AM70PDL127BDH Datasheet, PDF (92/128 Pages) SPANSION – 2 x 64 Megabit (8 M x 16-Bit) CMOS 3.0 Volt-Only Page Mode Flash Memory Data Storage 128 Megabit (8 M x 16-Bit) CMOS

ADVANCE INFORMATION
SecSi (Secured Silicon) Sector Flash
Memory Region
The SecSi (Secured Silicon) Sector feature provides a
Flash memory region that enables permanent part
identification through an Electronic Serial Number
(ESN). The SecSi Sector is 128 words in length, and
uses a SecSi Sector Indicator Bit (DQ7) to indicate
whether or not the SecSi Sector is locked when
shipped from the factory. This bit is permanently set at
the factory and cannot be changed, which prevents
cloning of a factory locked part. This ensures the secu-
rity of the ESN once the product is shipped to the field.
AMD offers the device with the SecSi Sector either
factory locked or customer lockable. The fac-
tory-locked version is always protected when shipped
from the factory, and has the SecSi (Secured Silicon)
Sector Indicator Bit permanently set to a “1.” The cus-
tomer-lockable version is shipped with the SecSi Sec-
tor unprotected, allowing customers to program the
sector after receiving the device. The customer-lock-
able version also has the SecSi Sector Indicator Bit
permanently set to a “0.” Thus, the SecSi Sector Indi-
cator Bit prevents customer-lockable devices from
being used to replace devices that are factory locked.
The SecSi sector address space in this device is allo-
cated as follows:
Table 4. SecSi Sector Contents
SecSi Sector
Address
Range
x16
000000h–
000007h
000008h–
00007Fh
Standard
Factory
Locked
ESN
Unavailable
ExpressFlash
Factory Locked
ESN or determined
by customer
Determined
by customer
Customer
Lockable
Determined by
customer
The system accesses the SecSi Sector through a
command sequence (see “Enter SecSi Sector/Exit
SecSi Sector Command Sequence”). After the system
has written the Enter SecSi Sector command se-
quence, it may read the SecSi Sector by using the ad-
dresses normally occupied by the first sector (SA0).
This mode of operation continues until the system is-
sues the Exit SecSi Sector command sequence, or
until power is removed from the device. On power-up,
or following a hardware reset, the device reverts to
sending commands to sector SA0.
Customer Lockable: SecSi Sector NOT
Programmed or Protected At the Factory
As an alternative to the factory-locked version, the de-
vice may be ordered such that the customer may pro-
gram and protect the 128-word SecSi sector. See
Table 5 for SecSi Sector addressing.
The system may program the SecSi Sector using the
write-buffer, accelerated and/or unlock bypass meth-
ods, in addition to the standard programming com-
mand sequence. See Command Definitions.
Programming and protecting the SecSi Sector must be
used with caution since, once protected, there is no
procedure available for unprotecting the SecSi Sector
area and none of the bits in the SecSi Sector memory
space can be modified in any way.
The SecSi Sector area can be protected using one of
the following procedures:
■ Write the three-cycle Enter SecSi Sector Region-
command sequence, and then follow the in-system
sector protect algorithm as shown in Figure 2, ex-
cept that RESET# may be at either VIH or VID. This al-
lows in-system protection of the SecSi Sector
without raising any device pin to a high voltage.
Note that this method is only applicable to the SecSi
Sector.
■ To verify the protect/unprotect status of the SecSi
Sector, follow the algorithm shown in Figure 3.
Once the SecSi Sector is programmed, locked and
verified, the system must write the Exit SecSi Sector
Region command sequence to return to reading and
writing within the remainder of the array.
START
RESET# =
V_IH or V_ID
Wait 1 µs
Write 60h to
any address
Write 40h to SecSi
Sector address
with A6 = 0,
A1 = 1, A0 = 0
Read from SecSi
Sector address
with A6 = 0,
A1 = 1, A0 = 0
If data = 00h,
SecSi Sector is
unprotected.
If data = 01h,
SecSi Sector is
protected.
Remove V_IH or V_ID
from RESET#
Write reset
command
SecSi Sector
Protect Verify
complete
Figure 3. SecSi Sector Protect Verify
90
Am70PDL127BDH/Am70PDL129BDH
November 25, 2003