Numonyx® Embedded Flash Memory (J3 65 nm) Single Bit per Cell (SBC)
9.1.1
Clearing the Status Register
The Status Register (SR) contain Status and error bits which are set by the device. SR
status bits are cleared by the device, however SR error bits are cleared by issuing the
Clear SR command (see Table 21). Resetting the device also clears the SR.
Table 21: Clear Status Register Command Bus-Cycles
Setup Write Cycle
Command
Confirm Write Cycle
Address Bus Data Bus
Address Bus
Data Bus
0050h
Clear Status Register
Device Address
—
—
Issuing the Clear SR command places the device in Read SR mode.
Note:
Care should be taken to avoid SR ambiguity. If a command sequence error occurs while
in an Erase Suspend condition, the SR will indicate a Command Sequence error by
setting SR.4 and SR.5. When the erase operation is resumed (and finishes), any errors
that may have occurred during the erase operation will be masked by the Command
Sequence error. To avoid this situation, clear the Status Register prior to resuming a
suspended erase operation. The Clear SR command functions independent of the
voltage level on VPEN.
9.2
Read Operations
Four types of data can be read from the device: array data, device information, CFI
data, and device status. Upon power-up or return from reset, the device defaults to
Read Array mode. To change the device’s read mode, the appropriate command must
be issued to the device. Table 22 shows the command codes used to configure the
device for the desired read mode. The following sections describe each read mode.
Table 22: Read Mode Command Bus-Cycles
Setup Write Cycle
Address Bus Data Bus
Confirm Write Cycle
Address Bus Data Bus
Command
Read Array
Device Address
Device Address
Device Address
Device Address
00FFh
0070h
0090h
0098h
—
—
Read Status Register
Read Device Information
CFI Query
—
—
—
—
—
—
9.2.1
Read Array
Upon power-up or return from reset, the device defaults to Read Array mode. Issuing
the Read Array command places the device in Read Array mode. Subsequent reads
output array data on DQ[15:0]. The device remains in Read Array mode until a
different read command is issued, or a program or erase operation is performed, in
which case, the read mode is automatically changed to Read Status.
To change the device to Read Array mode while it is programming or erasing, first issue
the Suspend command. After the operation has been suspended, issue the Read Array
command. When the program or erase operation is subsequently resumed, the device
will automatically revert back to Read Status mode.
Note:
Issuing the Read Array command to the device while it is actively programming or
erasing causes subsequent reads from the device to output invalid data. Valid array
data is output only after the program or erase operation has finished.
Jan 2011
208032-03
Datasheet
35
MICRON [ MICRON TECHNOLOGY ]
