• Low VCC write inhibit is equal to or less than 2.3V
• Package type:
- 40-pin TSOP
- 32-pin PLCC
• Compatibility with JEDEC standard
- Pinout and software compatible with single-power
supply Flash
GENERAL DESCRIPTION
The MX29LV004T/B is a 4-mega bit Flash memory organized as 512K bytes of 8 bits. MXIC's Flash memories offer the most cost-effective and reliable read/write
non-volatile random access memory . The MX29L V004T/
B is packaged in 40-pin TSOP and 32-pin PLCC. It is
designed to be reprogrammed and erased in system or
in standard EPROM programmers.
The standard MX29L V004T/B off ers access time as fast
as 55ns, allowing operation of high-speed microprocessors without wait states. To eliminate bus contention,
the MX29L V004T/B has separate chip enab le (CE) and
output enable (OE) controls.
MXIC's Flash memories augment EPROM functionality
with in-circuit electrical erasure and programming. The
MX29LV004T/B uses a command register to manage
this functionality . The command register allo ws for 100%
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TTL level control inputs and fixed power supply levels
during erase and programming, while maintaining maximum EPROM compatibility.
MXIC Flash technology reliably stores memory contents
even after 100,000 erase and prog ram cycles. The MXIC
cell is designed to optimize the erase and programming
mechanisms. In addition, the combination of advanced
tunnel oxide processing and low internal electric fields
for erase and program operations produces reliable cycling. The MX29LV004T/B uses a 2.7V~3.6V VCC supply to perform the High Reliability Erase and auto Program/Erase algorithms.
The highest degree of latch-up protection is achieved
with MXIC's proprietary non-epi process. Latch-up protection is proved for stresses up to 100 milliamps on
address and data pin from -1V to VCC + 1V.
The MX29L V004T/B is byte programmab le using the Automatic Programming algorithm. The Automatic Programming algorithm makes the external system do not
need to have time out sequence nor to verify the data
programmed. The typical chip programming time at room
temperature of the MX29LV004T/B is less than 10 seconds.
AUTOMATIC CHIP ERASE
The entire chip is bulk erased using 10 ms erase pulses
according to MXIC's Automatic Chip Erase algorithm.
T ypical erasure at room temper ature is accomplished in
less than 25 second. The Automatic Erase algorithm
automatically programs the entire array prior to electrical erase. The timing and v erification of electrical erase
are controlled internally within the device.
AUTOMATIC SECTOR ERASE
The MX29L V004T/B is sector(s) erasab le using MXIC's
Auto Sector Erase algorithm. The Automatic Sector
Erase algorithm automatically programs the specified
sector(s) prior to electrical erase. The timing and verification of electrical erase are controlled internally within
the device. An erase operation can erase one sector,
multiple sectors, or the entire device.
AUTOMATIC PROGRAMMING ALGORITHM
MXIC's Automatic Programming algorithm requires the
user to only write program set-up commands (including
2 unlock write cycle and A0H) and a program command
(program data and address). The device automatically
times the programming pulse width, provides the program verification, and counts the number of sequences.
The device provides an unlock bypass mode with faster
programming. Only two write cycles are needed to program a byte, instead of f our. A status bit similar to D AT A
polling and a status bit toggling between consecutive
read cycles, provide feedback to the user as to the status of the programming operation. Refer to write operation status, table7, for more information on these status
bits.
AUTOMATIC ERASE ALGORITHM
MXIC's Automatic Erase algorithm requires the user to
write commands to the command register using standard microprocessor write timings. The device will automatically pre-program and verify the entire array. Then
the device automatically times the erase pulse width,
provides the erase verification, and counts the number
of sequences. A status bit toggling between consecutive read cycles provides feedback to the user as to the
status of the erasing operation.
Register contents serve as inputs to an internal statemachine which controls the erase and programming circuitry . During write cycles, the command register internally latches address and data needed for the programming and erase operations. During a system write cycle,
addresses are latched on the falling edge, and data are
latched on the rising edge of WE or CE, whichev er happens first.
MXIC's Flash technology combines years of EPROM
experience to produce the highest lev els of quality, reliability , and cost effectiv eness. The MX29LV004T/B electrically erases all bits simultaneously using FowlerNordheim tunneling. The bytes are prog rammed by using the EPROM programming mechanism of hot electron injection.
During a program cycle, the state-machine will control
the program sequences and command register will not
respond to any command set. During a Sector Erase
cycle, the command register will only respond to Erase
Suspend command. After Erase Suspend is completed,
the device stays in read mode. After the state machine
has completed its task, it will allow the command register to respond to its full command set.
AUTOMATIC SELECT
The automatic select mode provides manufacturer and
device identification, and sector protection verification,
through identifier codes output on Q7~Q0. This mode is
mainly adapted for programming equipment on the device to be programmed with its programming algorithm.
When programming by high voltage method, automatic
select mode requires VID (11.5V to 12.5V) on address
pin A9 and other address pin A6, A1 as referring to Table
3. In addition, to access the automatic select codes insystem, the host can issue the automatic select com-
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MX29LV004T/B
mand through the command register without requiring
VID , as sho wn in table4.
T o v erify whether or not sector being protected, the sector address must appear on the appropriate highest order address bit (see Table 1 and Table 2). The rest of
address bits, as shown in table3, are don't care. Once
all necessary bits have been set as required, the programming equipment may read the corresponding identifier code on Q7~Q0.
Note:
1 . ADI = Address of Device identifier; A1=0, A0 = 0 for manufacturer code,A1=0, A0 = 1 for device code. A2-A17=do
not care.
(Refer to table 3)
DDI = Data of Device identifier : C2H f or man uf acture code, B5H/B6H (Top/Bottom) for device code.
X = X can be VIL or VIH
RA=Address of memory location to be read.
RD=Data to be read at location RA.
2. P A = Address of memory location to be programmed.
PD = Data to be programmed at location PA.
SA = Address of the sector to be erased.
3. The system should generate the following address patterns: 555H or 2AAH to Address A11~A0.
Address bit A12~A18=X=Don't care for all address commands except f or Progr am Address (PA) and Sector
Address (SA). Write Sequence may be initiated with A12~A18 in either state .
4. For Sector Protect Verify operation:If read out data is 01H, it means the sector has been protected. If read out
data is 00H, it means the sector is still not being protected.
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7
COMMAND DEFINITIONS
MX29LV004T/B
Device operations are selected by writing specific address and data sequences into the command register.
Writing incorrect address and data values or writing them
sequences. Note that the Erase Suspend (B0H) and
Erase Resume (30H) commands are valid only while the
Sector Erase operation is in progress.
in the improper sequence will reset the device to the
read mode. Table 4 defines the valid register command
T ABLE 5. MX29LV004T/B BUS OPERA TION
ADDRESS Q8~Q15
DESCRIPTIONCEOE WE RESET A18 A12 A9 A8 A6 A5 A 1 A0Q0~Q7BYTEBYTE
(8)A 13 A10A7A2=VIH=VIL
ReadLLHHAINDoutDout Q8~Q14=High Z
Q15=A-1
WriteLHLHAINDIN(3)DIN Q8~Q14=High Z
Q15=A-1
ResetXXXLXHigh ZHigh ZHigh Z
Temproary sector unlockXXXVIDAINDI ND INHigh Z
Output DisableLHHHXHigh ZHigh ZHigh Z
StandbyVcc ±XXVcc±XHigh ZHigh ZHigh Z
1. Manufacturer and device codes may also be accessed via a command register write sequence. Refer to Table 4.
2. VID is the Silicon-ID-Read high voltage, 11.5V to 12.5V.
3. Refer to Table 4 for valid Data-In during a write operation.
4. X can be VIL or VIH.
5. Code=00H means unprotected.
Code=01H means protected.
6. A18~A13=Sector address for sector protect.
7. The sector protect and chip unprotect functions may also be implemented via programming equipment.
8. RESET pin for 40-TSOP package type only.
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REV. 1.1, SEP. 19, 2001
MX29LV004T/B
REQUIREMENTS FOR READING ARRAY
DATA
To read array data from the outputs, the system must
drive the CE and OE pins to VIL. CE is the pow er control
and selects the device. OE is the output control and gates
array data to the output pins. WE should remain at VIH.
The internal state machine is set for reading array data
upon device power-up, or after a hardware reset. This
ensures that no spurious alteration of the memory contect
occurs during the power transition. No command is
necessary in this mode to obtain array data. Standard
microprocessor read cycles that assert valid address on
the device address inputs produce valid data on the device
data outputs. The device remains enab led for read access
until the command register contents are altered.
WRITE COMMANDS/COMMAND
SEQUENCES
T o program data to the de vice or erase sectors of memory
, the sysytem must drive WE and CE to VIL, and OE to
VIH.
Refer to the Autoselect Mode and Autoselect Command
Sequence section for more information.
ICC2 in the DC Characteristics table represents the
active current specification for the write mode. The "A C
Characteristics" section contains timing specification
table and timing diagrams for write operations.
STANDBY MODE
When using both pins of CE and RESET, the device
enter CMOS Standby with both pins held at Vcc ± 0.3V.
The RESET pin is provided only for 40-pin TSOP package type. If CE and RESET are held at VIH, but not
within the range of V CC ± 0.3V , the de vice will still be in
the standby mode, but the standb y current will be larger.
During Auto Algorithm operation, Vcc active current
(Icc2) is required even CE = "H" until the operation is
complated. The device can be read with standard access time (tCE) from either of these standby modes,
before it is ready to read data.
OUTPUT DISABLE
The device features an Unlock Bypass mode to facilitate
faster programming. Once the device enters the Unlock
Bypass mode, only two write cycles are required to
program a byte, instead of four. The "byte Program
Command Sequence" section has details on
programming data to the device using both standard and
Unlock Bypass command sequences.
An erase operation can erase one sector , multiple sectors
, or the entire device. Table indicates the address space
that each sector occupies. A "sector address" consists
of the address bits required to uniquely select a sector.
The "Writing specific address and data commands or
sequences into the command register initiates device
operations. Table 1 defines the valid register command
sequences. Writing incorrect address and data values or
writing them in the improper sequence resets the device
to reading array data."section has details on erasing a
sector or the entire chip, or suspending/resuming the erase
operation.
After the system writes the autoselect command
sequence, the device enters the autoselect mode. The
system can then read autoselect codes from the internal
reqister (which is separate from the memory array) on
Q7-Q0. Standard read cycle timings apply in this mode.
With the OE input at a logic high level (VIH), output from
the devices are disabled. This will cause the output pins
to be in a high impedance state.
RESET OPERATION (for 40-TSOP package type)
The RESET pin provides a hardware method of resetting
the device to reading arra y data. When the RESET pin is
driven low for at least a period of tRP, the device
immediately terminates any operation in progress,
tristates all output pins, and ignores all read/write
commands for the duration of the RESET pluse. The
device also resets the internal state machine to reading
array data. The operation that was interrupted should be
reinitated once the device is ready to accept another
command sequence, to ensure data integrity
Current is reduced for the duration of the RESET pulse.
When RESET is held at VSS±0.3V, the device draws
CMOS standby current (ICC4). If RESET is held at VIL
but not within VSS±0.3V, the standby current will be
greater.
The RESET pin may be tied to system reset circuitry . A
system reset would that also reset the Flash memory ,
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9
MX29LV004T/B
enabling the system to read the boot-up firm-ware from
the Flash memory .
If RESET is asserted during a program or erase
operation, the R Y/BY pin remains a "0" (b usy) until the
internal reset operation is complete, which requires a
time of tREADY (during Embedded Algorithms). The
sysytem can thus monitor RY/BY to determine whether
the reset operation is complete. If RESET is asserted
when a program or erase operation is commpleted within
a time of tREADY (not during Embedded Algorithms).
The system can read data tRH after the RESET pin
returns to VIH.
Refer to the AC Characteristics tables for RESET
parameters and to Figure 24 for the timing diagram.
READ/RESET COMMAND
The read or reset operation is initiated by writing the
read/reset command sequence into the command register. Microprocessor read cycles retrieve array data.
The device remains enabled for reads until the command
register contents are altered.
If program-fail or erase-fail happen, the write of F0H will
reset the device to abort the operation. A valid command must then be written to place the device in the
desired state.
SET-UP AUTOMATIC CHIP/SECTOR ERASE
COMMANDS
Chip erase is a six-bus cycle operation. There are two
"unlock" write cycles. These are followed b y writing the
"set-up" command 80H. Two more "unlock" write cycles are then followed by the chip erase command 10H
or sector erase command 30H.
The Automatic Chip Erase does not require the device
to be entirely pre-programmed prior to executing the Automatic Chip Erase. Upon executing the Automatic Chip
Erase, the device will automatically program and verify
the entire memory for an all-zero data pattern. When the
device is automatically verified to contain an all-zero
pattern, a self-timed chip erase and verify begin. The
erase and verify operations are completed when the data
on Q7 is "1" at which time the device returns to the
Read mode. The system is not required to pro vide any
control or timing during these operations.
When using the Automatic Chip Erase algorithm, note
that the erase automatically terminates when adequate
erase margin has been achieved for the memory array(no
erase verification command is required).
If the Erase operation was unsuccessful, the data on
Q5 is "1"(see Table 7), indicating the erase operation
exceed internal timing limit.
SILICON-ID READ COMMAND
Flash memories are intended for use in applications where
the local CPU alters memory contents. As such, manufacturer and device codes must be accessible while the
device resides in the target system. PROM programmers typically access signature codes by raising A9 to
a high voltage(VID). Howev er, m ultiplexing high voltage
onto address lines is not generally desired system design practice.
The MX29L V004T/B contains a Silicon-ID-Read operation to supple traditional PROM programming methodology . The oper ation is initiated by writing the read silicon
ID command sequence into the command register. F ollowing the command write, a read cycle with A1=VIL,
A0=VIL retrieves the manufacturer code of C2H. A read
cycle with A1=VIL, A0=VIH returns the device code of
B5H for MX29LV004T , B6H for MX29LV004B.
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The automatic erase begins on the rising edge of the
last WE or CE pulse, whichever happens first in the
command sequence and terminates when the data on
Q7 is "1" and the data on Q6 stops toggling for two consecutive read cycles, at which time the device returns
to the Read mode.
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 arra y data
after completing an Automatic Program or Automatic
Erase algorithm.
After the device accepts an Erase 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 erasesuspended 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 rase Suspend/Erase
Resume Commands” for more infor-mation on this mode.
The system
able the device for reading array data if Q5 goes high, or
while in the autoselect mode. See the "Reset Command"
section, next.
must issue the reset command to re-en-
RESET COMMAND
Writing the reset command to the device 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 be-fore
programming begins. This resets the device to reading
array data (also applies to programming in Erase
Suspend mode). Once prog ramming begins ,how ever, the
device ignores reset commands until the operation is
complete.
The reset command may be written between the sequence cycles in an SILICON ID READ command
sequence. Once in the SILICON ID READ mode, the
reset command
data (also applies to SILICON ID READ during Erase
Suspend).
must be written to return to reading array
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If Q5 goes high during a program or erase operation,
writing the reset command returns the device to reading
array data (also applies during Erase Suspend).
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11
SECTOR ERASE COMMANDS
MX29LV004T/B
The Automatic Sector Erase does not require the device to be entirely pre-programmed prior to executing
the Automatic Sector Erase Set-up command and Automatic Sector Erase command. Upon executing the
Automatic Sector Erase command, the device will automatically program and verify the sector(s) memory for
an all-zero data pattern. The system is not required to
provide any control or timing during these operations.
When the sector(s) is automatically verified to contain
an all-zero pattern, a self-timed sector erase and verify
begin. The erase and verify operations are complete
when the data on Q7 is "1" and the data on Q6 stops
toggling for two consecutive read cycles, at which time
the device returns to the Read mode. The system is not
required to provide any control or timing during these
operations.
When using the Automatic sector Erase algorithm, note
that the erase automatically terminates when adequate
erase margin has been achieved for the memory array
T able 7. Write Operation Status
(no erase verification command is required). Sector
erase is a six-bus cycle operation. There are two "unlock" write cycles. These are f ollowed by writing the setup command 80H. Two more "unlock" write cycles are
then followed by the sector erase command 30H. The
sector address is latched on the falling edge of WE or
CE, whichever happens later , while the command(data)
is latched on the rising edge of WE or CE, whichever
happens first. Sector addresses selected are loaded
into internal register on the sixth falling edge of WE or
CE, whichever happens later. Each successive sector
load cycle started by the falling edge of WE or CE,
whichever happens later must begin within 50us from
the rising edge of the preceding WE or CE, whichever
happens first. Otherwise, the loading period ends and
internal auto sector erase cycle starts. (Monitor Q3 to
determine if the sector erase timer window is still open,
see section Q3, Sector Erase Timer .) Any command other
than Sector Erase(30H) or Erase Suspend(B0H) during
the time-out period resets the device to read mode.
StatusQ7Q6Q5Q3Q2RY/BY
(Note1)(Note2)
Byte Program in Auto Program AlgorithmQ7Toggle0N/AN o0
Byte Program in Auto Program AlgorithmQ7Toggle1N/AN o0
Exceeded
Time Limits Auto Erase Algorithm0Toggle11Toggle0
Erase Suspend ProgramQ7Toggle1N/AN/A0
Toggle
Toggle
Note:
1. Q7 and Q2 require a valid address when reading status information. Refer to the appropriate subsection for further
details.
2. Q5 switches to '1' when an Auto Program or Auto Erase operation has exceeded the maximum timing limits.
See "Q5:Exceeded Timing Limits " for more information.
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MX29LV004T/B
ERASE SUSPEND
This command only has meaning while the state machine is executing Automatic Sector Erase operation,
and therefore will only be responded during Automatic
Sector Erase operation. When the Erase Suspend command is written during a sector erase operation, the device requires a maximum of 20us to suspend the erase
operations. However , When the Erase Suspend command
is written during the sector erase time-out, the device
immediately terminates the time-out period and suspends
the erase operation. After this command has been executed, the command register will initiate erase suspend
mode. The state machine will return to read mode automatically after suspend is ready . At this time, state machine only allows the command register to respond to
the Read Memory Array, Erase Resume and program
commands.
The system can determine the status of the program
operation using the Q7 or Q6 status bits, just as in the
standard program operation. After an erase-suspend program operation is complete, the system can once again
read array data within non-suspended sectors.
The device provides Q2, Q3, Q5, Q6, Q7, and R Y/BY to
determine the status of a write operation. If the program
operation was unsuccessful, the data on Q5 is "1"(see
T ab le 7), indicating the program operation exceed internal timing limit. The automatic programming operation is
completed when the data read on Q6 stops toggling for
two consecutive read cycles and the data on Q7 and Q6
are equivalent to data written to these two bits, at which
time the device returns to the Read mode(no program
verify command is required).
BYTE PROGRAM COMMAND SEQUENCE
The device programs one byte of data for each program
operation. The command sequence requires four bus
cycles, and 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 algorithm. The system is
required to provide further controls or timings. The device
automatically generates the program pulses and verifies
the programmed cell margin. Table 1 shows the address
and data requirements for the byte program command
sequence.
not
ERASE RESUME
This command will cause the command register to clear
the suspend state and return back to Sector Erase mode
but only if an Erase Suspend command was previously
issued. Erase Resume will not have any effect in all
other conditions. Another Erase Suspend command can
be written after the chip has resumed erasing.
AUTOMATIC PROGRAM COMMANDS
T o initiate Automatic Progr am mode, A three-cycle command sequence is required. There are two "unlock" write
cycles. These are f ollowed by writing the Automatic Program command A0H.
Once the Automatic Program command is initiated, the
next WE pulse causes a tr ansition to an active programming operation. Addresses are latched on the falling
edge, and data are internally latched on the rising edge
of the WE or CE, whichever happens first. The rising
edge of WE or CE, whiche ver happens first, also begins
the programming operation. The system is not required
to provide further controls or timings. The device will
automatically provide an adequate internally generated
program pulse and verify margin.
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
Q7, Q6, or RY/BY. See "Write Operation Status" for
information on these status bits.
Any commands written to the device during the Embedded Program Algorithm are ignored. Note that a
hardware reset immediately terminates the programming
operat ion. The Byte Prog ram command sequence should
be reinitiated once the device has reset to reading array
data, to ensure data integrity.
Programming is allowed in any sequence and across
sector boundaries. A bit cannot be programmed from a
"0" back to a "1". Attempting to do so may halt the
operation and set Q5 to "1" ,” or cause the Data Polling
algorithm to indicate the operation was successful.
However, a succeeding read will show that the data is
still "0". Only erase operations can convert a "0" to a
"1".
WRITE OPERSTION STATUS
The device provides several bits to determine the status of a write operation: Q2, Q3, Q5, Q6, Q7, and RY/
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MX29LV004T/B
BY. Table 10 and the following subsections describe the
functions of these bits. Q7, R Y/BY, and DQ6 each offer
a method for determining whether a program or erase
operation is complete or in progress. These three bits
are discussed first. Please note that RY/BY pin is provided for 40-pin TSOP pac kage type only.
Q7: Data Polling
The Data Polling bit, Q7, indicates to the host sys-tem
whether an Automatic Algorithm is in progress or completed, or whether the device is in Erase Suspend. Data
Polling is v alid after the rising edge of the final WE pulse
in the program or erase command sequence.
During the Automatic Program algorithm, the device outputs on Q7 the complement of the datum programmed
to Q7. This Q7 status also applies to progr amming during Er ase Suspend. When the Automatic Program algorithm is complete, the device outputs the datum programmed to Q7. The system must provide the progr am
address to read valid status information on Q7. If a program address falls within a protected sector, Data Polling on Q7 is active for approximately 1 us, then the device returns to reading array data.
During the Automatic Erase algorithm, Data Polling produces a "0" on Q7. When the Automatic Erase algorithm is complete, or if the device enters the Erase Suspend mode, Data P olling produces a "1" on Q7. This is
analogous to the complement/true datum out-put described for the Automatic Program algorithm: the erase
function changes all the bits in a sector to "1" prior to
this, the device outputs the "complement,” or "0".” The
system must provide an address within any of the sectors selected for erasure to read valid status information
on Q7.
After an erase command sequence is written, if all sectors selected for erasing are protected, Data P olling on
Q7 is active for approximately 100 us, then the device
returns to reading array data. If not all selected sectors
are protected, the Automatic Erase algorithm erases the
unprotected sectors, and ignores the selected sectors
that are protected.
When the system detects Q7 has changed from the
complement to true data, it can read valid data at Q7-Q0
on the following read cycles. This is because Q7 may
change asynchr onously with Q0-Q6 while Output Enable (OE) is asserted low.
RY/BY:Ready/Busy (for 40-pin TSOP package only)
The RY/BY is a dedicated, open-drain output pin that
indicates whether an Automatic Erase/Program algorithm
is in progress or complete. The RY/BY status is valid
after the rising edge of the final WE or CE, whichever
happens first, in the command sequence. Since R Y/BY
is an open-drain output, sever al RY/BY pins can be tied
together in parallel with a pull-up resistor to Vcc.
If the output is low (Busy), the device is actively erasing
or programming. (This includes programming in the Erase
Suspend mode.)If the output is high (Ready), the device
is ready to read array data (including during the Erase
Suspend mode), or is in the standby mode.
T able 7 sho ws the outputs for R Y/BY during write operation.
Q6:Toggle BIT I
Toggle Bit I on Q6 indicates whether an Automatic Program or Erase algorithm is in progress or complete, or
whether the device has entered the Erase Suspend mode.
Toggle Bit I may be read at any address, and is valid
after the rising edge of the final WE or CE, whichever
happens first, in the command sequence(prior to the program or erase operation), and during the sector timeout.
During an Automatic Program or Erase algorithm operation, successive read cycles to any address cause Q6
to toggle. The system may use either OE or CE to control the read cycles. When the operation is complete , Q6
stops toggling.
After an erase command sequence is written, if all sectors selected for erasing are protected, Q6 toggles and
returns to reading array data. If not all selected sectors
are protected, the Automatic Erase algorithm erases the
unprotected sectors, and ignores the selected sectors
that are protected.
The system can use Q6 and Q2 together to determine
whether a sector is actively erasing or is erase suspended. When the de vice is actively erasing (that is, the
Automatic Erase algorithm is in progress), Q6 toggling.
When the device enters the Erase Suspend mode, Q6
stops toggling. Ho wever, the system m ust also use Q2
to determine which sectors are erasing or erase-suspended. Alternatively, the system can use Q7.
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MX29LV004T/B
If a program address falls within a protected sector, Q6
toggles for approximately 2 us after the program command sequence is written, then returns to reading array
data.
Q6 also toggles during the erase-suspend-program mode,
and stops toggling once the Automatic Program algorithm is complete.
Table 7 shows the outputs for Toggle Bit I on Q6.
Q2:Toggle Bit II
The "T oggle Bit II" on Q2, when used with Q6, indicates
whether a particular sector is actively eraseing (that is,
the Automatic Erase alorithm is in process), or whether
that sector is erase-suspended. Toggle Bit II is valid
after the rising edge of the final WE or CE, whichever
happens first, in the command sequence.
Q2 toggles when the system reads at addresses within
those sectors that have been selected for erasure. (The
system may use either OE or CE to control the read
cycles.) But Q2 cannot distinguish whether the sector
is actively erasing or is erase-suspended. Q6, by comparison, indicates whether the device is actively erasing, or is in Erase Suspend, but cannot distinguish which
sectors are selected for erasure. Thus , both status bits
are required for sectors and mode information. Refer to
Table 7 to compare outputs for Q2 and Q6.
Reading Toggle Bits Q6/ Q2
Whenever the system initially begins reading toggle bit
status, it must read Q7-Q0 at least twice in a row to
determine whether a toggle bit is toggling. T ypically, the
system would note and store the value of the toggle bit
after the first read. After the second read, the system
would compare the new value of the toggle bit with the
first. If the toggle bit is not toggling, the device has
completed the program or erase operation. The system
can read array data on Q7-Q0 on the following read cycle.
Howe v e r, if after the initial two read cycles, the system
determines that the toggle bit is still toggling, the system also should note whether the value of Q5 is high
(see the section on Q5). If it is, the system should then
determine again whether the toggle bit is toggling, since
the toggle bit may have stopped toggling just as Q5 went
high. If the toggle bit is no longer toggling, the device
has successfuly completed the program or erase operation. If it is still toggling, the device did not complete the
operation successfully, and the system must write the
reset command to return to reading array data.
The remaining scenario is that system initially determines
that the toggle bit is toggling and Q5 has not gone high.
The system may continue to monitor the toggle bit and
Q5 through successive read cycles, determining the status as described in the previous paragraph. Alternatively, it may choose to perform other system tasks. In
this case, the system must start at the beginning of the
algorithm when it returns to determine the status of the
operation.
Q5
Exceeded Timing Limits
Q5 will indicate if the program or erase time has exceeded the specified limits(internal pulse count). Under
these conditions Q5 will produce a "1". This time-out
condition indicates that the program or erase cycle was
not successfully completed. Data Polling and Toggle Bit
are the only operating functions of the device under this
condition.
If this time-out condition occurs during sector erase operation, it specifies that a particular sector is bad and it
may not be reused. Howe ver , other sectors are still functional and may be used for the program or erase operation. The device must be reset to use other sectors.
Write the Reset command sequence to the device, and
then execute prog ram or erase command sequence. This
allows the system to continue to use the other active
sectors in the device.
If this time-out condition occurs during the chip erase
operation, it specifies that the entire chip is bad or combination of sectors are bad.
If this time-out condition occurs during the byte programming operation, it specifies that the entire sector containing that byte is bad and this sector maynot be reused, (other sectors are still functional and can be reused).
The time-out condition will not appear if a user tries to
program a non blank location without erasing. Please
note that this is not a device failure condition since the
device was incorrectly used.
P/N:PM0732
REV. 1.1, SEP. 19, 2001
15
MX29LV004T/B
Q3
Sector Erase Timer
After the completion of the initial sector erase command
sequence, the sector erase time-out will begin. Q3 will
remain low until the time-out is complete. Data Polling
and Toggle Bit are valid after the initial sector erase command sequence.
If Data Polling or the Toggle Bit indicates the device has
been written with a valid erase command, Q3 may be
used to determine if the sector erase timer window is
still open. If Q3 is high ("1") the internally controlled
erase cycle has begun; attempts to write subsequent
commands to the device will be ignored until the erase
operation is completed as indicated by Data Polling or
Toggle Bit. If Q3 is low ("0"), the device will accept
additional sector erase commands. To insure the command has been accepted, the system software should
check the status of Q3 prior to and following each subsequent sector erase command. If Q3 were high on the
second status check, the command may not have been
accepted.
POWER SUPPLY DECOUPLING
In order to reduce power switching effect, each device
should have a 0.1uF ceramic capacitor connected between its VCC and GND .
POWER-UP SEQUENCE
The MX29L V004T/B po wers up in the Read only mode.
In addition, the memory contents may only be altered
after successful completion of the predefined command
sequences.
TEMPORARY SECTOR UNPROTECT
This feature allows temporary unprotection of previously
protected sector to change data in-system. The T emporary Sector Unprotect mode is activated by setting the
RESET pin to VID(11.5V-12.5V). During this mode, formerly protected sectors can be programmed or erased
as un-protected sector. Once VID is remove from the
RESET pin,all the previously protected sectors are protected again.
DATA PROTECTION
The MX29LV004T/B is designed to offer protection
against accidental erasure or programming caused by
spurious system level signals that may exist during power
transition. During power up the device automatically resets the state machine in the Read mode. In addition,
with its control register architecture, alteration of the
memory contents only occurs after successful completion of specific command sequences. The device also
incorporates several features to pre vent inadve rtent write
cycles resulting from VCC po wer-up and power-down transition or system noise.
WRITE PULSE "GLITCH" PROTECTION
Noise pulses of less than 5ns(typical) on CE or WE will
not initiate a write cycle.
LOGICAL INHIBIT
Writing is inhibited by holding any one of OE = VIL, CE
= VIH or WE = VIH. T o initiate a write cycle CE and WE
must be a logical zero while OE is a logical one.
SECTOR PROTECTION
The MX29LV004T/B features hardware sector protection. This feature will disable both program and erase
operations for these sectors protected. To activate this
mode, the programming equipment must force VID on
address pin A9 and OE (suggest VID = 12V). Progr amming of the protection circuitry begins on the falling edge
of the WE pulse and is terminated on the rising edge.
Please refer to sector protect algorithm and waveform.
T o v erify programming of the protection circuitry , the programming equipment must force VID on address pin A9
( with CE and OE at VIL and WE at VIH). When A1=VIH,
A0=VIL, A6=VIL, it will produce a logical "1" code at
device output Q0 f or a protected sector . Otherwise the
device will produce 00H for the unprotected sector. In
this mode, the addresses,except for A1, are don't care.
Address locations with A1 = VIL are reserved to read
manufacturer and device codes.(Read Silicon ID)
It is also possible to determine if the sector is protected
in the system by writing a Read Silicon ID command.
Perf orming a read operation with A1=VIH, it will produce
a logical "1" at Q0 for the protected sector .
P/N:PM0732
REV. 1.1, SEP. 19, 2001
16
CHIP UNPROTECT
The MX29LV004T/B also features the chip unprotect
mode, so that all sectors are unprotected after chip
unprotect is completed to incorporate any changes in the
code. It is recommended to protect all sectors before
activating chip unprotect mode.
To activate this mode, the programming equipment must
force VID on control pin OE and address pin A9. The CE
pins must be set at VIL. Pins A6 must be set to VIH.(see
Table 2) Refer to chip unprotect algorithm and waveform
for the chip unprotect algorithm. The unprotection
mechanism begins on the falling edge of the WE pulse
and is terminated on the rising edge.
It is also possible to determine if the chip is unprotected
in the system by writing the Read Silicon ID command.
Performing a read operation with A1=VIH, it will produce
00H at data outputs(Q0-Q7) for an unprotected sector.
MX29LV004T/B
It is noted that all sectors are unprotected after the chip
unprotect algorithm is completed.
P/N:PM0732
REV. 1.1, SEP. 19, 2001
17
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