2 MEG x 16
ASYNC/PAGE/BURST FLASH MEMORY
Table 6
Bus Operations
MODE
RST#
CE#
ADV#
OE#
WE#
ADDRESS DQ0–DQ15
Read (array, status registers,
device identification register, or
query)
VIH
VIL
VIL
VIL
VIH
X
DOUT
Standby
Output disable
Reset
VIH
VIH
VIL
VIH
VIH
X
X
X
X
X
X
X
X
X
X
X
High-Z
High-Z
High-Z
DIN
X
X
X
Write
VIH
VIL
VIL
VIH
VIL
Table 7
Status Register Bit Definitions
WSMS
ESS
ES
PS
VPPS
PSS
BLS
R
7
6
5
4
3
2
1
0
STATUS
BIT # STATUS REGISTER BIT
DESCRIPTION
WRITE STATE MACHINE STATUS (WSMS) Check write state machine bit first to determine word
SR7
1 = Ready
0 = Busy
program or block erase completion, before checking program
or erase status bits.
SR6
ERASE SUSPEND STATUS (ESS)
1 = BLOCK ERASE Suspended
0 = BLOCK ERASE in
When ERASE SUSPEND is issued, WSM halts execution and
sets both WSMS and ESS bits to “1.” ESS bit remains set to “1”
until an ERASE RESUME command is issued.
Progress/Completed
SR5
SR4
SR3
ERASE STATUS (ES)
1 = Error in Block Erasure
0 = Successful BLOCK ERASE
When this bit is set to “1,” WSM has applied the maximum
number of erase pulses to the block and is still unable to
verify successful block erasure.
PROGRAM STATUS (PS)
1 = Error in PROGRAM
0 = Successful PROGRAM
When this bit is set to “1,” WSM has attempted but failed to
program a word.
VPP STATUS (VPPS)
1 = VPP Low Detect, Operation
Abort
The VPP status bit does not provide continuous indication of
the VPP level. The WSM interrogates the VPP level only after
the program or erase command sequences have been entered
and informs the system if VPP < 0.9V. The VPP level is also
checked before the PROGRAM/ERASE is verified by the WSM.
0 = VPP = OK
SR2
SR1
PROGRAM SUSPEND STATUS (PSS)
1 = PROGRAM Suspended
0 = PROGRAM in Progress/Completed
When PROGRAM SUSPEND is issued, WSM halts execution and
sets both WSMS and PSS bits to “1.” PSS bit remains set to “1”
until a PROGRAM RESUME command is issued.
BLOCK LOCK STATUS (BLS)
If a PROGRAM or ERASE operation is attempted to one of the
locked blocks, this is set by the WSM. The operation specified
is aborted and the device is returned to read status mode.
1 = PROGRAM/ERASE Attempted on a
Locked Block; Operation Aborted
0 = No Operation to Locked Blocks
SR0
RESERVED FOR FUTURE ENHANCEMENT This bit is reserved for future use.
2 Meg x 16 Async/Page/Burst Flash Memory
MT28F322D20FH_4.p65 – Rev. 4, Pub. 7/02
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2002, Micron Technology, Inc.
14
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