RC28F256 Intel Corporation, RC28F256 Datasheet - Page 72

• Manufacturer Part Number: RC28F256
• Description: Intel StrataFlash Embedded Memory
• Manufacturer: Intel Corporation

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1-Gbit P30 Family
13.3
April 2005
72
Protection Registers
The device contains 17 Protection Registers (PRs) that can be used to implement system security
measures and/or device identification. Each Protection Register can be individually locked.
The first 128-bit Protection Register is comprised of two 64-bit (8-word) segments. The lower 64-
bit segment is pre-programmed at the Intel factory with a unique 64-bit number. The other 64-bit
segment, as well as the other sixteen 128-bit Protection Registers, are blank. Users can program
these registers as needed. When programmed, users can then lock the Protection Register(s) to
prevent additional bit programming (see
The user-programmable Protection Registers contain one-time programmable (OTP) bits; when
programmed, register bits cannot be erased. Each Protection Register can be accessed multiple
times to program individual bits, as long as the register remains unlocked.
Each Protection Register has an associated Lock Register bit. When a Lock Register bit is
programmed, the associated Protection Register can only be read; it can no longer be programmed.
Additionally, because the Lock Register bits themselves are OTP, when programmed, Lock
Register bits cannot be erased. Therefore, when a Protection Register is locked, it cannot be
unlocked.
Intel StrataFlash
Order Number: 306666, Revision: 001
®
Embedded Memory (P30)
Figure 33, “Protection Register Map” on page
Datasheet
73).