AM29DS323D datasheet(29/56 Pages) AMD

29 / 56 page

October 10, 2006 23480A5

Am29DS323D

D A TA

SH EE T

DQ7, DQ6, DQ2, or RY/BY# in the erasing bank. Refer

to the Write Operation Status section for information

on these status bits.

Once the sector erase operation has begun, only the

Erase Suspend command is valid. All other com-

mands 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 that bank has returned to

reading array data, to ensure data integrity.

Figure 4 illustrates the algorithm for the erase opera-

tion. Refer to the Erase and Program Operations

tables in the AC Characteristics section for parame-

ters, and Figure 19 section for timing diagrams.

Erase Suspend/Erase Resume

Commands

The Erase Suspend command, B0h, allows the sys-

tem to interrupt a sector erase operation and then read

data from, or program data to, any sector not selected

for erasure. The bank address is required when writing

this command. This command is valid only during the

sector erase operation, including the 50 µs time-out

period during the sector erase command sequence.

The Erase Suspend command is ignored if written dur-

ing the chip erase operation or Embedded Program

algorithm.

When the Erase Suspend command is written during

the sector erase operation, the device requires a max-

imum of 20 µs to suspend the erase operation.

However, when the Erase Suspend command is writ-

ten during the sector erase time-out, the device

immediately terminates the time-out period and sus-

pends the erase operation.

After the erase operation has been suspended, the

bank enters the erase-suspend-read mode. The sys-

tem can read data from or program data to any sector

not selected for erasure. (The device “erase sus-

pends” all sectors selected for erasure.) Reading at

any address within erase-suspended sectors pro-

duces 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 section for infor-

mation on these status bits.

After an erase-suspended program operation is com-

plete, the bank returns to the erase-suspend-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 the Write Operation Status section for more

information.

In the erase-suspend-read mode, the system can also

issue the autoselect command sequence. Refer to the

Autoselect Mode and Autoselect Command Sequence

sections for details.

To resume the sector erase operation, the system

must write the Erase Resume command. The bank

address of the erase-suspended bank is required

when writing this command. Further writes of the Re-

sume command are ignored. Another Erase Suspend

command can be written after the chip has resumed

erasing.

Figure 4.

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 for erase command sequence.

2. See the section on DQ3 for information on the sector

erase timer.

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