M28W320FSU STMICROELECTRONICS [STMicroelectronics], M28W320FSU Datasheet - Page 18

• Manufacturer Part Number: M28W320FSU
• Description: 32Mbit (2Mb x16) and 64Mbit (4Mb x16) 3V Supply, Uniform Block, Secure Flash Memories
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M28W320FSU, M28W640FSU
STATUS REGISTER
The Status Register provides information on the
current or previous Program or Erase operation.
The various bits convey information and errors on
the operation. To read the Status register the
Read Status Register command can be issued, re-
fer to Read Status Register Command section. To
output the contents, the Status Register is latched
on the falling edge of the Chip Enable or Output
Enable signals, and can be read until Chip Enable
or Output Enable returns to V
able or Output Enable must be toggled to update
the latched data.
Bus Read operations from any address always
read the Status Register during Program and
Erase operations.
The bits in the Status Register are summarized in
Table 8., Status Register
conjunction with the following text descriptions.
Program/Erase Controller Status (Bit 7). The
Program/Erase Controller Status bit indicates
whether the Program/Erase Controller is active or
inactive. When the Program/Erase Controller Sta-
tus bit is Low (set to ‘0’), the Program/Erase Con-
troller is active; when the bit is High (set to ‘1’), the
Program/Erase Controller is inactive, and the de-
vice is ready to process a new command.
The Program/Erase Controller Status is Low im-
mediately after a Program/Erase Suspend com-
mand is issued until the Program/Erase Controller
pauses. After the Program/Erase Controller paus-
es the bit is High.
During Program, Erase, operations the Program/
Erase Controller Status bit can be polled to find the
end of the operation. Other bits in the Status Reg-
ister should not be tested until the Program/Erase
Controller completes the operation and the bit is
High.
After the Program/Erase Controller completes its
operation the Erase Status, Program Status, V
Status and Block Lock Status bits should be tested
for errors.
Erase Suspend Status (Bit 6). The Erase Sus-
pend Status bit indicates that an Erase operation
has been suspended or is going to be suspended.
When the Erase Suspend Status bit is High (set to
‘1’), a Program/Erase Suspend command has
been issued and the memory is waiting for a Pro-
gram/Erase Resume command.
The Erase Suspend Status should only be consid-
ered valid when the Program/Erase Controller Sta-
tus bit is High (Program/Erase Controller inactive).
Bit 7 is set within 30µs of the Program/Erase Sus-
pend command being issued therefore the memo-
ry may still complete the operation rather than
entering the Suspend mode.
18/49
Bits. Refer to
IH
. Either Chip En-
Table 8.
PP
in
When a Program/Erase Resume command is is-
sued the Erase Suspend Status bit returns Low.
Erase Status (Bit 5). The Erase Status bit can be
used to identify if the memory has failed to verify
that the block has erased correctly. When the
Erase Status bit is High (set to ‘1’), the Program/
Erase Controller has applied the maximum num-
ber of pulses to the block and still failed to verify
that the block has erased correctly. The Erase Sta-
tus bit should be read once the Program/Erase
Controller Status bit is High (Program/Erase Con-
troller inactive).
Once set High, the Erase Status bit can only be re-
set Low by a Clear Status Register command or a
hardware reset. If set High it should be reset be-
fore a new Program or Erase command is issued,
otherwise the new command will appear to fail.
Program Status (Bit 4). The Program Status bit
is used to identify a Program failure. When the
Program Status bit is High (set to ‘1’), the Pro-
gram/Erase Controller has applied the maximum
number of pulses to the byte and still failed to ver-
ify that it has programmed correctly. The Program
Status bit should be read once the Program/Erase
Controller Status bit is High (Program/Erase Con-
troller inactive).
Once set High, the Program Status bit can only be
reset Low by a Clear Status Register command or
a hardware reset. If set High it should be reset be-
fore a new command is issued, otherwise the new
command will appear to fail.
V
used to identify an invalid voltage on the V
during Program and Erase operations. The V
pin is only sampled at the beginning of a Program
or Erase operation. Indeterminate results can oc-
cur if V
When the V
age on the V
when the V
pin has a voltage that is below the V
Voltage, V
gram and Erase operations cannot be performed.
Once set High, the V
Low by a Clear Status Register command or a
hardware reset. If set High it should be reset be-
fore a new Program or Erase command is issued,
otherwise the new command will appear to fail.
Program Suspend Status (Bit 2). The Program
Suspend Status bit indicates that a Program oper-
ation has been suspended. When the Program
Suspend Status bit is High (set to ‘1’), a Program/
Erase Suspend command has been issued and
the memory is waiting for a Program/Erase Re-
sume command. The Program Suspend Status
should only be considered valid when the Pro-
PP
Status (Bit 3). The V
PP
becomes invalid during an operation.
PPLK
PP
PP
PP
Status bit is High (set to ‘1’), the V
Status bit is Low (set to ‘0’), the volt-
, the memory is protected and Pro-
pin was sampled at a valid voltage;
PP
Status bit can only be reset
PP
Status bit can be
PP
Lockout
PP
pin
PP
PP