General Description
Micron NAND Flash devices include an asynchronous data interface for high-perform-
ance I/O operations. These devices use a highly multiplexed 8-bit bus (I/Ox) to transfer
commands, address, and data. There are five control signals used to implement the
asynchronous data interface: CE#, CLE, ALE, WE#, and RE#. Additional signals control
hardware write protection and monitor device status (R/B#).
This hardware interface creates a low pin-count device with a standard pinout that re-
mains the same from one density to another, enabling future upgrades to higher densi-
ties with no board redesign.
A target is the unit of memory accessed by a chip enable signal. A target contains one or
more NAND Flash die. A NAND Flash die is the minimum unit that can independently
execute commands and report status. A NAND Flash die, in the ONFI specification, is
referred to as a logical unit (LUN). There is at least one NAND Flash die per chip enable
signal. For further details, see Device and Array Organization.
This device has an internal 4-bit ECC that can be enabled using the GET/SET features.
See Internal ECC and Spare Area Mapping for ECC for more information.
Signal Descriptions
Table 1: Signal Definitions
Notes:  1.See Device and Array Organization for detailed signal connections.
2.See Asynchronous Interface Bus Operation for detailed asynchronous interface signal
descriptions.
Column Address Operations
The column address operations affect how data is input to and output from the cache
registers within the selected die (LUNs). These features provide host flexibility for man-
aging data, especially when the host internal buffer is smaller than the number of data
bytes or words in the cache register.
When the asynchronous interface is active, column address operations can address any
byte in the selected cache register.
RANDOM DATA READ (05h-E0h)
The RANDOM DATA READ (05h-E0h) command changes the column address of the se-
lected cache register and enables data output from the last selected die (LUN). This
command is accepted by the selected die (LUN) when it is ready (RDY = 1; ARDY = 1). It
is also accepted by the selected die (LUN) during CACHE READ operations
(RDY = 1; ARDY = 0).
Writing 05h to the command register, followed by two column address cycles containing
the column address, followed by the E0h command, puts the selected die (LUN) into
data output mode. After the E0h command cycle is issued, the host must wait at least
t WHR before requesting data output. The selected die (LUN) stays in data output mode
until another valid command is issued.
In devices with more than one die (LUN) per target, during and following interleaved
die (multi-LUN) operations, the READ STATUS ENHANCED (78h) command must be
issued prior to issuing the RANDOM DATA READ (05h-E0h). In this situation, using the
RANDOM DATA READ (05h-E0h) command without the READ STATUS ENHANCED
(78h) command will result in bus contention because two or more die (LUNs) could
output data.
Figure 32: RANDOM DATA READ (05h-E0h) Operation Array Cycle type
I/O[7:0]
SR[6]
ble for additional PROGRAM PAGE CACHE (80h-15h) or PROGRAM PAGE (80h-10h) commands. The PROGRAM PAGE CACHE (80h-15h) command is accepted by the die (LUN) when it is ready (RDY =1, ARDY = 1). It is also accepted by the die (LUN) when busy with a PROGRAM PAGE CACHE (80h-15h) operation (RDY = 1, ARDY = 0).
To input a page to the cache register to move it to the NAND array at the block and page address specified, write 80h to the command register. Unless this command has been preceded by a PROGRAM PAGE TWO-PLANE (80h-11h) command, issuing the 80h to the command register clears all of the cache registers' contents on the selected target. Then write n address cycles containing the column address and row address. Data input cycles follow. Serial data is input beginni
ng at the column address specified. At any time during the data input cycle the RANDOM DATA INPUT (85h) and PROGRAM FOR IN-TERNAL DATA INPUT (85h) commands may be issued. When data input is complete, write 15h to the command register. The selected LUN will go busy
(RDY = 0, ARDY = 0) for t CBSY to allow the data register to become available from a pre-vious program cache operation, to copy data from the cache register to the data register, and then to begin moving the data register contents to the specified page and block ad-dress.
To determine the progress of t CBSY, the host can monitor the target's R/B# signal or, al-ternatively, the status operations (70h, 78h) can be used. When the LUN’s status shows that it is busy with a PROGRAM CACHE operation (RDY = 1, ARDY = 0), the host should check the status of the FAILC bit to see if a previous cache operation was successful.accepted什么意思中文
If, after t CBSY, the host wants to wait for the program cache operation to complete, without issuing the PROGRAM PAGE (80h-10h) command, the host should monitor AR-DY until it is 1. The host should then check the status of the FAIL and FAILC bits.
In devices with more than one die (LUN) per target, during and following interleaved die (multi-LUN) operations, the READ STATUS ENHANCED (78h) command must be used to select only one die (L
UN) for status output. Use of the READ STATUS (70h) com-mand could cause more than one die (LUN) to respond, resulting in bus contention. The PROGRAM PAGE CACHE (80h-15h) command is used as the final command of a two-plane program cache operation. It is preceded by one or more PROGRAM PAGE TWO-PLANE (80h-11h) commands. Data for all of the addressed planes is transferred from the cache registers to the corresponding data registers, then moved to the NAND Flash array. The host should check the status of the operation by using the status opera-tions (70h, 78h).
Figure 43: PROGRAM PAGE CACHE (80h–15h) Operation (Start)Cycle type I/O[7:0]RDY
Figure 44: PROGRAM PAGE CACHE (80h–15h) Operation (End)
As defined for
PAGE CACHE PROGRAM
PROGRAM PAGE TWO-PLANE (80h-11h)

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