081B

21525D6 October 12, 2006

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