AMD Advanced Micro Devices Am29F040B-90JC, AM29F040B-120JC, Am29F040B-70JC Datasheet

Am29F040B

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

DISTINCTIVE CHARACTERISTICS

■ 5.0 V ± 10% for read and write operations

— Minimizes system level power requirements

■ Manufactured on 0.32 µm process technology

— Compatible with 0.5 µm Am29F040 device

■ High performance

— Access times as fast as 55 ns

■ Low power consumption

— 20 mA typical active read current — 30 mA typical program/erase current — 1 µA typical standby current (standard access

time to active mode)

■ Embedded Algorithms

— Embedded Erase algorithm automatically

preprograms and erases the entire chip or any combination of designated sectors

— Embedded Program algorithm automatically

writes and verifies bytes at specified addresses

■ Minimum 1,000,000 program/er ase cycles per

sector guaranteed

■ 20-year data retention at 125°C

— Reliable operation for the life of the system

■ Package options

— 32-pin PLCC, TSOP, or PDIP

■ Flexible sector arc hitecture

— 8 uniform sectors of 64 Kbytes each — Any combination of sectors can be erased — Supports full chip erase — Sector protection:

A hardware method of locking sectors to prevent any program or erase operations within that sector

■ Compatible with JEDEC standards

— Pinout and software compatible with

single-power-supply Flash standard

— Superior inadvertent write protection

■ Data# Polling and toggle bits

— Provides a software method of detecting

program or erase cycle completion

■ Erase Suspend/Erase Resume

— Suspends a sector erase operation to read data

from, or program data to, a non-erasing sector , then resumes the erase operation

This Data Sheet states AMD’s current technical specifications regarding the Products described herein. This Data Sheet may be revised by subsequent versions or modifications due to changes in technical specifications.

Publication# 21445 Rev: E Amendment/0 Issue Date: November 29, 2000

GENERAL DESCRIPTION

The Am29F040B is a 4 Mbit, 5.0 volt-only Flash memory organized as 524,288 Kbytes of 8 bits each. The 512 Kbytes of data are divided into eight sectors of 64 Kbytes each for flexible erase capability. The 8 bits of

data appear on DQ0–DQ7. The Am29F040B is offered in 32-pin PLCC, TSOP, and PDIP packages. This device is designed to be programmed in-system w ith the standard system 5.0 volt V required for write or erase operations. The device can also be programmed in standard EPROM programmers.

This device is manufactured using AMD’ s 0. 32 µm process techno logy, and offers all the features and benefits of the Am29F040, which was manufactured using 0.5 µm process technology. In addtion, the Am29F040B has a second toggle bit, DQ2, and also offers the ability to progr am in the Er ase Suspend mode .

The standard Am29F040B o ffers access times of 55, 70, 90, 120, and 150 ns, allowing high-s peed microprocessors to operate without w ait states . To eliminate bus contention the device has separate chip enable (CE#), write enable (WE#) and output enable (OE#) controls.

The device requires only a single 5. 0 v o lt po wer sup- ply for both read and write functions. Internally generated and regulated voltages are provided for the program and erase operations.

The device is entirely command set compatible with the JEDEC single-power-supply Flash standard. Commands are written to the command regis ter using standard micropr ocessor wri te timings. Register co ntents serve as input to an internal state-machine that controls the erase and programming ci rcuitry. Write cycles also internally latch add resses and data needed for the programming and erase operations. Reading data out of the device is similar to reading from other Flash or EPROM devices.

Device programming occurs by executing the program command sequence. This initiates the Embedded Program algorithm—an internal algorithm that auto-

supply. A 12.0 volt VPP is not

matically times the program pulse widths an d verifies proper cell margin.

Device erasure occurs by executing the erase command sequenc e. This initiates the Embedded Erase algorithm—an in ternal algorithm that auto matically preprograms the arra y (if it is not already progr ammed) before e xecuting the er ase operation. During erase, the device automatically times the erase pulse widths and verifies proper cell margin.

The host system can detect whether a program or erase operation is complete by reading the DQ7 (Data# Polling) and DQ6 (toggle) status bits. After a program or erase cycle has been completed, the de vice is ready to read array data or accept another command.

The sector erase ar chitecture allo ws memo ry secto rs to be erased and reprogrammed without affecting the data contents of other sectors. The device is fully erased when shipped from the factory.

Hardware data protection measures include a low

detector that automatically in hibits write opera-

tions during power transitions. The hardware sector protection feature disables both program and erase

operations in any combination of the sectors of memory . This can be achie v ed via prog ramming equipment.

The Erase Suspend feature enables the user to put erase on hold for any period of time to read data from, or program data to, any sector that is not selected for erasure. True background erase can thus be achieved.

The system can place the devic e into the standb y mode. Power consumption is greatly reduced in this mode.

AMD’s Flash technology combines years of Flash memory manufacturing experience to produce the highest levels of quality, reliability and cost effectiveness. The device electrically erases all bi ts within a sector simultaneously via Fowler-Nordheim tunneling. The data is programmed using hot electron injection.

2 Am29F040B

TABLE OF CONTENTS

Product Selector Guide. . . . . . . . . . . . . . . . . . . . . 4

Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Connection Diagrams . . . . . . . . . . . . . . . . . . . . . . 5

Pin Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . 6

Logic Symbol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Ordering Information. . . . . . . . . . . . . . . . . . . . . . . 7

Device Bus Operations . . . . . . . . . . . . . . . . . . . . . 8

Table 1. Am29F040B Device Bus Operations ..... ................ ..............8

Requirements for Reading Array Data...................... ............... 8

Writing Commands/Command Sequences .... ................... .. .. .. . 8

Program and Erase Operation Status ...................................... 8

Standby Mode ................. .......................... .............. ................. 8

Output Disable Mode................................................................ 9

Table 2. Sector Addresses Table ......................................................9

Autoselect Mode..................................................................... 10

Table 3. Am29F040B Autoselect Codes (High Voltage Method). ....1 0

Sector Protection/Unprotection............................................... 10

Hardware Data Protection ...................................................... 10

Low VCC Write Inhibit...................................................................... 10

Write Pulse “Glitch” Protection........................................................ 10

Logical Inhibit......................... ......... .... ... ....... ......... ....... ...... ... ....... .. 10

Power-Up Write Inhibit.................................................................... 10

Command Definitions . . . . . . . . . . . . . . . . . . . . . 11

Reading Array Data........................... ..................................... 11

Reset Command..................................................................... 11

Autoselect Command Sequence............................................ 11

Byte Program Command Sequence.............. ............... .......... 11

Figure 1. Program Operation......................................................... 12

Chip Erase Command Sequence........................................... 12

Sector Erase Command Sequence........................................ 12

Erase Suspend/Erase Resume Commands................. .......... 13

Figure 2. Erase Operation.............................................................. 13

Command Definitions ............................................................. 14

Table 4. Am29F040B Command Definitions....................................14

Write Operation Status . . . . . . . . . . . . . . . . . . . . 15

DQ7: Data# Polling................................................................. 15

Figure 3. Data# Polling Algorithm .................................................. 15

DQ6: Toggle Bit I.................................................................... 16

DQ2: Toggle Bit II ................................................................... 16

Reading Toggle Bits DQ6/DQ2 .............................................. 16

DQ5: Exceeded Timing Limits................................................ 16

DQ3: Sector Erase Timer ....................................................... 17

Figure 4. Toggle Bit Algorithm........................................................ 17

Table 5. Write Operation Status .......................................................18

Absolute Maximum Ratings. . . . . . . . . . . . . . . . . 19

Figure 5. Maximum Negative Overshoot Waveform..................... 19

Figure 6. Maximum Positive Overshoot Waveform....................... 19

Operating Ranges. . . . . . . . . . . . . . . . . . . . . . . . . 19

DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 20

TTL/NMOS Compatible .......................................................... 20

CMOS Compatible.................................................................. 20

Test Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 7. Test Setup..................................................................... 21

Table 6. Test Specifications........................................................... 21

Key to Switching Waveforms. . . . . . . . . . . . . . . . 21

AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 22

Read Only Operations............................. .............. ................. 22

Figure 8. Read Operation Timings................................................ 22

Erase and Program Operations................... ........................... 23

Figure 9. Program Operation Timings........................................... 24

Figure 10. Chip/Sector Erase Operation Timings ......................... 24

Figure 11. Data# Polling Timings (During Embedded Algorithms) 25

Figure 12. Toggle Bit Timings (During Embedded Algorithms)..... 25

Figure 13. DQ2 vs. DQ6................................................................ 26

AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 27

Erase and Program Operations................... ........................... 27

Alternate CE# Controlled Writes.................................................... 27

Figure 14. Alternate CE# Controlled Write Operation Timings ..... 28

Erase and Programming Performance. . . . . . . . 29

Latchup Characteristics. . . . . . . . . . . . . . . . . . . . 29

TSOP Pin Capacitance . . . . . . . . . . . . . . . . . . . . 29

PLCC and PDIP Pin Capacitance. . . . . . . . . . . . . 30

Data Retention. . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . 31

PD 032—32-Pin Plastic DIP................................................... 31

PL 032—32-Pin Plastic Leaded Chip Carrier......................... 32

TS 032—32-Pin Standard Thin Small Package...................... 33

TSR032—32-Pin Reversed Thin Small Outline Pa ckage....... 34

Revision Summary . . . . . . . . . . . . . . . . . . . . . . . . 35

Revision A (May 1997) ............................................... .. .......... 35

Revision B (January 1998) ..................................................... 35

Revision B+1 (January 1998)................................................. 35

Revision B+2 (April 1998)....................................................... 35

Revision C (January 1999)................................. .................... 35

Revision C+1 (February 1999) ............................................... 35

Revision C+2 (May 17, 1999) ................................................. 35

Revision D (November 15, 1999) ........................................... 35

Revision E (November 29, 2000)............................. .. ............. 35

Am29F040B 3

PRODUCT SELECTOR GUIDE

Family Part Number Am29F040B

= 5.0 V ± 5% -55

Speed Option

Max access time, ns (t Max CE# access time, ns (t Max OE# access time, ns (t

= 5.0 V ± 10% -70 -90 -120 -150

) 55 70 90 120 150

ACC

) 55 70 90 120 150

) 2530355055

Note: See the “AC Characteristics” section for more information.

BLOCK DIAGRAM

Erase Voltage

Generator

DQ0–DQ7

Input/Output

Buffers

WE#

CE# OE#

A0–A18

State

Control

Command

Detector

PGM Voltage

Generator

Timer

Chip Enable

Output Enable

STB

Logic

Y-Decoder

Address Latch

STB

Data Latch

Y-Gating

Cell MatrixX-Decoder

4 Am29F040B

CONNECTION DIAGRAMS

A18 A16 A15 A12

DQ0 DQ1 DQ2

A11

A8 A13 A14 A17

WE#

A18 A16 A15 A12

A7 A6 A5 A4 A3 A2 A1 A0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

PDIP

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

WE# A17 A14 A13 A8 A9 A11 OE# A10 CE# DQ7 DQ6 DQ5 DQ4 DQ3

A7 A6 A5 A4 A3 A2 A1 A0

DQ0

32-Pin Standard TSOP

5 6 7 8 9 10 11 12 13

A12

DQ1

A15

A16

A18

1313023432

PLCC

17 18 19 20161514

DQ2

DQ3

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

VCCWE#

DQ4

DQ5

OE# A10 CE# DQ7 DQ6 DQ5 DQ4 DQ3 V DQ2 DQ1 DQ0 A0 A1 A2 A3

A17

29 28 27 26 25 24 23 22 21

DQ6

A14 A13 A8 A9 A11 OE# A10 CE# DQ7

OE#

A10

CE# DQ7 DQ6 DQ5 DQ4 DQ3

DQ2 DQ1 DQ0

A0 A1 A2 A3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

32-Pin Reverse TSOP

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

A11 A9 A8 A13 A14 A17 WE# V

A18 A16 A15 A12 A7 A6 A5 A4

Am29F040B 5

PIN CONFIGURATION

A0–A18 = Address Inputs

LOGIC SYMBOL

DQ0–DQ7 = Data Input/Output CE# = Chip Enable WE# = Write Enable OE# = Output Enable V

= +5.0 V single power supply

= Device Ground

(see Product Selector Guide for device speed ratings and voltage supply tolerances)

A0–A18

CE# OE#

WE#

DQ0–DQ7

6 Am29F040B

ORDERING INFORMATION Standard Pr od ucts

AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed by a combination of the following:

Am29F040B -55 E C

DEVICE NUMBER/DESCRIPTION

Am29F040B 4 Megabit (512 K x 8-Bit) CMOS 5.0 Volt-only Sector Erase Flash Memory

5.0 V Read, Program, and Erase

TEMPERATURE RANGE

C=Commercial (0°C to +70°C) I = Industrial (–40

E = Extended (–55

PACKAGE TYPE

P = 32-Pin Plastic DIP (PD 032) J = 32-Pin Rectangular Plastic Leaded Chip Carrier (PL 032) E = 32-Pin Thin Small Outline Package (TSOP) Standard Pinout (TS 032) F = 32-Pin Thin Small Outline Package (TSOP) Reverse Pinout (TSR032)

SPEED OPTION

See Product Selector Guide and Valid Combinations

°C to +85°C)

°C to +125°C)

Valid Combinations VCC Voltage

AM29F040B-55 JC, JI, JE, AM29F040B-70 AM29F040B-90

AM29F040B-120 AM29F040B-150

EC, EI, EE,

FC, FI, FE

PC, PI, PE,

JC, JI, JE,

EC, EI, EE,

FC, FI, FE

5.0 V ± 5%

5.0 V ± 10%

Valid Combinations

Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations and to check on newly released combinations.

Am29F040B 7

DEVICE BUS OPERATIONS

This section describes the requirements and use of the device bus operations, which are initiated through the internal c ommand register. The command register itself does not occupy any addressable memory location. The register is composed of latches th at store the commands, along with the address and data infor-

Table 1. Am29F040B Device Bus Operations

Operation CE# OE# WE# A0–A20 DQ0–DQ7

mation needed to execute the command. The contents of the register serve as inputs to the internal state machine. The state machine outputs dictate the function of the device. The appropriate device bus operations table lists the inputs and control le vels requ ired, and the resulting output. The following subsections describe each of these operations in further detail.

Read L L H A Write L H L A CMOS Standby VCC ± 0.5 V X X X High-Z

TTL Standby H X X X High-Z Output Disable L H H X High-Z

Legend:

L = Logic Low = V

Note: See the “Sector Protection/Unprotection” section. for more information.

Requirements for Reading Array Data

To read array data from the outputs, the system must drive the CE# and OE# pins to V control and selects the device. OE# is the output control and gates arra y data to the output pins . WE# should remain at V

The internal state machine is set for reading arr ay data upon device power-up, or after a hardware reset. This ensures that no spurious alteration of the memory content occurs during the power transition. No command is necessary in this mode to obtain array data. Standard microprocessor read cycles that assert valid addresses on the device address input s produc e valid data on the device data outputs. The device remains enabled for read access until the command register contents are altered.

See “Reading Array Data” for more information. Refer to the AC Read Operations table for timing specifications and to the Read Operations Timings diagram for the timing waveforms. I table represents the active current specification for reading array data.

, H = Logic High = VIH, VID = 12.0 ± 0.5 V, X = Don’t Care, DIN = Data In, D

indicate the address space that each sector occupies. A “sector address” consists of the address bits required

. CE# is the power

to uniquely select a sector. See the “Command Definitions” section for details on erasing a sector or the entire chip, or suspending/resuming the erase

operation. After the system writes the autoselect command se-

quence, the device enters the autoselect mode. The system can then read autoselect codes from the internal register (which is separate from the memory array) on DQ7–DQ0. Standard read cycle timings apply in this mode. Refer to the “Autoselect Mode” and “Autoselect Command Sequence” sections for more information.

in the DC Characteristics table represents the ac-

CC2

tive current specification for the write mode. The “AC Characteristics” section contains timing specification tables and timing diagrams for write operations.

Program and Erase Operation Status

in the DC Characteristics

CC1

During an erase or program operation, the system ma y check the status of the operation by reading the status bits on DQ7–DQ0. Standard read cycle timings and I

= Data Out, AIN = Address In

OUT

read specifica tions apply. Refer to “Write Ope ration

Writing Commands/Command Sequences

To wr ite a command or command sequence (which includes programming data to the device and erasing sectors of memory), the system must drive WE# and CE# to V

An erase operation can erase one sect or, multiple sectors, or the entire device. The Sector Address Tables

, and OE# to VIH.

Status” for more information, and to each AC Characteristics section for timing diagrams.

Standby Mode

When the system is not reading or writing to the device , it can place the device in the standby mode. In this mode, current consumption is gr eatly reduced, and the

8 Am29F040B

outputs are placed in the high impedance state, independent of the OE# input.

The device enters the CMOS standby mode when the

0.5 V. (Note that this is a more

CE# pin is held at V restricted voltage rang e than V the TTL standby mode when CE# is held at V device requires the standard ac cess time (t

.) The device enters

) before it

. The

is ready to read data.

If the device is deselected during erasure or programming, the device draws active current until the operation is completed.

in the DC Characteristics tables represents the

CC3

standby current specification.

Output Disable Mode

When the OE# input is at VIH, output from the device is disabled. The output pins are placed in t he high impedance state.

Table 2. Sector Addresses Table

Sector A18 A17 A16 Address Range

SA0 0 0 0 00000h–0FFFFh SA1 0 0 1 10000h–1FFFFh SA2 0 1 0 20000h–2FFFFh SA3 0 1 1 30000h–3FFFFh SA4 1 0 0 40000h–4FFFFh SA5 1 0 1 50000h–5FFFFh SA6 1 1 0 60000h–6FFFFh SA7 1 1 1 70000h–7FFFFh

Note: All sectors are 64 Kbytes in size.

Am29F040B 9

Autoselect Mode

The autoselect mode provides manufacturer and device identification, and sector protection verification,

through identifier codes output on DQ7–DQ0. This mode is primarily intended for progr amming equipment to automatically match a device to be progr ammed with its correspondi ng programming al gorithm. However, the autoselect codes can also be accessed in-system through the command register.

When using programming equipment, the autoselect mode requires V A9. Address pins A6, A1, and A0 must be as shown in Autoselect Codes (High Voltage Method) table. In addition, when verifying sector protection, the sector

Description A18–A16 A15–A10 A9 A8–A7 A6 A5–A2 A1 A0

(11.5 V to 12.5 V) on address pin

Table 3. Am29F040B Autoselect Codes (High Voltage Method)

address must appear on the appropriate highest order address bits. Refer to the corresponding Sector Address Tables. The Command Definitio ns table shows the remaining address bits that are don’t c are. When all necessary bits have been set as required, the programming equipment may then read the corresponding identifier code on DQ7–DQ0.

To access the autoselect codes in-system, the host system can issue the autoselect command via the command register, as shown in the Command Definitions table. This method does not require V

. See

“Command Definitions” for details on using the autoselect mode.

Identifier Code on

DQ7-DQ0

Manufacturer ID: AMD X X V Device ID: Am29F040B X X V

Sector Protection Verification

Sector

Address

Sector Protection/Unprotection

The hardware sector protection feature disables both program and erase operations in any sect or. 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

) on address pin A9 and the

control pins. Details on this method are provided in a supplement, publication number 19957. Contact an AMD representative to obtain a cop y 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™ Servic e. Contact an AMD representative for details.

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 pre vent accidental eras ure or pro-

XVILXVILV XVILXVILV

XVILXVIHV

01h A4h

01h (protected)

00h (unprotected)

gramming, which might otherwise be caused by spurious system level signals during V

power-up and

power-down transitions, or from system noise.

Low V

When V

Write Inhibit

is less than V

, the device does not ac-

LKO

cept any write cycles. This protects data during V power-up and power-down. The command register and all internal program/erase circuits are disabled, and the device resets. Subsequent writes are ignored until V is greater than V

. The system must provide the

LKO

proper signals to the control pins to prevent unintentional writes when V

is greater than V

LKO

Write Pulse “Glitch” Protection

Noise pulses of less than 5 ns (typical) on OE#, CE# or WE# do not initiate a write cycle.

Logical Inhibit

Write cycles are inhibited by holding any one of OE# =

, CE# = VIH or WE# = VIH. To initiate a wr ite cycle,

CE# and WE# must be a logical zero while OE# is a logical one.

Power-Up Write Inhibit

If WE# = CE# = V

and OE# = VIH during power up , the

device does not accept commands on the rising edge of WE#. The internal state mac hine is automatically reset to reading array data on power-up.

10 Am29F040B

COMMAND DEFINITIONS

Writing specific addre ss and data commands or sequences into the command register initiates device operations. The Command Definitions tab le 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 comp leting an Embe dded Program or Embedded Erase algorithm.

After the device accepts an Er ase Suspend command, 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 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 information on this mode.

must

The system able the dev ice f or reading arra y data if DQ5 goes high, or while in the autoselect mode. See the “Reset Command” section, next.

See also “Requirements for Reading Arr a y Data” in the “Device Bus Operations” section for more information. The Read Operations table provides the read parameters, and Read Operation Timings diagram shows the timing diagram.

issue the reset command to re-en-

Reset Command

Writing the reset command to the devi ce resets the device to reading array data. Address bits are don’t care for this command.

The reset command may be written between the sequence cycles in an erase command sequence before erasing begins. This resets the device to reading array data. Once erasure begins, however, the device ignores reset commands until the operation is complete.

The reset command may be written between the sequence 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 sequence cycles in an autoselect command sequence. Once in the autoselect mode, t he reset c ommand 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 reading array data (also applies during Erase Suspend).

must

Autoselect Command Sequence

The autoselect c ommand sequenc e allows the host system to access the manufacturer and de vices codes , and determine whether or not a sector is protected. The Command Definitions table shows the address and data requirements. This method is an a lternative to that shown in the Autoselect Codes (High Voltage Method) table, which is in tended for PROM programmers and requires V

The autoselect command sequence is initiated by writing 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 manufacturer code. A read cycle at address XX01h returns the device code. A read cycle containing a sector address (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.

on address bit A9.

Byte Program Command Sequence

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

not

gorithm. The system is controls or timings. The device automatically provides internally generated program pulses and v erify the programmed 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 addresses are no longer latched. The system can determine the status of the program operation by using DQ7 or DQ6. See “Write Operat ion Status ” f or inf ormation on these status bits.

required to provide further

Am29F040B 11

+ 24 hidden pages