28F640W30 NUMONYX [Numonyx B.V], 28F640W30 Datasheet - Page 71

• Manufacturer Part Number: 28F640W30
• Description: Numonyx Wireless Flash Memory (W30)
• Manufacturer: NUMONYX [Numonyx B.V]

Numonyx™ Wireless Flash Memory (W30)
13.0
13.1
November 2007
Order Number: 290702-13
Security Modes
The W30 flash memory device offers both hardware and software security features to
protect the flash memory data.
Refer to
the flash device security features. Also see
on page
Block Lock Operations
Individual instant block locking protects code and data by allowing any block to be
locked or unlocked with no latency. This locking scheme offers two levels of protection:
The following sections discuss the locking system operation. The term state [abc]
specifies locking states, such as state [001]. In this syntax:
Figure 33, “Block Locking State Diagram” on page 72
The following summarizes the locking functionality.
Block lock registers are not affected by the V
and read even if V
The locking status of each block can be set to locked, unlocked, and lock-down, as
described in the following sections. See
page
• To use the software security feature, execute the Lock Block command.
• To use the hardware security feature, execute the Lock-Down Block command and
• Software-only control of block locking (useful for frequently changed data blocks).
• Hardware interaction before locking can be changed (protects infrequently changed
• a = WP# value.
• b = block lock-down status bit D1.
• c = Block Lock status register bit D0.
• All blocks power-up in a locked state.
• Unlock commands can unlock these blocks, and lock commands can lock them
• The Lock-Down command locks a block and prevents it from being unlocked when
assert the WP# signal.
code blocks).
again.
WP# is asserted.
— Locked-down blocks can be unlocked or locked with commands as long as WP#
— When WP# is asserted, previously locked-down blocks return to lock-down.
— The lock-down status bit clears only when the flash device is reset or powered-
75.
is deasserted.
down.
Figure 33, “Block Locking State Diagram” on page 72
75.
PP
< V
PPLK
.
Figure 34, “Locking Operations Flowchart” on
Figure 34, “Locking Operations Flowchart”
PP
level. These registers can be modified
defines possible locking states.
for a state diagram of
Datasheet
71