am49lv128bm Meet Spansion Inc., am49lv128bm Datasheet - Page 20

• Manufacturer Part Number: am49lv128bm
• Description: Stacked Multi-chip Package Mcp ,128 Megabit 8 M ? 16-bit ,uniform Sector Flash Memory And 32 Mbit 2 M ? 16-bit Pseudo-static Ram With Page Mode Featuring Mirrorbit Technology,supplemental Datasheet
• Manufacturer: Meet Spansion Inc.

function and unlock bypass modes are not available
when the SecSi Sector is enabled.
The SecSi sector address space in this device is allo-
cated as follows:
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
Unless otherwise specified, the device is shipped such
that the customer may program and protect the 256-
byte SecSi sector.
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
18
000000h–000007h
000008h–00007Fh
Address Range
SecSi Sector
Table 3. SecSi Sector Contents
Determined by
Customer
Lockable
customer
ESN Factory
Unavailable
Locked
ESN
Factory Locked
ExpressFlash
Determined by
determined by
customer
customer
ESN or
Am49LV128BM
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:
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.
Factory Locked: SecSi Sector Programmed and
Protected At the Factory
In devices with an ESN, the SecSi Sector is protected
when the device is shipped from the factory. The SecSi
Sector cannot be modified in any way. An ESN Factory
Locked device has an 16-byte random ESN at ad-
dresses 000000h–000007h. Please contact your local
AMD sales representative for details on ordering ESN
Factory Locked devices.
Customers may opt to have their code programmed by
AMD through the AMD ExpressFlash service (Express
Flash Factory Locked). The devices are then shipped
from AMD’s factory with the SecSi Sector permanently
locked. Contact an AMD representative for details on
using AMD’s ExpressFlash service.
Note: MCP devices with second supplier pSRAM
have 000000h address programmed to 0000h data.
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 V
allows 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.
June 17, 2004
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