S29CD-G Datasheet, PDF (35/87 Pages) SPANSION – 32 Megabit (1M x 32-Bit), 16 Megabit (512K x 32-Bit) 2.5 Volt-only Burst Mode, Dual Boot, Simultaneous Read/ Write Flash Memory with VersatileI/O

Preliminary
Table 34. Configuration Register After Device Reset
CR15
RM
1
CR14
Reserve
0
CR13
IAD3
0
CR12
IAD2
1
CR11
IAD1
1
CR10
IAD0
1
CR9
DOC
0
CR8
WC
0
CR7
BS
1
CR6
CC
1
CR5
Reserve
0
CR4
Reserve
0
CR3
Reserve
0
CR2
BL2
1
CR1
BL1
0
CR0
BL0
0
Initial Access Delay Configuration
The frequency configuration informs the device of the number of clocks that must elapse after
ADV# is driven active before data is available. This value is determined by the input clock
frequency.
Sector Protection
The device features several levels of sector protection, which can disable both the program and
erase operations in certain sectors or sector groups
Sector and Sector Groups
The distinction between sectors and sector groups is fundamental to sector protection. Sector are
individual sectors that can be individually sector protected/unprotected. These are the outermost
4 Kword boot sectors, that is, SA0 to SA7 and SA70 to SA77. See Table 35 on page 35, Table 23
on page 19, Table 24 on page 20, Table 25 on page 21, and Table 26 on page 22.
Sector groups are a collection of three or four adjacent 32 kword sectors. For example, sector
group SG8 is comprised of sector SA8 to SA10. When any sector in a sector group is protected/
unprotected, every sector in that group is protection/unprotected. See Table 35, Table 23,
Table 24, Table 25, and Table 26.
Persistent Sector Protection
A command sector protection method that replaces the old 12 V controlled protection method.
Password Sector Protection
A highly sophisticated protection method that requires a password before changes to certain sec-
tors or sector groups are permitted.
WP# Hardware Protection
A write protect pin that can prevent program or erase to the two outermost 8 Kbytes sectors in
the 75% bank.
All parts default to operate in the Persistent Sector Protection mode. The customer must then
choose if the Persistent or Password Protection method is most desirable. There are two one-time
programmable non-volatile bits that define which sector protection method is used. If the cus-
tomer decides to continue using the Persistent Sector Protection method, they must set the
Persistent Sector Protection Mode Locking Bit. This permanently sets the part to operate
only using Persistent Sector Protection. If the customer decides to use the password method, they
must set the Password Mode Locking Bit. This permanently sets the part to operate only using
password sector protection.
It is important to remember that setting either the Persistent Sector Protection Mode Lock-
ing Bit or the Password Mode Locking Bit permanently selects the protection mode. It is not
possible to switch between the two methods once a locking bit is set. It is important that one
mode is explicitly selected when the device is first programmed, rather than relying on
November 14, 2005 S29CD-G_00_B0
S29CD-G Flash Family
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