![](http://datasheet.mmic.net.cn/390000/HY27SS08561M_datasheet_16812295/HY27SS08561M_12.png)
Rev 0.7 / Oct. 2004
12
HY27SS(08/16)561M Series
HY27US(08/16)561M Series
256Mbit (32Mx8bit / 16Mx16bit) NAND Flash
COMMAND SET
All bus write operations to the device are interpreted by the Command Interface. The Commands are input on I/O
0
-I/
O
7
and are latched on the rising edge of Write Enable when the Command Latch Enable signal is high. Device opera-
tions are selected by writing specific commands to the Command Register. The two-step command sequences for pro-
gram and erase operations are imposed to maximize data security.
The Commands are summarized in Table 5, Commands.
Table 5: Command Set
Note: (1). Any undefined command sequence will be ignored by the device.
(2). The 50h command is valid only when GND(Pin#6) is Low.
(3). Bus Write Operation(1
st
, 2
nd
and 3
rd
Cycle) : The bus cycles are only shown for issuing the codes. The cycles required to
input the addresses or input/output data are not shown.
DEVICE OPERATIONS
Pointer Operations
As the NAND Flash memories contain two different areas for x16 devices and three different areas for x8 devices (see
Figure 8) the read command codes (00h, 01h, 50h) are used to act as pointers to the different areas of the memory
array (they select the most significant column address).
The Read A and Read B commands act as pointers to the main memory area. Their use depends on the bus width of
the device.
- In x16 devices the Read A command (00h) sets the pointer to Area A (the whole of the main area) that is Words 0
to 255.
- In x8 devices the Read A command (00h) sets the pointer to Area A (the first half of the main area) that is Bytes 0
to 255, and the Read B command (01h) sets the pointer to Area B (the second half of the main area) that is Bytes 256
to 511.
In both the x8 and x16 devices the Read C command (50h), acts as a pointer to Area C (the spare memory area) that
is Bytes 512 to 527 or Words 256 to 263.
Once the Read A and Read C commands have been issued the pointer remains in the respective areas until another
FUNCTION
1st CYCLE
2nd CYCLE
3rd CYCLE
Command accepted during busy
READ A
00h
01h
(1)
50h
(2)
-
-
READ B
-
-
READ C
-
-
READ ELECTRINIC SIGNATURE
90h
-
-
READ STATUS REGISTER
70h
-
-
Yes
PAGE PROGRAM
80h
10h
-
COPY BACK PROGRAM
00h
8Ah
10h
BLOCK ERASE
60h
D0h
-
RESET
FFh
-
-
Yes