AM29LV008B datasheet(15/39 Pages) AMD

15 / 39 page

Am29LV008T/Am29LV008B

PRELIMINARY

read or programs in a sector not being erased. This

command is applicable only during the Sector Erase

operation, which includes the time-out period for Sector

Erase. The Erase Suspend command will be ignored if

written during the execution of the Chip Erase opera-

tion or Embedded Program Algorithm (but will reset the

chip if written improperly during the command se-

quences.) Writing the Erase Suspend command during

the Sector Erase time-out results in immediate termina-

tion of the time-out period and suspension of the erase

operation. Once in Erase Suspend, the device is avail-

able for read (note that in the Erase Suspend mode, the

Reset/Read command is not required for read opera-

tions and is ignored) or program operations in sectors

not being erased. Any other command written during

the Erase Suspend mode will be ignored, except for the

Erase Resume command. Writing the Erase Resume

command resumes the sector erase operation. The ad-

dresses are “don’t cares” when writing the Erase Sus-

pend or Erase Resume command.

When the Erase Suspend command is written during a

Sector Erase operation, the chip will take between 0.1

µs and 20 µs to actually suspend the operation and go

into erase suspended read mode (pseudo-read mode),

at which time the user can read or program from a sec-

tor that is not erase suspended. Reading data in this

mode is the same as reading from the standard read

mode, except that the data must be read from sectors

that have not been erase suspended.

Successively reading from the erase-suspended sector

while the device is in the erase-suspend-read mode will

cause DQ2 to toggle. Polling DQ2 on successive reads

from a given sector provides the system the ability to

determine if a sector is in Erase Suspend.

After entering the erase-suspend-read mode, the user

can program the device by writing the appropriate com-

mand sequence for Byte Program. This program mode

is known as the erase suspend-program mode. Again,

programming in this mode is the same as programming

in the regular Byte Program mode, except that the data

must be programmed to sectors that are not erase sus-

pended. Successively reading from the erase sus-

pended sector while the device is in the erase

suspend-program mode will cause DQ2 to toggle.

Completion of the erase suspend operation can be de-

termined two ways:

s Checking the status of the toggle bit DQ2

s Checking the status of the RY/BY pin

To resume the operation of Sector Erase, the Resume

command (30H) should be written. Any further writes of

the Resume command at this point will be ignored.

However, another Erase Suspend command can be

written after the device has resumed sector erase op-

erations.

When the erase operation has been suspended, the

device defaults to the erase-suspend-read mode.

Reading data in this mode is the same as reading from

the standard read mode except that the data must be

read

from

sectors

that

hav e

not

been

erase-suspended.

To resume the operation of Sector Erase, the Resume

command (30H) should be written. Any further writes of

the Resume command at this point will be ignored. An-

other Erase Suspend command can be written after the

chip has resumed erasing.

Write Operation Status

Address Sensitivity of Write Status Flags

Detailed in Table 6 are all the status ﬂags that can be

used to check the status of the device for current mode

operation. During Sector Erase, the part provides the

status ﬂags automatically to the I/O ports. The informa-

tion on DQ2 is address sensitive. This means that if an

address from an erasing sector is consecutively read,

then the DQ2 bit will toggle. However, DQ2 will not tog-

gle if an address from a non-erasing sector is consec-

utively read. This allows the user to determine which

sectors are erasing and which are not.

Once Erase Suspend is entered, address sensitivity

still applies. If the address of a non-erasing sector (that

is, one available for read) is provided, then stored data

can be read from the device. If the address of an eras-

ing sector (that is, one unavailable for read) is applied,

the device will output its status bits. Conﬁrmation of sta-

tus bits can be done by doing consecutive reads to tog-

gle DQ2, which is active throughout the Embedded

Erase mode, including Erase Suspend.

In order to effectively use DATA Polling to determine if

the device has entered into erase-suspended mode, it

is necessary to apply a sector address from a sector

being erased.

AM29LV008B Datasheet(PDF) 15 Page - Advanced Micro Devices

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