AM29LV320DB90WMF datasheet(28/55 Pages) SPANSION

28 / 55 page

Am29LV320D

November 15, 2004

time-out period resets the device to the

read mode. The system must rewrite the com-

mand sequence and any additional addresses

and commands.

The system can monitor DQ3 to determine if

the sector erase timer timed out (See the sec-

tion “DQ3: Sector Erase Timer” on page 32.).

The time-out begins from the rising edge of the

final WE# pulse in the command sequence.

When the Embedded Erase algorithm is com-

plete, the device returns to reading array data

and addresses are no longer latched. The sys-

tem can determine the status of the erase op-

eration by reading DQ7, DQ6, DQ2, or RY/BY#

in the erasing sector. Refer to “Write Operation

Status” on page 30 for information on these

status bits.

Once the sector erase operation begins, only

the Erase Suspend command is valid. All other

commands are ignored. However, note that a

hardware reset immediately terminates the

erase operation. If that occurs, the sector erase

command sequence should be reinitiated once

the device returns to reading array data, to en-

sure data integrity.

Figure 5, on page 28 illustrates the algorithm

for the erase operation. Refer to table “Erase

and Program Operations” on page 41 for pa-

rameters, and Figure 19, on page 43 for timing

diagrams.

Erase Suspend/Erase Resume Commands

The Erase Suspend command, B0h, allows the

system to interrupt a sector erase operation

and then read data from, or program data to,

any sector not selected for erasure. This com-

mand is valid only during the sector erase oper-

ation, including the 50 µs time-out period

during the sector erase command sequence.

The Erase Suspend command is ignored if writ-

ten during the chip erase operation or Embed-

ded Program algorithm.

When the Erase Suspend command is written

during the sector erase operation, the device

requires a maximum of 20 µs to suspend the

erase operation. However, when the Erase Sus-

pend command is written during the sector

erase time-out, the device immediately termi-

nates the time-out period and suspends the

erase operation.

After the erase operation is suspended, the de-

vice enters the erase-suspend-read mode. The

system can read data from or program data to

any sector not selected for erasure. (The device

“erase suspends” all sectors selected for era-

sure.) Reading at any address within erase-sus-

pended sectors produces status information on

DQ7–DQ0. The system can use DQ7, or DQ6

and DQ2 together, to determine if a sector is

actively erasing or is erase-suspended. Refer to

the “Write Operation Status” on page 30 sec-

tion for information on these status bits.

After an erase-suspended program operation is

complete, the device returns to the erase-sus-

pend-read mode. The system can determine

the status of the program operation using the

DQ7 or DQ6 status bits, just as in the standard

Byte Program operation. Refer to “Write Opera-

tion Status” on page 30 for more information.

In the erase-suspend-read mode, the system

can also issue the autoselect command se-

quence. Refer to “Autoselect Mode” on page 16

and “Autoselect Command Sequence” on

page 25 for details.

To resume the sector erase operation, the sys-

tem must write the Erase Resume command.

Further writes of the Resume command are ig-

nored. Another Erase Suspend command can

be written after the chip resumes erasing.

Figure 5. Erase Operation

START

Write Erase

Command Sequence

(Notes 1, 2)

Data Poll to Erasing

Bank from System

Data = FFh?

Yes

Erasure Completed

Embedded

Erase

algorithm

in progress

Notes:

1. See Table 14, on page 29 for erase command

sequence.

2. See the section on DQ3 for information on the

sector erase timer.

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