May 9, 2006 Am29F004B_00_E4

Am29F004B

19

D A TA

SH EE T

erase commands is always less than 50

μs. See also the

Sector Erase Command Sequence on page 14 section.

After the sector erase command sequence is written, the

system should read the status on DQ7 (Data# Polling) or DQ6

(Toggle Bit I) to ensure the device accepts the command

sequence, and then read DQ3. If DQ3 is 1, the internally con-

trolled erase cycle started; all further commands (other than

Erase Suspend) are ignored until the erase operation is com-

plete. If DQ3 is 0, the device accepts additional sector erase

commands. To ensure the command was accepted, the

system software should check the status of DQ3 prior to and

following each subsequent sector erase command. If DQ3 is

high on the second status check, the last command might not

have been accepted. Table 6 on page 19 shows the outputs

for DQ3.

Table 6.

Write Operation Status

Notes:

1.

DQ7 and DQ2 require a valid address when reading status information. Refer to the appropriate subsection for further details.

2.

DQ5 switches to 1 when an Embedded Program or Embedded Erase operation has exceeded the maximum timing limits. See DQ5:

Exceeded Timing Limits on page 18 for more information.

START

No

Yes

Yes

DQ5 = 1?

No

Yes

Toggle Bit

= Toggle?

No

Program/Erase

Operation Not

Complete, Write

Reset Command

Program/Erase

Operation Complete

Read DQ7–DQ0

Toggle Bit

= Toggle?

Read DQ7–DQ0

Twice

Read DQ7–DQ0

Notes:

1.

Read toggle bit twice to determine whether or not it is toggling.

See text.

2.

Recheck toggle bit because it may stop toggling as DQ5

changes to

Figure 6.

Toggle Bit Algorithm

(Notes

1, 2)

(Note

1)

Operation

DQ7

(Note 1)

DQ6

DQ5

(Note 2)

DQ3

DQ2

(Note 1)

Standard

Mode

Embedded Program Algorithm

DQ7#

Toggle

0

N/A

No toggle

Embedded Erase Algorithm

0

Toggle

0

1

Toggle

Erase

Suspend

Mode

Reading within Erase

Suspended Sector

1

No toggle

0

N/A

Toggle

Reading within Non-Erase Suspended

Sector

Data

Data

Data

Data

Data

Erase-Suspend-Program

DQ7#

Toggle

0

N/A

N/A