Specifications

February 2015 IS29GL_128S_01GS_00_Rev.A GL-S MirrorBit
®
Family 21
Data Sheet
3.4.6 Sector Protection States Summary
Each sector can be in one of the following protection states:
 Unlocked – The sector is unprotected and protection can be changed by a simple command. The
protection state defaults to unprotected after a power cycle or hardware reset.
 Dynamically Locked – A sector is protected and protection can be changed by a simple command. The
protection state is not saved across a power cycle or hardware reset.
 Persistently Locked – A sector is protected and protection can only be changed if the PPB Lock Bit is set to
1. The protection state is non-volatile and saved across a power cycle or hardware reset. Changing the
protection state requires programming or erase of the PPB bits.
3.4.7 Lock Register
The Lock Register holds the non-volatile OTP bits for controlling protection of the SSR, and determining the
PPB Lock bit management method (protection mode).
The Secure Silicon Region (SSR) protection bits must be used with caution, as once locked, there is no
procedure available for unlocking the protected portion of the Secure Silicon Region and none of the bits in
the protected Secure Silicon Region memory space can be modified in any way. Once the Secure Silicon
Region area is protected, any further attempts to program in the area will fail with status indicating the area
being programmed is protected. The Region 0 Indicator Bit is located in the Lock Register at bit location 0 and
Region 1 in bit location 6.
As shipped from the factory, all devices default to the Persistent Protection method, with all sectors
unprotected, when power is applied. The device programmer or host system can then choose which sector
protection method to use. Programming either of the following two, one-time programmable, non-volatile bits,
locks the part permanently in that mode:
 Persistent Protection Mode Lock Bit (DQ1)
 Password Protection Mode Lock Bit (DQ2)
Table 3.1 Sector Protection States
Protection Bit Values
Sector State
PPB Lock PPB DYB
1 1 1 Unprotected - PPB and DYB are changeable
1 1 0 Protected - PPB and DYB are changeable
1 0 1 Protected - PPB and DYB are changeable
1 0 0 Protected - PPB and DYB are changeable
0 1 1 Unprotected - PPB not changeable, DYB is changeable
0 1 0 Protected - PPB not changeable, DYB is changeable
0 0 1 Protected - PPB not changeable, DYB is changeable
0 0 0 Protected - PPB not changeable, DYB is changeable
Table 3.2 Lock Register
Bit Default Value Name
15-9 1 Reserved
8 0 Reserved
7 X Reserved
6 1 SSR Region 1 (Customer) Lock Bit
5 1 Reserved
4 1 Reserved
3 1 Reserved
2 1 Password Protection Mode Lock Bit
1 1 Persistent Protection Mode Lock Bit
0 0 SSR Region 0 (Factory) Lock Bit