SST49LF008C-33-4C-NH View Datasheet(PDF) - Silicon Storage Technology
Part Name
Description
MFG CO.
SST49LF008C-33-4C-NH Datasheet PDF : 36 Pages
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4 Mbit / 8 Mbit LPC Serial Flash
SST49LF004C / SST49LF008C
Advance Information
TABLE 16: BLOCK/PDA SECTOR LOCKING REGISTER BITS
Reserved Bit
[7:3]
00000
00000
00000
00000
00000
00000
00000
00000
Read-Lock Bit
[2]
0
0
0
0
1
1
1
1
Lock-Down Bit
[1]
0
0
1
1
0
0
1
1
Write-Lock Bit
[0]
0
1
0
1
0
1
0
1
Lock Status
Full Access
Write Locked (Default State at Power-Up)
Locked Open (Full Access Locked Down)
Write Locked Down
Block Read Locked (Registers alterable)
Block Read & Write Lock (Registers alterable)
Block Read Locked Down (Registers not alterable)
Block Read & Write lock Down (Registers not alterable)
T16.0 1292
Write-Lock Bit
The Write-Lock bit, bit 0, controls the lock state described
in Table 16. The default Write status of all blocks after
power up is write locked. When bit 0 of the Block Locking
register is set, Program and Erase operations for the corre-
sponding block are prevented. Clearing the Write-Lock bit
will unprotect the block. The Write-Lock bit must be cleared
prior to starting a Program or Erase operation since it is
sampled at the beginning of the operation. The Write-Lock
bit functions in conjunction with the hardware Write Lock
pin TBL# for the top Boot Block. When TBL# is low, it over-
rides the software locking scheme. The top Boot Block
Locking register does not indicate the state of the TBL#
pin. The Write-Lock bit functions in conjunction with the
hardware WP#/AAI pin for the remaining blocks (Blocks 0
to 17 for 49LF008C and Blocks 0 to 9 for 49LF004C).
When WP#/AAI is low, it overrides the software locking
scheme. The Block Locking register does not indicate the
state of the WP#/AAI pin.
Lock-Down Bit
The Lock-Down bit, bit 1, controls the Block Locking regis-
ter as described in Table 16. When in LPC interface mode,
the default Lock Down status of all blocks upon power-up is
not locked down. Once the Lock-Down bit is set, any future
attempted changes to that Block Locking register will be
ignored. The Lock-Down bit is only cleared upon a device
reset with RST# or INIT# or power down. Current Lock
Down status of a particular block can be determined by
reading the corresponding Lock-Down bit. Once a block’s
Lock-Down bit is set, the Read-Lock and Write-Lock bits for
that block can no longer be modified: the block is locked
down in its current state of read/write accessibility.
Read-Lock Bit
The default read status of all blocks upon power-up is read-
unlocked. When a block’s read lock bit is set, data cannot
be read from that block. An attempted read from a read-
locked block will result in the data 00h. The read lock status
can be unlocked by clearing the read lock bit: this can only
be done provided that the block is not locked down. The
current read lock status of a particular block can be deter-
mined by reading the corresponding read-lock bit.
©200 Silicon Storage Technology, Inc.
23
S71292-00-000
1/06
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