Specifications

February 2015 IS29GL_128S_01GS_00_Rev.A GL-S MirrorBit
®
Family 19
Data Sheet
3.4 Sector Protection Methods
3.4.1 Write Protect Signal
If WP# = V
IL
, the lowest or highest address sector is protected from program or erase operations independent
of any other ASP configuration. Whether it is the lowest or highest sector depends on the device ordering
option (model) selected. If WP# = V
IH
, the lowest or highest address sector is not protected by the WP# signal
but it may be protected by other aspects of ASP configuration. WP# has an internal pull-up; when
unconnected, WP# is at V
IH
.
3.4.2 ASP
Advanced Sector Protection (ASP) is a set of independent hardware and software methods used to disable or
enable programming or erase operations, individually, in any or all sectors. This section describes the various
methods of protecting data stored in the memory array. An overview of these methods is shown in Figure 3.1.
Figure 3.1 Advanced Sector Protection Overview
Every main flash array sector has a non-volatile (PPB) and a volatile (DYB) protection bit associated with it.
When either bit is 0, the sector is protected from program and erase operations.
The PPB bits are protected from program and erase when the PPB Lock bit is 0. There are two methods for
managing the state of the PPB Lock bit, Persistent Protection and Password Protection.
The Persistent Protection method sets the PPB Lock to 1 during POR or Hardware Reset so that the PPB bits
are unprotected by a device reset. There is a command to clear the PPB Lock bit to 0 to protect the PPB bits.
Password Method
(DQ2)
Persistent Method
(DQ1)
Lock Register
(One Time Programmable)
PPB Lock Bit
1,2,3
64-bit Password
(One Time Protect)
1 = PPBs Unlocked
0 = PPBs Locked
Memory Array
Sector 0
Sector 1
Sector 2
Sector N-2
Sector N-1
Sector N
4
PPB 0
PPB 1
PPB 2
PPB N-2
PPB N-1
PPB N
Persistent
Protection Bit
(PPB)
5,6
DYB 0
DYB 1
DYB 2
DYB N-2
DYB N-1
DYB N
Dynamic
Protection Bit
(DYB)
7,8,9
7. 0 = Sector Protected,
1 = Sector Unprotected.
8. Protect effective only if corresponding PPB
is “1” (unprotected).
9. Volatile Bits: defaults to user choice upon
power-up (see ordering options).
5. 0 = Sector Protected,
1 = Sector Unprotected.
6. PPBs programmed individually,
but cleared collectively
1. Bit is volatile, and defaults to “1” on reset (to
“0” if in Password Mode).
2. Programming to “0” locks all PPBs to their
current state.
3. Once programmed to “0”, requires hardware
reset to unlock or application of the
password.
4. N = Highest Address Sector.