£
Intel Advanced+ Boot Block Flash Memory (C3)
5.0
Security Modes
5.1
Flexible Block Locking
The C3 device offers an instant, individual block-locking scheme that allows any block to be
locked or unlocked with no latency, enabling instant code and data protection.
This locking scheme offers two levels of protection. The first level allows software-only control of
block locking (useful for data blocks that change frequently), while the second level requires
hardware interaction before locking can be changed (useful for code blocks that change
infrequently).
The following sections will discuss the operation of the locking system. The term “state [abc]” will
be used to specify locking states; e.g., “state [001],” where a = value of WP#, b = bit D1 of the
Block Lock status register, and c = bit D0 of the Block Lock status register. Figure 5, “Block
Locking State Diagram” on page 27 displays all of the possible locking states.
Figure 5. Block Locking State Diagram
Locked-
Down4,5
Hardware
Locked5
Locked
Power-Up/Reset
[X01]
[011]
[011]
WP# Hardware Control
Software
Locked
Unlocked
Unlocked
[111]
[110]
[X00]
Software Block Lock (0x60/0x01) or Software Block Unlock (0x60/0xD0)
Software Block Lock-Down (0x60/0x2F)
WP# hardware control
Notes: 1. [a,b,c] represents [WP#, D1, D0]. X = Don’t Care.
2. D1 indicates block Lock-down status. D1 = ‘0’, Lock-down has not been issued to
this block. D1 = ‘1’, Lock-down has been issued to this block.
3. D0 indicates block lock status. D0 = ‘0’, block is unlocked. D0 = ‘1’, block is locked.
4. Locked-down = Hardware + Software locked.
5. [011] states should be tracked by system software to determine difference
between Hardware Locked and Locked-Down states.
Datasheet
27
INTEL [ INTEL ]
