AM29F004B AMD [Advanced Micro Devices], AM29F004B Datasheet - Page 21

• Manufacturer Part Number: AM29F004B
• Description: 4 Megabit (512 K x 8-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

erase commands is always less than 50 μs. See also the
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.
for DQ3.
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
8/5/05
Sector Erase Command Sequence on page 14
Standard
Suspend
Exceeded Timing Limits on page 18
Erase
Mode
Mode
Embedded Program Algorithm
Reading within Erase
Suspended Sector
Reading within Non-Erase Suspended
Embedded Erase Algorithm
Operation
Erase-Suspend-Program
Table 6 on page 19
Sector
A D V A N C E
for more information.
shows the outputs
Table 6. Write Operation Status
section.
(Note 1)
DQ7#
DQ7#
DQ7
Data
Am29F004B
0
1
I N F O R M A T I O N
Notes:
1. Read toggle bit twice to determine whether or not it is toggling.
2. Recheck toggle bit because it may stop toggling as DQ5
No toggle
Toggle
Toggle
Toggle
Data
DQ6
See text.
changes to
No
Figure 6. Toggle Bit Algorithm
Complete, Write
Reset Command
Read DQ7–DQ0
Read DQ7–DQ0
Read DQ7–DQ0
1
Program/Erase
Operation Not
. See text.
(Note 2)
Toggle Bit
Toggle Bit
DQ5 = 1?
= Toggle?
= Toggle?
START
DQ5
Data
Twice
0
0
0
0
Yes
Yes
Yes
(Notes
1, 2)
Operation Complete
DQ3
Data
No
No
N/A
N/A
N/A
Program/Erase
1
(Note
1)
No toggle
(Note 1)
Toggle
Toggle
Data
DQ2
N/A
DQ5:
19