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M29W640DTSTN/a3450avai64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORY


M29W640DT ,64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORYAbsolute Maximum Ratings 20DC and AC PARAMETERS . 21Table 9. Operating and AC Measuremen ..
M29W640DT90N6 ,64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORYM29W640DTM29W640DB64 Mbit (8Mb x8 or 4Mb x16, Boot Block)3V Supply Flash Memory
M29W640DT-90N6 ,64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORYAbsolute Maximum Ratings . . . . . . . 19DC and AC PARAMETERS . 20Table 9. Operating and ..
M29W640DT-90N6 ,64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORYLogic Diagram . . 5Table 1. Signal Names . . 5Figure 3. TSOP Connections . . . ..
M29W640DT90N6E ,64 Mbit 8Mb x8 or 4Mb x16, Boot Block 3V Supply Flash MemoryFEATURES SUMMARY . . . . . 1Figure 1. Packages . . . . . . 1SUMMARY DESCRIPTION ..
M29W640FB60ZA6E , 64 Mbit (8Mb x8 or 4Mb x16, Page, Boot Block) 3V Supply Flash Memory
M51203FP , VOLTAGE COMPARATOR
M51203FP , VOLTAGE COMPARATOR
M51203FP , VOLTAGE COMPARATOR
M51204TL , VOLTAGE COMPARATOR 
M51206FP , VOLTAGE COMPARATOR 
M51391ASP , PAL/NTSC VIDEO CHROMA DEFLECTION


M29W640DT
64 MBIT (8MB X8 OR 4MB X16, BOOT BLOCK) 3V SUPPLY FLASH MEMORY
1/48
PRELIMINARY DATA

January 2003
M29W640DT
M29W640DB

64 Mbit (8Mb x8 or 4Mb x16, Boot Block)
3V Supply Flash Memory
FEATURES SUMMARY
SUPPLY VOLTAGE
–VCC= 2.7V to 3.6V for Program, Erase, Read
–VPP =12 V for Fast Program (optional) ACCESS TIME: 70, 90ns PROGRAMMING TIME10 μs per Byte/Word typical Double Word Programming Option 135 MEMORY BLOCKS 1 Boot Block and 7 Parameter Blocks, KBytes each (Top or Bottom Location) 127 Main Blocks, 64 KBytes each PROGRAM/ERASE CONTROLLER Embedded Byte/Word Program algorithms ERASE SUSPEND and RESUME MODES Read and Program another Block during
Erase Suspend UNLOCK BYPASS PROGRAM COMMAND Faster Production/Batch Programming VPP/WP Pin for FAST PROGRAM and WRITE
PROTECT TEMPORARY BLOCK UNPROTECTION
MODE COMMON FLASH INTERFACE 64-bit Security Code EXTENDED MEMORY BLOCK Extra block used as security block or to store
additional information LOW POWER CONSUMPTION Standby and Automatic Standby 100,000 PROGRAM/ERASE CYCLES per
BLOCK ELECTRONIC SIGNATURE Manufacturer Code: 0020h Top Device Code M29W640DT: 22DEh Bottom Device Code M29W640DB: 22DFh
Figure 1. Packages
M29W640DT, M29W640DB
TABLE OF CONTENTS
SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Figure 2. Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Table 1. Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Figure 3. TSOP Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Figure 4. TFBGA Connections (Top view through package). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
SIGNAL DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Address Inputs (A0-A21). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Data Inputs/Outputs (DQ0-DQ7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Data Inputs/Outputs (DQ8-DQ14). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Data Input/Output or Address Input (DQ15A–1).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Chip Enable (E). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Output Enable (G). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Write Enable (W). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
VPP/Write Protect (VPP/WP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Reset/Block Temporary Unprotect (RP).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Ready/Busy Output (RB). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Byte/Word Organization Select (BYTE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
VCC Supply Voltage (2.7V to 3.6V).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
VSS Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
BUS OPERATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Bus Read. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Bus Write. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Output Disable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Standby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Automatic Standby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Special Bus Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Electronic Signature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Block Protect and Chip Unprotect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Block Protect and Chip Unprotect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Table 2. Bus Operations, BYTE = VIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Table 3. Bus Operations, BYTE = VIH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
COMMAND INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Read/Reset Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Auto Select Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Program Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Unlock Bypass Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Unlock Bypass Program Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Unlock Bypass Reset Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Chip Erase Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Block Erase Command.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
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M29W640DT, M29W640DB

Erase Suspend Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Erase Resume Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Enter Extended Block Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Exit Extended Block Command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Table 4. Commands, 16-bit mode, BYTE = VIH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Table 5. Commands, 8-bit mode, BYTE = VIL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Table 6. Program, Erase Times and Program, Erase Endurance Cycles . . . . . . . . . . . . . . . . . . . .17
STATUS REGISTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Data Polling Bit (DQ7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Toggle Bit (DQ6).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Error Bit (DQ5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Erase Timer Bit (DQ3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Alternative Toggle Bit (DQ2).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Table 7. Status Register Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Figure 5. Data Polling Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Figure 6. Data Toggle Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Table 8. Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
DC and AC PARAMETERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Table 9. Operating and AC Measurement Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Figure 7. AC Measurement I/O Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Figure 8. AC Measurement Load Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Table 10. Device Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Table 11. DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Figure 9. Read Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Table 12. Read AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Figure 10. Write AC Waveforms, Write Enable Controlled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Table 13. Write AC Characteristics, Write Enable Controlled . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Figure 11. Write AC Waveforms, Chip Enable Controlled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Table 14. Write AC Characteristics, Chip Enable Controlled . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Figure 12. Reset/Block Temporary Unprotect AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Table 15. Reset/Block Temporary Unprotect AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . .26
Figure 13. Accelerated Program Timing Waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
PACKAGE MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

TSOP48 – 48 lead Plastic Thin Small Outline, 12 x 20mm, Package Outline . . . . . . . . . . . . . . . .27
TSOP48 – 48 lead Plastic Thin Small Outline, 12 x 20mm, Package Mechanical Data . . . . . . . .27
TFBGA63 – 63 ball array, 0.8 mm pitch, Package Outline, Bottom view . . . . . . . . . . . . . . . . . . . .28
TFBGA63 – 63 ball array, 0.8 mm pitch, Package Mechanical Data . . . . . . . . . . . . . . . . . . . . . . .28
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Table 16. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
M29W640DT, M29W640DB
REVISION HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Table 26. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
APPENDIX A. BLOCK ADDRESSES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Table 17. Top Boot Block Addresses, M29W640DT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Table 18. Bottom Boot Block Addresses, M29W640DB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
APPENDIX B. COMMON FLASH INTERFACE (CFI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Table 19. Query Structure Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Table 20. CFI Query Identification String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Table 21. CFI Query System Interface Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Table 22. Device Geometry Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Table 23. Primary Algorithm-Specific Extended Query Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Table 24. Security Code Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
APPENDIX C. BLOCK PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Programmer Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
In-System Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Table 25. Programmer Technique Bus Operations, BYTE = VIH or VIL . . . . . . . . . . . . . . . . . . . . .42
Figure 14. Programmer Equipment Group Protect Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Figure 15. Programmer Equipment Chip Unprotect Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Figure 16. In-System Equipment Group Protect Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Figure 17. In-System Equipment Chip Unprotect Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
5/48
M29W640DT, M29W640DB
SUMMARY DESCRIPTION

The M29W640D is a 64 Mbit (8Mb x8 or 4Mb x16)
non-volatile memory that can be read, erased and
reprogrammed. These operations can be per-
formed using a single low voltage (2.7 to 3.6V)
supply. On power-up the memory defaults to its
Read mode where it can be read in the same way
as a ROM or EPROM.
The memory is divided into blocks that can be
erased independently so it is possible to preserve
valid data while old data is erased. Blocks can be
protected in units of 256 KByte (generally groups
of four 64 KByte sectors), to prevent accidental
Program or Erase commands from modifying the
memory. Program and Erase commands are writ-
ten to the Command Interface of the memory. An
on-chip Program/Erase Controller simplifies the
process of programming or erasing the memory by
taking care of all of the special operations that are
required to update the memory contents. The end
of a program or erase operation can be detected
and any error conditions identified. The command
set required to control the memory is consistent
with JEDEC standards.
The device features an asymmetrical blocked ar-
chitecture. The device has an array of 135 blocks: 8 Parameters Blocks of 8 KByte each (or KWord each) 127 Main Blocks of 64 KByte each (or 32 KWord
each)
M29W640DT has the Parameter Blocks at the top
of the memory address space while the
M29W640DB locates the Parameter Blocks start-
ing from the bottom.
Chip Enable, Output Enable and Write Enable sig-
nals control the bus operation of the memory.
They allow simple connection to most micropro-
cessors, often without additional logic.
The VPP/WP signal is used to enable faster pro-
gramming of the device, enabling double word
programming. If this signal is held at VSS, the boot
block, and its adjacent parameter block, are pro-
tected from program and erase operations.
The memory is delivered with all the bits erased (set
to 1).
Figure 2. Logic Diagram
Table 1. Signal Names
M29W640DT, M29W640DB
Figure 3. TSOP Connections
7/48
M29W640DT, M29W640DB
Figure 4. TFBGA Connections (Top view through package)

Note:1. Balls are shorted together via the substrate but not connected to the die.
M29W640DT, M29W640DB
SIGNAL DESCRIPTIONS

See Figure 2, Logic Diagram, and Table 1, Signal
Names, for a brief overview of the signals connect-
ed to this device.
Address Inputs (A0-A21).
The Address Inputs
select the cells in the memory array to access dur-
ing Bus Read operations. During Bus Write opera-
tions they control the commands sent to the
Command Interface of the internal state machine.
Data Inputs/Outputs (DQ0-DQ7).
The Data I/O
outputs the data stored at the selected address
during a Bus Read operation. During Bus Write
operations they represent the commands sent to
the Command Interface of the internal state ma-
chine.
Data Inputs/Outputs (DQ8-DQ14).
The Data I/O
outputs the data stored at the selected address
during a Bus Read operation when BYTE is High,
VIH. When BYTE is Low, VIL, these pins are not
used and are high impedance. During Bus Write
operations the Command Register does not use
these bits. When reading the Status Register
these bits should be ignored.
Data Input/Output or Address Input (DQ15A–1).

When BYTE is High, VIH, this pin behaves as a
Data Input/Output pin (as DQ8-DQ14). When
BYTE is Low, VIL, this pin behaves as an address
pin; DQ15A–1 Low will select the LSB of the ad-
dressed Word, DQ15A–1 High will select the MSB.
Throughout the text consider references to the
Data Input/Output to include this pin when BYTE is
High and references to the Address Inputs to in-
clude this pin when BYTE is Low except when
stated explicitly otherwise.
Chip Enable (E).
The Chip Enable, E, activates
the memory, allowing Bus Read and Bus Write op-
erations to be performed. When Chip Enable is
High, VIH, all other pins are ignored.
Output Enable (G).
The Output Enable, G, con-
trols the Bus Read operation of the memory.
Write Enable (W).
The Write Enable, W, controls
the Bus Write operation of the memory’s Com-
mand Interface.
VPP/Write Protect (VPP/WP).
The VPP/Write
Protect pin provides two functions. The VPP func-
tion allows the memory to use an external high
voltage power supply to reduce the time required
for Unlock Bypass Program operations. The
Write Protect function provides a hardware meth-
od of protecting the two outermost boot blocks.
The VPP/Write Protect pin must not be left floating
or unconnected.
When VPP/Write Protect is Low, VIL, the memory
protects the two outermost boot blocks; Program
and Erase operations in this block are ignored
while VPP/Write Protect is Low.
When VPP/Write Protect is High, VIH, the memory
reverts to the previous protection status of the two
outermost boot blocks. Program and Erase opera-
tions can now modify the data in the two outermost
boot blocks unless the block is protected using
Block Protection.
When VPP/Write Protect is raised to VPP the mem-
ory automatically enters the Unlock Bypass mode.
When VPP/Write Protect returns to VIH or VIL nor-
mal operation resumes. During Unlock Bypass
Program operations the memory draws IPP from
the pin to supply the programming circuits. See the
description of the Unlock Bypass command in the
Command Interface section. The transitions from
VIH to VPP and from VPP to VIH must be slower
than tVHVPP, see Figure 13.
Never raise VPP/Write Protect to VPP from any
mode except Read mode, otherwise the memory
may be left in an indeterminate state.
A 0.1μF capacitor should be connected between
the VPP/Write Protect pin and the VSS Ground pin
to decouple the current surges from the power
supply. The PCB track widths must be sufficient to
carry the currents required during Unlock Bypass
Program, IPP.
Reset/Block Temporary Unprotect (RP).
The
Reset/Block Temporary Unprotect pin can be
used to apply a Hardware Reset to the memory or
to temporarily unprotect all Blocks that have been
protected.
Note that if VPP/WP is at VIL, then the two outer-
most boot blocks will remain protected even if RP
is at VID.
A Hardware Reset is achieved by holding Reset/
Block Temporary Unprotect Low, VIL, for at least
tPLPX. After Reset/Block Temporary Unprotect
goes High, VIH, the memory will be ready for Bus
Read and Bus Write operations after tPHEL or
tRHEL, whichever occurs last. See the Ready/Busy
Output section, Table 15 and Figure 12, Reset/
Block Temporary Unprotect AC Characteristics,
for more details.
Holding RP at VID will temporarily unprotect the
protected Blocks in the memory. Program and
Erase operations on all blocks will be possible.
The transition from VIH to VID must be slower than
tPHPHH.
Ready/Busy Output (RB).
The Ready/Busy pin
is an open-drain output that can be used to identify
when the device is performing a Program or Erase
operation. During Program or Erase operations
Ready/Busy is Low, VOL. Ready/Busy is high-im-
pedance during Read mode, Auto Select mode
and Erase Suspend mode.
After a Hardware Reset, Bus Read and Bus Write
operations cannot begin until Ready/Busy be-
9/48
M29W640DT, M29W640DB

comes high-impedance. See Table 15 and Figure
12, Reset/Block Temporary Unprotect AC Charac-
teristics.
The use of an open-drain output allows the Ready/
Busy pins from several memories to be connected
to a single pull-up resistor. A Low will then indicate
that one, or more, of the memories is busy.
Byte/Word Organization Select (BYTE).
The
Byte/Word Organization Select pin is used to
switch between the x8 and x16 Bus modes of the
memory. When Byte/Word Organization Select is
Low, VIL, the memory is in x8 mode, when it is
High, VIH, the memory is in x16 mode.
VCC Supply Voltage (2.7V to 3.6V).
VCC pro-
vides the power supply for all operations (Read,
Program and Erase).
The Command Interface is disabled when the VCC
Supply Voltage is less than the Lockout Voltage,
VLKO. This prevents Bus Write operations from ac-
cidentally damaging the data during power up,
power down and power surges. If the Program/
Erase Controller is programming or erasing during
this time then the operation aborts and the memo-
ry contents being altered will be invalid.
A 0.1μF capacitor should be connected between
the VCC Supply Voltage pin and the VSS Ground
pin to decouple the current surges from the power
supply. The PCB track widths must be sufficient to
carry the currents required during Program and
Erase operations, ICC3.
VSS Ground.
VSS is the reference for all voltage
measurements.
M29W640DT, M29W640DB
BUS OPERATIONS

There are five standard bus operations that control
the device. These are Bus Read, Bus Write, Out-
put Disable, Standby and Automatic Standby. See
Table 2 and Table 3, Bus Operations, for a sum-
mary. Typically glitches of less than 5ns on Chip
Enable or Write Enable are ignored by the memory
and do not affect bus operations.
Bus Read.
Bus Read operations read from the
memory cells, or specific registers in the Com-
mand Interface. A valid Bus Read operation in-
volves setting the desired address on the Address
Inputs, applying a Low signal, VIL, to Chip Enable
and Output Enable and keeping Write Enable
High, VIH. The Data Inputs/Outputs will output the
value, see Figure 9, Read Mode AC Waveforms,
and Table 12, Read AC Characteristics, for details
of when the output becomes valid.
Bus Write.
Bus Write operations write to the
Command Interface. A valid Bus Write operation
begins by setting the desired address on the Ad-
dress Inputs. The Address Inputs are latched by
the Command Interface on the falling edge of Chip
Enable or Write Enable, whichever occurs last.
The Data Inputs/Outputs are latched by the Com-
mand Interface on the rising edge of Chip Enable
or Write Enable, whichever occurs first. Output En-
able must remain High, VIH, during the whole Bus
Write operation. See Figure 10 and Figure 11,
Write AC Waveforms, and Table 13 and Table 14,
Write AC Characteristics, for details of the timing
requirements.
Output Disable.
The Data Inputs/Outputs are in
the high impedance state when Output Enable is
High, VIH.
Standby.
When Chip Enable is High, VIH, the
memory enters Standby mode and the Data In-
puts/Outputs pins are placed in the high-imped-
ance state. To reduce the Supply Current to the
Standby Supply Current, ICC2, Chip Enable should
be held within VCC ± 0.2V. For the Standby current
level see Table 11, DC Characteristics.
During program or erase operations the memory
will continue to use the Program/Erase Supply
Current, ICC3, for Program or Erase operations un-
til the operation completes.
Automatic Standby.
If CMOS levels (VCC ± 0.2V)
are used to drive the bus and the bus is inactive for
300ns or more the memory enters Automatic
Standby where the internal Supply Current is re-
duced to the Standby Supply Current, ICC2. The
Data Inputs/Outputs will still output data if a Bus
Read operation is in progress.
Special Bus Operations

Additional bus operations can be performed to
read the Electronic Signature and also to apply
and remove Block Protection. These bus opera-
tions are intended for use by programming equip-
ment and are not usually used in applications.
They require VID to be applied to some pins.
Electronic Signature.
The memory has two
codes, the manufacturer code and the device
code, that can be read to identify the memory.
These codes can be read by applying the signals
listed in Table 2 and Table 3, Bus Operations. lock P rotect andChip U nprotect. Groups of
blocks can be protected against accidental Pro-
gram or Erase. The Protection Groups are shown
in Appendix A, Table 17 and Table 18, Block Ad-
dresses. The whole chip can be unprotected to al-
low the data inside the blocks to be changed.
The VPP/Write Protect pin can be used to protect
the two outermost boot blocks. When VPP/Write
Protect is at VIL the two outermost boot blocks are
protected and remain protected regardless of the
Block Protection Status or the Reset/Block Tem-
porary Unprotect pin status.
Block Protect and Chip Unprotect operations are
described in Appendix C.
11/48
M29W640DT, M29W640DB
Table 2. Bus Operations, BYTE = VIL

Note: X = VIL or VIH.
Table 3. Bus Operations, BYTE = VIH

Note: X = VIL or VIH.
M29W640DT, M29W640DB
COMMAND INTERFACE

All Bus Write operations to the memory are inter-
preted by the Command Interface. Commands
consist of one or more sequential Bus Write oper-
ations. Failure to observe a valid sequence of Bus
Write operations will result in the memory return-
ing to Read mode. The long command sequences
are imposed to maximize data security.
The address used for the commands changes de-
pending on whether the memory is in 16-bit or 8-
bit mode. See either Table 4, or Table 5, depend-
ing on the configuration that is being used, for a
summary of the commands.
Read/Reset Command.

The Read/Reset command returns the memory to
its Read mode where it behaves like a ROM or
EPROM. It also resets the errors in the Status
Register. Either one or three Bus Write operations
can be used to issue the Read/Reset command.
The Read/Reset command can be issued, be-
tween Bus Write cycles before the start of a pro-
gram or erase operation, to return the device to
read mode. If the Read/Reset command is issued
during the timeout of a Block erase operation then
the memory will take up to 10μs to abort. During
the abort period no valid data can be read from the
memory. The Read/Reset command will not abort
an Erase operation when issued while in Erase
Suspend.
Auto Select Command.

The Auto Select command is used to read the
Manufacturer Code, the Device Code and the
Block Protection Status. Three consecutive Bus
Write operations are required to issue the Auto Se-
lect command. Once the Auto Select command is
issued the memory remains in Auto Select mode
until a Read/Reset command is issued. Read CFI
Query and Read/Reset commands are accepted
in Auto Select mode, all other commands are ig-
nored.
In Auto Select mode the Manufacturer Code can
be read using a Bus Read operation with A0 = VIL
and A1 = VIL. The other address bits may be set to
either VIL or VIH. The Manufacturer Code for ST-
Microelectronics is 0020h.
The Device Code can be read using a Bus Read
operation with A0 = VIH and A1 = VIL. The other
address bits may be set to either VIL or VIH. The
Device Code for the M29W640DT is 22DEh and
for the M29W640DB is 22DFh.
The Block Protection Status of each block can be
read using a Bus Read operation with A0 = VIL,= VIH, and A12-A21 specifying the address of
the block. The other address bits may be set to ei-
ther VIL or VIH. If the addressed block is protected
then 01h is output on Data Inputs/Outputs DQ0-
DQ7, otherwise 00h is output.
Read CFI Query Command.

The Read CFI Query Command is used to read
data from the Common Flash Interface (CFI)
Memory Area. This command is valid when the de-
vice is in the Read Array mode, or when the device
is in Autoselected mode.
One Bus Write cycle is required to issue the Read
CFI Query Command. Once the command is is-
sued subsequent Bus Read operations read from
the Common Flash Interface Memory Area.
The Read/Reset command must be issued to re-
turn the device to the previous mode (the Read Ar-
ray mode or Autoselected mode). A second Read/
Reset command would be needed if the device is
to be put in the Read Array mode from Autoselect-
ed mode.
See Appendix B, Table 19 to Table 24 for details
on the information contained in the Common Flash
Interface (CFI) memory area.
Program Command.

The Program command can be used to program a
value to one address in the memory array at a
time. The command requires four Bus Write oper-
ations, the final write operation latches the ad-
dress and data in the internal state machine and
starts the Program/Erase Controller.
If the address falls in a protected block then the
Program command is ignored, the data remains
unchanged. The Status Register is never read and
no error condition is given.
During the program operation the memory will ig-
nore all commands. It is not possible to issue any
command to abort or pause the operation. Typical
program times are given in Table 6. Bus Read op-
erations during the program operation will output
the Status Register on the Data Inputs/Outputs.
See the section on the Status Register for more
details.
After the program operation has completed the
memory will return to the Read mode, unless an
error has occurred. When an error occurs the
memory will continue to output the Status Regis-
ter. A Read/Reset command must be issued to re-
set the error condition and return to Read mode.
Note that the Program command cannot change a
bit set at ’0’ back to ’1’. One of the Erase Com-
mands must be used to set all the bits in a block or
in the whole memory from ’0’ to ’1’.
Fast Program Commands

There are two Fast Program commands available
to improve the programming throughput, by writing
several adjacent words or bytes in parallel. The
Quadruple Byte Program command is available for
x8 operations, while the Double Word Program
command is available for x16 operations.
13/48
M29W640DT, M29W640DB
Quadruple Byte Program Command.
The Qua-
druple Byte Program command is used to write a
page of four adjacent Bytes in parallel. The four
bytes must differ only for addresses A0, DQ15A-1.
Five bus write cycles are necessary to issue the
Quadruple Byte Program command. The first bus cycle sets up the Quadruple Byte
Program Command. The second bus cycle latches the Address and
the Data of the first byte to be written. The third bus cycle latches the Address and the
Data of the second byte to be written. The fourth bus cycle latches the Address and
the Data of the third byte to be written. The fifth bus cycle latches the Address and the
Data of the fourth byte to be written and starts
the Program/Erase Controller.
Double Word Program Command.
The Double
Word Program command is used to write a page
of two adjacent words in parallel. The two words
must differ only for the address A0.
Three bus write cycles are necessary to issue the
Double Word Program command. The first bus cycle sets up the Double Word
Program Command. The second bus cycle latches the Address and
the Data of the first word to be written. The third bus cycle latches the Address and the
Data of the second word to be written and starts
the Program/Erase Controller.
Only one bank can be programmed at any one
time. The other bank must be in Read mode or
Erase Suspend.
Programming should not be attempted when VPP
is not at VPPH.
After programming has started, Bus Read opera-
tions in the Bank being programmed output the
Status Register content, while Bus Read opera-
tions to the other Bank output the contents of the
memory array.
After the program operation has completed the
memory will return to the Read mode, unless an
error has occurred. When an error occurs Bus
Read operations to the Bank where the command
was issued will continue to output the Status Reg-
ister. A Read/Reset command must be issued to
reset the error condition and return to Read mode.
Note that the Fast Program commands cannot
change a bit set at ’0’ back to ’1’. One of the Erase
Commands must be used to set all the bits in a
block or in the whole memory from ’0’ to ’1’.
Typical Program times are given in Table 6, Pro-
gram, Erase Times and Program, Erase Endur-
ance Cycles.
Unlock Bypass Command.

The Unlock Bypass command is used in conjunc-
tion with the Unlock Bypass Program command to
program the memory faster than with the standard
program commands. When the cycle time to the
device is long (as with some EPROM program-
mers) considerable time saving can be made by
using these commands. Three Bus Write opera-
tions are required to issue the Unlock Bypass
command.
Once the Unlock Bypass command has been is-
sued the memory will only accept the Unlock By-
pass Program command and the Unlock Bypass
Reset command. The memory can be read as if in
Read mode.
When VPP is applied to the VPP/Write Protect pin
the memory automatically enters the Unlock By-
pass mode and the Unlock Bypass Program com-
mand can be issued immediately.
Unlock Bypass Program Command.

The Unlock Bypass command is used in conjunc-
tion with the Unlock Bypass Program command to
program the memory. When the cycle time to the
device is long (as with some EPROM program-
mers) considerable time saving can be made by
using these commands. Three Bus Write opera-
tions are required to issue the Unlock Bypass
command.
Once the Unlock Bypass command has been is-
sued the memory will only accept the Unlock By-
pass Program command and the Unlock Bypass
Reset command. The memory can be read as if in
Read mode.
The memory offers accelerated program opera-
tions through the VPP/Write Protect pin. When the
system asserts VPP on the VPP/Write Protect pin,
the memory automatically enters the Unlock By-
pass mode. The system may then write the two-
cycle Unlock Bypass program command se-
quence. The memory uses the higher voltage on
the VPP/Write Protect pin, to accelerate the Unlock
Bypass Program operation.
Never raise VPP/Write Protect to VPP from any
mode except Read mode, otherwise the memory
may be left in an indeterminate state.
Unlock Bypass Reset Command.

The Unlock Bypass Reset command can be used
to return to Read/Reset mode from Unlock Bypass
Mode. Two Bus Write operations are required to
issue the Unlock Bypass Reset command. Read/
Reset command does not exit from Unlock Bypass
Mode.
Chip Erase Command.

The Chip Erase command can be used to erase
the entire chip. Six Bus Write operations are re-
M29W640DT, M29W640DB
quired to issue the Chip Erase Command and start
the Program/Erase Controller.
If any blocks are protected then these are ignored
and all the other blocks are erased. If all of the
blocks are protected the Chip Erase operation ap-
pears to start but will terminate within about 100μs,
leaving the data unchanged. No error condition is
given when protected blocks are ignored.
During the erase operation the memory will ignore
all commands, including the Erase Suspend com-
mand. It is not possible to issue any command to
abort the operation. Typical chip erase times are
given in Table 6. All Bus Read operations during
the Chip Erase operation will output the Status
Register on the Data Inputs/Outputs. See the sec-
tion on the Status Register for more details.
After the Chip Erase operation has completed the
memory will return to the Read Mode, unless an
error has occurred. When an error occurs the
memory will continue to output the Status Regis-
ter. A Read/Reset command must be issued to re-
set the error condition and return to Read Mode.
The Chip Erase Command sets all of the bits in un-
protected blocks of the memory to ’1’. All previous
data is lost.
Block Erase Command.

The Block Erase command can be used to erase
a list of one or more blocks. Six Bus Write opera-
tions are required to select the first block in the list.
Each additional block in the list can be selected by
repeating the sixth Bus Write operation using the
address of the additional block. The Block Erase
operation starts the Program/Erase Controller
about 50μs after the last Bus Write operation.
Once the Program/Erase Controller starts it is not
possible to select any more blocks. Each addition-
al block must therefore be selected within 50μs of
the last block. The 50μs timer restarts when an ad-
ditional block is selected. The Status Register can
be read after the sixth Bus Write operation. See
the Status Register section for details on how to
identify if the Program/Erase Controller has start-
ed the Block Erase operation.
If any selected blocks are protected then these are
ignored and all the other selected blocks are
erased. If all of the selected blocks are protected
the Block Erase operation appears to start but will
terminate within about 100μs, leaving the data un-
changed. No error condition is given when protect-
ed blocks are ignored.
During the Block Erase operation the memory will
ignore all commands except the Erase Suspend
command. Typical block erase times are given in
Table 6. All Bus Read operations during the Block
Erase operation will output the Status Register on
the Data Inputs/Outputs. See the section on the
Status Register for more details.
After the Block Erase operation has completed the
memory will return to the Read Mode, unless an
error has occurred. When an error occurs the
memory will continue to output the Status Regis-
ter. A Read/Reset command must be issued to re-
set the error condition and return to Read mode.
The Block Erase Command sets all of the bits in
the unprotected selected blocks to ’1’. All previous
data in the selected blocks is lost.
Erase Suspend Command.

The Erase Suspend Command may be used to
temporarily suspend a Block Erase operation and
return the memory to Read mode. The command
requires one Bus Write operation.
The Program/Erase Controller will suspend within μs of the Erase Suspend Command being is-
sued. Once the Program/Erase Controller has
stopped the memory will be set to Read mode and
the Erase will be suspended. If the Erase Suspend
command is issued during the period when the
memory is waiting for an additional block (before
the Program/Erase Controller starts) then the
Erase is suspended immediately and will start im-
mediately when the Erase Resume Command is
issued. It is not possible to select any further
blocks to erase after the Erase Resume.
During Erase Suspend it is possible to Read and
Program cells in blocks that are not being erased;
both Read and Program operations behave as
normal on these blocks. If any attempt is made to
program in a protected block or in the suspended
block then the Program command is ignored and
the data remains unchanged. The Status Register
is not read and no error condition is given. Read-
ing from blocks that are being erased will output
the Status Register.
It is also possible to issue the Auto Select, Read
CFI Query and Unlock Bypass commands during
an Erase Suspend. The Read/Reset command
must be issued to return the device to Read Array
mode before the Resume command will be ac-
cepted.
Erase Resume Command.

The Erase Resume command must be used to re-
start the Program/Erase Controller after an Erase
Suspend. The device must be in Read Array mode
before the Resume command will be accepted. An
erase can be suspended and resumed more than
once.
Enter Extended Block Command

The device has an extra 64 KByte block (Extended
Block) that can only be accessed using the Enter
Extended Block command. Three Bus write cycles
are required to issue the Extended Block com-
mand. Once the command has been issued the
device enters Extended Block mode where all Bus
Read or Write operations to the Boot Block ad-
15/48
M29W640DT, M29W640DB

dresses access the Extended Block. The Extend-
ed Block (with the same address as the Boot
Blocks) cannot be erased, and can be treated as
one-time programmable (OTP) memory. In Ex-
tended Block mode the Boot Blocks are not ac-
cessible.
To exit from the Extended Block mode the Exit Ex-
tended Block command must be issued.
The Extended Block can be protected, however
once protected the protection cannot be undone.
Exit Extended Block Command.

The Exit Extended Block command is used to exit
from the Extended Block mode and return the de-
vice to Read mode. Four Bus Write operations are
required to issue the command.
Block Protect and Chip Unprotect Commands.

Groups of blocks can be protected against acci-
dental Program or Erase. The Protection Groups
are shown in Appendix A, Table 17 and Table 18,
Block Addresses. The whole chip can be unpro-
tected to allow the data inside the blocks to be
changed.
Block Protect and Chip Unprotect operations are
described in Appendix C.
M29W640DT, M29W640DB
Table 4. Commands, 16-bit mode, BYTE = VIH

Note: X Don’t Care, PA Program Address, PD Program Data, BA Any address in the Block. All values in the table are in hexadecimal.
The Command Interface only uses A–1, A0-A10 and DQ0-DQ7 to verify the commands; A11-A20, DQ8-DQ14 and DQ15 are Don’t
Care. DQ15A–1 is A–1 when BYTE is VIL or DQ15 when BYTE is VIH.
17/48
M29W640DT, M29W640DB
Table 5. Commands, 8-bit mode, BYTE = VIL

Note: X Don’t Care, PA Program Address, PD Program Data, BA Any address in the Block. All values in the table are in hexadecimal.
The Command Interface only uses A–1, A0-A10 and DQ0-DQ7 to verify the commands; A11-A20, DQ8-DQ14 and DQ15 are Don’t
Care. DQ15A–1 is A–1 when BYTE is VIL or DQ15 when BYTE is VIH.
Table 6. Program, Erase Times and Program, Erase Endurance Cycles

Note:1. TA = 25°C, VCC = 3.3V.
M29W640DT, M29W640DB
STATUS REGISTER

Bus Read operations from any address always
read the Status Register during Program and
Erase operations. It is also read during Erase Sus-
pend when an address within a block being erased
is accessed.
The bits in the Status Register are summarized in
Table 7, Status Register Bits.
Data Polling Bit (DQ7).
The Data Polling Bit can
be used to identify whether the Program/Erase
Controller has successfully completed its opera-
tion or if it has responded to an Erase Suspend.
The Data Polling Bit is output on DQ7 when the
Status Register is read.
During Program operations the Data Polling Bit
outputs the complement of the bit being pro-
grammed to DQ7. After successful completion of
the Program operation the memory returns to
Read mode and Bus Read operations from the ad-
dress just programmed output DQ7, not its com-
plement.
During Erase operations the Data Polling Bit out-
puts ’0’, the complement of the erased state of
DQ7. After successful completion of the Erase op-
eration the memory returns to Read Mode.
In Erase Suspend mode the Data Polling Bit will
output a ’1’ during a Bus Read operation within a
block being erased. The Data Polling Bit will
change from a ’0’ to a ’1’ when the Program/Erase
Controller has suspended the Erase operation.
Figure 5, Data Polling Flowchart, gives an exam-
ple of how to use the Data Polling Bit. A Valid Ad-
dress is the address being programmed or an
address within the block being erased.
Toggle Bit (DQ6).
The Toggle Bit can be used to
identify whether the Program/Erase Controller has
successfully completed its operation or if it has re-
sponded to an Erase Suspend. The Toggle Bit is
output on DQ6 when the Status Register is read.
During Program and Erase operations the Toggle
Bit changes from ’0’ to ’1’ to ’0’, etc., with succes-
sive Bus Read operations at any address. After
successful completion of the operation the memo-
ry returns to Read mode.
During Erase Suspend mode the Toggle Bit will
output when addressing a cell within a block being
erased. The Toggle Bit will stop toggling when the
Program/Erase Controller has suspended the
Erase operation.
Figure 6, Data Toggle Flowchart, gives an exam-
ple of how to use the Data Toggle Bit.
Error Bit (DQ5).
The Error Bit can be used to
identify errors detected by the Program/Erase
Controller. The Error Bit is set to ’1’ when a Pro-
gram, Block Erase or Chip Erase operation fails to
write the correct data to the memory. If the Error
Bit is set a Read/Reset command must be issued
before other commands are issued. The Error bit
is output on DQ5 when the Status Register is read.
Note that the Program command cannot change a
bit set to ’0’ back to ’1’ and attempting to do so will
set DQ5 to ‘1’. A Bus Read operation to that ad-
dress will show the bit is still ‘0’. One of the Erase
commands must be used to set all the bits in a
block or in the whole memory from ’0’ to ’1’.
Erase Timer Bit (DQ3).
The Erase Timer Bit can
be used to identify the start of Program/Erase
Controller operation during a Block Erase com-
mand. Once the Program/Erase Controller starts
erasing the Erase Timer Bit is set to ’1’. Before the
Program/Erase Controller starts the Erase Timer
Bit is set to ’0’ and additional blocks to be erased
may be written to the Command Interface. The
Erase Timer Bit is output on DQ3 when the Status
Register is read.
Alternative Toggle Bit (DQ2).
The Alternative
Toggle Bit can be used to monitor the Program/
Erase controller during Erase operations. The Al-
ternative Toggle Bit is output on DQ2 when the
Status Register is read.
During Chip Erase and Block Erase operations the
Toggle Bit changes from ’0’ to ’1’ to ’0’, etc., with
successive Bus Read operations from addresses
within the blocks being erased. A protected block
is treated the same as a block not being erased.
Once the operation completes the memory returns
to Read mode.
During Erase Suspend the Alternative Toggle Bit
changes from ’0’ to ’1’ to ’0’, etc. with successive
Bus Read operations from addresses within the
blocks being erased. Bus Read operations to ad-
dresses within blocks not being erased will output
the memory cell data as if in Read mode.
After an Erase operation that causes the Error Bit
to be set the Alternative Toggle Bit can be used to
identify which block or blocks have caused the er-
ror. The Alternative Toggle Bit changes from ’0’ to
’1’ to ’0’, etc. with successive Bus Read Opera-
tions from addresses within blocks that have not
erased correctly. The Alternative Toggle Bit does
not change if the addressed block has erased cor-
rectly.
19/48
M29W640DT, M29W640DB
Table 7. Status Register Bits

Note: Unspecified data bits should be ignored.
Figure 5. Data Polling Flowchart Figure 6. Data Toggle Flowchart
M29W640DT, M29W640DB
MAXIMUM RATING

Stressing the device above the rating listed in the
Absolute Maximum Ratings table may cause per-
manent damage to the device. Exposure to Abso-
lute Maximum Rating conditions for extended
periods may affect device reliability. These are
stress ratings only and operation of the device at
these or any other conditions above those indicat-
ed in the Operating sections of this specification is
not implied. Refer also to the STMicroelectronics
SURE Program and other relevant quality docu-
ments.
Table 8. Absolute Maximum Ratings

Note:1. Minimum voltage may undershoot to –2V during transition and for less than 20ns during transitions. Maximum voltage may overshoot to VCC +2V during transition and for less than 20ns during transitions. VPP must not remain at 12V for more than a total of 80hrs.
21/48
M29W640DT, M29W640DB
DC AND AC PARAMETERS

This section summarizes the operating and mea-
surement conditions, and the DC and AC charac-
teristics of the device. The parameters in the DC
and AC Characteristic tables that follow are de-
rived from tests performed under the Measure-
ment Conditions summarized in the relevant
tables. Designers should check that the operating
conditions in their circuit match the measurement
conditions when relying on the quoted parame-
ters.
Table 9. Operating and AC Measurement Conditions
Figure 7. AC Measurement I/O Waveform Figure 8. AC Measurement Load Circuit
Table 10. Device Capacitance

Note: Sampled only, not 100% tested.
M29W640DT, M29W640DB
Table 11. DC Characteristics

Note:1. Sampled only, not 100% tested.
23/48
M29W640DT, M29W640DB
Figure 9. Read Mode AC Waveforms
Table 12. Read AC Characteristics

Note:1. Sampled only, not 100% tested.
M29W640DT, M29W640DB
Figure 10. Write AC Waveforms, Write Enable Controlled
Table 13. Write AC Characteristics, Write Enable Controlled

Note:1. Sampled only, not 100% tested.
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