Numonyx® Embedded Flash Memory (J3 65 nm) Single Bit per Cell (SBC)
9.0
Flash Operations
This section describes the operational features of flash memory. Operations are
command-based, wherein command codes are first issued to the device, then the
device performs the desired operation. All command codes are issued to the device
using bus-write cycles (see Chapter 8.0, “Bus Interface”). A complete list of available
command codes can be found in Section 11.0, “Device Command Codes” on page 47.
9.1
Status Register
The Status Register (SR) is an 8-bit, read-only register that indicates device status and
operation errors. To read the Status Register, issue the Read Status Register command.
Subsequent reads output Status Register information on DQ[7:0], and 00h on
DQ[15:8].
SR status bits are set and cleared by the device. SR error bits are set by the device, but
must be cleared using the Clear Status Register command. Upon power-up or exit from
reset, the Status Register defaults to 80h. Page-mode reads are not supported in this
read mode. Status Register contents are latched on the falling edge of OE# or CEX (CEX
low is defined as the combination of pins CE0, CE1, and CE2 that enable the device.
CEX high is defined as the combination of pins CE0, CE1, and CE2 that disable the
device). OE# must toggle to VIH or the device must be disabled before further reads to
update the Status Register latch. The Read Status Register command functions
independently of VPEN voltage.
Table 20 shows Status Register bit definitions.
Table 20: Status Register Bit Definitions
Status Register (SR)
Default Value = 80h
Program/
Erase
Voltage
Error
Erase
Suspend
Status
Program
Suspend
Status
Ready
Status
Erase
Error
Program
Error
Block-Locked
Reserved
0
Error
7
6
5
4
3
2
1
Bit
Name
Ready Status
Description
0 = Device is busy. SR[6:0] are invalid (Not driven);
1 = Device is ready. SR[6:0] are valid.
7
6
5
0 = Erase suspend not in effect.
1 = Erase suspend in effect.
Erase Suspend Status
SR.5 SR.4
Erase Error
0
0
1
1
0
1
0
1
= Program or erase operation successful.
= Program error - operation aborted.
= Erase error - operation aborted.
Command
Sequence
Error
Program
Error
4
= Command sequence error - command aborted.
0 = Within acceptable limits during program or erase operation.
3
2
Program/Erase Voltage Error
Program Suspend Status
1 = Not within acceptable limits during program or erase operation - Operation
aborted.
0 = Program suspend not in effect.
1 = Program suspend in effect.
0 = Block NOT locked during program or erase - operation successful.
1 = Block locked during program or erase - operation aborted.
1
0
Block-Locked Error
Reserved
Reserved
Datasheet
34
Jan 2011
208032-03
MICRON [ MICRON TECHNOLOGY ]
