FLASH
Austin Semiconductor, Inc.
After an erase-suspended program operation is complete,
the system can once again read array data within
non-suspended sectors. The system can determine the status
of the program operation using the DQ7 or DQ6 status bits, just
as in the standard program operation. See “Write Operation
Status” for more information.
The system may also write the autoselect command
sequence when the device is in the Erase Suspend mode. The
device allows reading autoselect codes even at addresses within
erasing sectors, since the codes are not stored in the memory
AS29F040
array. When the device exits the autoselect mode, the device
reverts to the Erase Suspend mode, and is ready for another
valid operation. See “Autoselect Command Sequence” for more
information.
The system must write the Erase Resume command
(address bits are “don’t care”) to exit the erase suspend mode
and continue the sector erase operation. Further writes of the
Resume command are ignored. Another Erase Suspend
command can be written after the device has resumed erasing.
TABLE 4: Command Definitions
Command Sequence
Read
5
6
1
Bus Cycles
First
Second
Third
Fourth
Fifth
Sixth
Addr Data Addr Data Addr Data Addr Data Addr Data Addr Data
RA
XXX
555
555
555
555
555
555
XXX
XXX
RD
F0
AA
AA
AA
AA
AA
AA
B0
30
2AA
2AA
2AA
2AA
2AA
2AA
55
55
55
55
55
55
555
555
555
555
555
555
90
90
90
A0
80
80
X00
X01
SA
X02
PA
555
555
01
A4
00
01
PD
AA
AA
Reset
Autoselect
7
Manufacturer ID
Device ID
Sector Protect Verify
8
Program
Chip Erase
Sector Erase
Erase Suspend
Erase Resume
9
10
Cycles
2,3,4
1
1
4
4
4
4
6
6
1
1
2AA
2AA
55
55
555
SA
10
30
LEGEND:
X = Don’t Care.
RA = Address of the memory location to be read.
RD = Data read from location RA during read operation.
PA = Address of the memory location to be programmed. Addresses latch on the falling edge of the WE\ or CE\ pulse, whichever happens later.
PD = Data to be programmed at location PA. Data latches on the rising edge of WE\ or CE\ pulse, whichever happens first.
SA = Address of the sector to be verified (in autoselect mode) or erased. Address bits A18-A16 uniquely select any sector.
NOTES:
1. See Table 1 for description of bus operations.
2. All values are in hexadecimal.
3. Except when reading array or autoselect data, all command bus cycles are write operations.
4. Address bits A18 - A11 are don’t care for unlock and command cycles, unless SA or PA required.
5. No unlock or command cycles required when reading array data.
6. The Reset command is required to return to reading array data when device is in the autoselect mode, or if DQ5 goes high (while the device is
providing status data).
7. The fourth cycle of the autoselect command sequence is a read cycle.
8. The data is 00h for an unprotected sector and 01h for a protected sector. See “Autoselect Command Sequence” for more information.
9. The system may read and program in non-erasing sectors, or enter the autoselect mode, when in the Erase Suspend mode. The Erase Suspend
command is valid only during a sector erase operation.
10. The Erase Resume command is valid only during the Erase Suspend mode.
AS29F040
Rev. 2.2 09/07
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
9
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