Numonyx™ Wireless Flash Memory (W18)
13.1.4
Block Lock Status
Every block’s lock status can be read in read identifier mode. To enter this mode, issue
the Read Identifier command to the device. Subsequent reads at BBA + 02h will output
that block’s lock status. For example, to read the block lock status of block 10, the
address sent to the device should be 50002h (for a top-parameter device). The lowest
two data bits of the read data, DQ1 and DQ0, represent the lock status. DQ0 indicates
the block lock status. It is set by the Lock Block command and cleared by the Block
Unlock command. It is also set when entering the lock-down state. DQ1 indicates lock-
down status and is set by the Lock-Down command. The lock-down status bit cannot be
cleared by software–only by device reset or power-down. See
Table 28: Write Protection Truth Table
VPP
X
V
IL
X
X
WP#
X
X
V
IL
V
IH
RST#
V
IL
V
IH
V
IH
V
IH
Write Protection
Device inaccessible
Word program and block erase prohibited
All lock-down blocks locked
All lock-down blocks can be unlocked
13.1.5
Lock During Erase Suspend
Block lock configurations can be performed during an erase suspend operation by using
the standard locking command sequences to unlock, lock, or lock-down a block. This
feature is useful when another block requires immediate updating.
To change block locking during an erase operation, first write the Erase Suspend
command. After checking SR[6] to determine the erase operation has suspended, write
the desired lock command sequence to a block; the lock status will be changed. After
completing lock, unlock, read, or program operations, resume the erase operation with
the Erase Resume command (D0h).
If a block is locked or locked-down during a suspended erase of the same block, the
locking status bits change immediately. When the erase operation is resumed, it will
complete normally.
Locking operations cannot occur during program suspend.
shows valid commands during erase suspend.
13.1.6
Status Register Error Checking
Using nested locking or program command sequences during erase suspend can
introduce ambiguity into Status Register results.
Because locking changes require 2-cycle command sequences, for example, 60h
followed by 01h to lock a block, following the Configuration Setup command (60h) with
an invalid command produces a command sequence error (SR[5:4]=11b). If a Lock
Block command error occurs during erase suspend, the device sets SR[4] and SR[5] to
1 even after the erase is resumed. When erase is complete, possible errors during the
erase cannot be detected from the Status Register because of the previous locking
command error. A similar situation occurs if a program operation error is nested within
an erase suspend.
November 2007
Order Number: 290701-18
Datasheet
73
NUMONYX [ NUMONYX B.V ]
