AM29LV640MT110REF datasheet(35/66 Pages) AMD

35 / 66 page

February 1, 2007 26190C8

Am29LV640MT/B

D A TA

SH EET

The system must write the Program Resume com-

mand (address bits are don’t care) to exit the Program

Suspend mode and continue the programming opera-

tion. Further writes of the Resume command are ig-

nored. Another Program Suspend command can be

written after the device has resume programming.

Figure 6.

Program Suspend/Program Resume

Chip Erase Command Sequence

Chip erase is a six bus cycle operation. The chip erase

command sequence is initiated by writing two unlock

cycles, followed by a set-up command. Two additional

unlock write cycles are then followed by the chip erase

command, which in turn invokes the Embedded Erase

algorithm. The device does not require the system to

preprogram prior to erase. The Embedded Erase algo-

rithm automatically preprograms and verifies the entire

memory for an all zero data pattern prior to electrical

erase. The system is not required to provide any con-

trols or timings during these operations. Tables 12 and

13 shows the address and data requirements for the

chip erase command sequence. Note that the autose-

lect and CFI functions are unavailable when an erase

operation is in progress.

When the Embedded Erase algorithm is complete, the

device returns to the read mode and addresses are no

longer latched. The system can determine the status

of the erase operation by using DQ7, DQ6, or DQ2.

See Write Operation Status on page 38 for information

on these status bits.

Any commands written during the chip erase operation

are ignored. However, note that a hardware reset im-

mediately terminates the erase operation. If that oc-

curs, the chip erase command sequence should be

reinitiated once the device has returned to reading

array data, to ensure data integrity.

Figure 7 illustrates the algorithm for the erase opera-

tion. See the table, Erase and Program Operations on

page 48 in AC Characteristics for parameters, and Fig-

ure 19 for timing diagrams.

Sector Erase Command Sequence

Sector erase is a six bus cycle operation. The sector

erase command sequence is initiated by writing two

unlock cycles, followed by a set-up command. Two ad-

ditional unlock cycles are written, and are then fol-

lowed by the address of the sector to be erased, and

the sector erase command. Tables 12 and 13 shows

the address and data requirements for the sector

erase command sequence. Note that the autoselect

and CFI functions are unavailable when an erase op-

eration is in progress.

The device does not require the system to preprogram

prior to erase. The Embedded Erase algorithm auto-

matically programs and verifies the entire memory for

an all zero data pattern prior to electrical erase. The

system is not required to provide any controls or tim-

ings during these operations.

After the command sequence is written, a sector erase

time-out of 50 µs occurs. During the time-out period,

additional sector addresses and sector erase com-

mands can be written. Loading the sector erase buffer

can be done in any sequence, and the number of sec-

tors can be from one sector to all sectors. The time be-

tween these additional cycles must be less than 50 µs,

otherwise erasure can begin. Any sector erase ad-

dress and command following the exceeded time-out

might or might not be accepted. It is recommended

that processor interrupts be disabled during this time

to ensure all commands are accepted. The interrupts

can be re-enabled after the last Sector Erase com-

mand is written. Any command other than Sector

Erase or Erase Suspend during the time-out pe-

riod resets the device to the read mode. The sys-

tem must rewrite the command sequence and any

additional addresses and commands.

Program Operation

or Write-to-Buffer

Sequence in Progress

Write Program Suspend

Command Sequence

Command is also valid for

Erase-suspended-program

operations

Autoselect and SecSi Sector

read operations are also allowed

Data cannot be read from erase- or

program-suspended sectors

Write Program Resume

Command Sequence

Read data as

required

Done

reading?

Yes

Write address/data

XXXh/30h

Device reverts to

operation prior to

Program Suspend

Write address/data

XXXh/B0h

Wait 15

μs

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