AM29F040B-120EE View Datasheet(PDF) - Spansion Inc.

Part Name

Description

Manufacturer

AM29F040B-120EE

4 Megabit (512 K x 8-Bit) CMOS 5.0 Volt-only/ Uniform Sector Flash Memory

Spansion Inc. 

DATA SHEET

COMMAND DEFINITIONS

Writing specific address and data commands or se-

quences into the command register initiates device

operations. The Command Definitions table defines the

valid register command sequences. Writing incorrect

address and data values or writing them in the im-

proper 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 command,

the device enters the Erase Suspend mode. The sys-

tem 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 operation 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 infor-

mation 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 Read Operation Timings diagram 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

before 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.

The Command Definitions table shows the address

and data requirements. This method is an alternative to

that shown in the Autoselect Codes (High Voltage

Method) table, which is intended for PROM program-

mers and requires VID on address bit A9.

The autoselect command sequence is initiated by writ-

ing two unlock cycles, followed by the autoselect

command. 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 XX00h or retrieves the manu-

facturer code. A read cycle at address XX01h returns

the device code. A read cycle containing a sector ad-

dress (SA) and the address 02h in returns 01h if that

sector is protected, or 00h if it is unprotected. Refer to

the Sector Address tables 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

Programming is a four-bus-cycle operation. The pro-

gram command sequence is initiated 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 Embedded Program al-

gorithm. The system is not required to provide further

controls or timings. The device automatically provides

internally generated program pulses and verify the pro-

grammed cell margin. The Command Definitions take

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

determine the status of the program operation by using

DQ7 or DQ6. See “Write Operation Status” for informa-

tion on these status bits.

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Am29F040B

21445E6 March 3, 2009

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