©2011 Silicon Storage Technology, Inc. DS25034A 09/11
11
4 Mbit (x16) Multi-Purpose Flash
SST39WF400B
Data Sheet
Microchip Technology Company
Operations
Table 3: Operation Modes Selection
Mode CE# OE# WE# DQ Address
Read V
IL
V
IL
V
IH
D
OUT
A
IN
Program V
IL
V
IH
V
IL
D
IN
A
IN
Erase V
IL
V
IH
V
IL
X
1
1. X can be V
IL
or V
IH
, but no other value.
Sector or Block address,
XXH for Chip-Erase
Standby V
IH
X X High Z X
Write Inhibit X V
IL
X High Z/ D
OUT
X
XXV
IH
High Z/ D
OUT
X
Product Identification
Software Mode V
IL
V
IL
V
IH
See Table 4
T3.0 25034
Table 4: Software Command Sequence
Command
Sequence
1st Bus
Write Cycle
2nd Bus
Write Cycle
3rd Bus
Write Cycle
4th Bus
Write Cycle
5th Bus
Write Cycle
6th Bus
Write Cycle
Addr
1
1. Address format A
14
-A
0
(Hex), Addresses A
MS-
A
15
can be V
IL
or V
IH
, but no other value, for the Command sequence.
A
MS
= Most significant address
A
MS
=A
17
for SST39WF400B
Data
2
2. DQ
15
-DQ
8
can be V
IL
or V
IH
, but no other value, for the Command sequence
Addr
1
Data
2
Addr
1
Data
2
Addr
1
Data
2
Addr
1
Data
2
Addr
1
Data
2
Word-Program 5555H AAH 2AAAH 55H 5555H A0H WA
3
3. WA = Program word address
Data
Sector-Erase 5555H AAH 2AAAH 55H 5555H 80H 5555H AAH 2AAAH 55H SA
X
4
4. SA
X
for Sector-Erase; uses A
MS
-A
11
address lines
BA
X
for Block-Erase; uses A
MS
-A
15
address lines
30H
Block-Erase 5555H AAH 2AAAH 55H 5555H 80H 5555H AAH 2AAAH 55H BA
X
4
50H
Chip-Erase 5555H AAH 2AAAH 55H 5555H 80H 5555H AAH 2AAAH 55H 5555H 10H
Software ID Entry
5,6
5. The device does not remain in Software Product ID mode if powered down.
6. With A
MS
-A
1
= 0; SST Manufacturer’s ID = 00BFH, is read with A
0
=0,
SST39WF400B Device ID = 272EH, is read with A
0
=1.
5555H AAH 2AAAH 55H 5555H 90H
SST CFI Query
Entry
5
5555H AAH 2AAAH 55H 5555H 98H
General CFI Query
Mode
55H 98H
Software ID Exit
7
/
CFI Exit
7. Both Software ID Exit operations are equivalent
XXH F0H
Software ID Exit
7
/
CFI Exit
5555H AAH 2AAAH 55H 5555H F0H
T4.0 25034
