NP8P128A13BSM60E Datasheet, PDF (31/92 Pages) Numonyx B.V – 128-Mbit Parallel Phase Change Memory

Numonyx® Omneo™ P8P Datasheet
Table 13: Block Locking Truth Table
V_PP
≤ V_PPLK
> V_PPLK
> V_PPLK
WP#
V_IH
V_IL
V_IH
RST#
V_IH
V_IH
V_IH
Block Write Protection
Block Lock Bits
All blocks write/erase protected
All Lock-Down and Locked
blocks write/erase protected
All Lock-Down and Locked
blocks write/erase protected
All Lock-Down block states may be
changed
Lock-Down block states may not be
changed
All Lock-Down block states may be
changed
10.1.3
Unlock Block
The Unlock Block command unlocks locked blocks (if block isn’t locked-down) so they
can be programmed or erased. Unlocked blocks return to the locked state at device
reset or power-down.
10.1.4
Lock-Down Block
Locked-down blocks (state 3 or [011]) are protected from write and erase operations
(just like locked blocks), but software commands alone cannot change their protection
state. When WP# is V_IH, the lock-down function is disabled (state 7 or [111]), and an
Unlock command (60h/D0h) must be issued to unlocked locked-down block (state 6 or
[110]), prior to modifying data in these blocks. To return an unlocked block to locked-
down state, a Lock command (60h/01h) must be issued prior to changing WP# to V_IL
(state 7 or [111] and then state 3 or [011]). A locked or unlocked block can be locked-
down by writing the Lock-Down Block command sequence. Locked-down blocks revert
to the locked state at device reset or power-down.
10.1.5
WP# Lock-Down Control
WP# = V_IH overrides the block lock-down. See Table 13, “Block Locking Truth Table” on
page 30. The WP# signal controls the lock-down function. WP# = 0 protects lock-down
blocks [011] from write, erase, and lock status changes. When WP# = 1, the lock-
down function is disabled [111] and a software command can individually unlock
locked-down blocks [110] so they can be erased and written. When the lock-down
function is disabled, locked-down blocks remain locked, and must first be unlocked by
writing the Unlock command prior to modifying data in these blocks. These blocks can
then be re-locked [111] and unlocked [110] while WP# remains high.
When WP# goes low, blocks in re-locked state [111] returns to locked-down state
[011]. However, WP# going low changes blocks at unlocked state [110] to [010] or
“virtual lock-down” state. When the lock status of a “virtual lock-down” blocks is read,
it appears to be a “locked-down” state to user when WP# is V_IL. Blocks in “virtual lock-
down” will be immediately unlocked when WP# is V_IH. Therefore, to avoid “virtual lock-
down”, a Lock command must be issued to an unlocked block prior to WP# going low.
Device reset or power-down resets all blocks to the locked state[101] or [001],
including locked-down blocks.
10.1.6
Block Lock Status
Every block’s lock status can be read in the device’s read identifier mode. To enter this
mode, write 90h to the device. Subsequent reads at Block base-address + 00002h
output that block’s lock status. Data bits DQ₀ and DQ₁ represent the lock status. DQ₀
indicates the block lock/unlock state as set by the Lock command and cleared by the
Unlock command. It is also automatically set when entering Lock-Down. DQ₁ indicates
lock-down state as set by the Lock-Down command. It cannot be cleared by software,
only by device reset or power-down. See Table 14, “Block Locking State Transitions” on
page 32.
July 2010
316144-07
31