W28V400B/T
Table 4. Command Definitions
(10)
COMMAND
Read Array/Reset
Read Identifier Codes
Read Status Register
Clear Status Register
Block Erase
Word/Byte Write
Block Erase and Word/Byte
Write Suspend
Block Erase and Word/Byte
Write Resume
Notes:
1. BUS operations are defined in Table 3.1 and Table 3.2.
2. X = Any valid address within the device.
IA = Identifier Code Address: see Figure 4. A-1 set to V
IL
or V
IH
in Byte Mode (#BYTE = V
IL
).
BA = Address within the block being erased. The each block can select by the address pin A17 through A12 combination.
WA = Address of memory location to be written.
3. SRD = Data read from status register. See Table 7 for a description of the status register bits.
WD = Data to be written at location WA. Data is latched on the rising edge of #WE or #CE (whichever goes high first).
ID = Data read from identifier codes.
4. Following the Read Identifier Codes command, read operations access manufacturer and device codes. See Read Identifier
Codes Command section for details.
5. If the block is boot block, #WP must be at V
IH
or #RESET must be at V
HH
to enable block erase or word/byte write operations.
Attempts to issue a block erase or word/byte write to a boot block while #WP is V
IH
or #RESET is V
IH
.
6. Either 40H or 10H are recognized by the WSM as the word/byte write setup.
7. Commands other than those shown above are reserved by Winbond for future device implementations and should not be
used.
BUS CYCLES
REQ’D.
1
≥2
(Note 4)
2
1
2 (Note 5)
2 (Note 5, 6)
1 (Note 5)
1 (Note 5)
FIRST BUS CYCLE
Oper(1)
Write
Write
Write
Write
Write
Write
Write
Write
Addr(2)
X
X
X
X
BA
WA
X
X
Data(3)
FFH
90H
70H
50H
20H
40H or
10H
B0H
D0H
SECOND BUS CYCLE
Oper(1)
Read
Read
Write
Write
Addr(2)
IA
X
BA
WA
Data(3)
ID
SRD
D0H
WD
Read Array Command
Upon initial device power-up and after exit from deep power-down mode, the device defaults to read
array mode. This operation is also initiated by writing the Read Array command. The device remains
enabled for reads until another command is written. Once the internal WSM has started a block erase
or word/byte write, the device will not recognize the Read Array command until the WSM completes its
operation unless the WSM is suspended via an Erase Suspend or Word/Byte Write Suspend
command.
The Read Array command functions independently of the V
PP
voltage and #RESET can be V
IH
or V
HH
.
Read Identifier Codes Command
The identifier code operation is initiated by writing the Read Identifier Codes command. Following the
command write, read cycles from addresses shown in Figure 4 retrieve the manufacturer and device
codes (see Table 5 for identifier code values). To terminate the operation, write another valid
command. Like the Read Array command, the Read Identifier Codes command functions
independently of the V
PP
voltage and #RESET can be V
IH
or V
HH
. Following the Read Identifier Codes
command, the following information can be read:
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Publication Release Date: April 11, 2003
Revision A4
WINBOND [ WINBOND ]
