Datasheet

4
Data Sheet
32 Mbit Multi-Purpose Flash Plus
SST39VF3201B / SST39VF3202B
©2009 Silicon Storage Technology, Inc. S71384-01-000 1/09
Data Protection
The SST39VF320xB provide both hardware and software
features to protect nonvolatile data from inadvertent writes.
Hardware Data Protection
Noise/Glitch Protection: A WE# or CE# pulse of less than 5
ns will not initiate a write cycle.
V
DD
Power Up/Down Detection: The Write operation is
inhibited when V
DD
is less than 1.5V.
Write Inhibit Mode:
Forcing OE# low, CE# high, or WE#
high will inhibit the Write operation. This prevents inadvert-
ent writes during power-up or power-down.
Hardware Block Protection
The SST39VF3202B support top hardware block protec-
tion, which protects the top 32 KWord block of the device.
The SST39VF3201B support bottom hardware block pro-
tection, which protects the bottom 32 KWord block of the
device. The Boot Block address ranges are described in
Table 2. Program and Erase operations are prevented on
the 32 KWord when WP# is low. If WP# is left floating, it is
internally held high via a pull-up resistor, and the Boot
Block is unprotected, enabling Program and Erase opera-
tions on that block.
Hardware Reset (RST#)
The RST# pin provides a hardware method of resetting the
device to read array data. When the RST# pin is held low
for at least T
RP,
any in-progress operation will terminate and
return to Read mode. When no internal Program/Erase
operation is in progress, a minimum period of T
RHR
is
required after RST# is driven high before a valid Read can
take place. See Figure 17.
The Erase or Program operation that has been interrupted
needs to be re-initiated after the device resumes normal
operation mode to ensure data integrity.
Software Data Protection (SDP)
The SST39VF320xB provide the JEDEC approved Soft-
ware Data Protection scheme for all data alteration opera-
tions, i.e., Program and Erase. Any Program operation
requires the inclusion of the three-byte sequence. The
three-byte load sequence is used to initiate the Program
operation, providing optimal protection from inadvertent
Write operations, e.g., during the system power-up or
power-down. Any Erase operation requires the inclusion of
six-byte sequence. These devices are shipped with the
Software Data Protection permanently enabled. See Table
6 for the specific software command codes. During SDP
command sequence, invalid commands will abort the
device to read mode within T
RC.
The contents of DQ
15
-DQ
8
can be V
IL
or V
IH
, but no other value, during any SDP com-
mand sequence.
Common Flash Memory Interface (CFI)
The SST39VF320xB also contain the CFI information to
describe the characteristics of the device. In order to enter
the CFI Query mode, the system must write the three-byte
sequence, same as product ID entry command with 98H
(CFI Query command) to address 555H in the last byte
sequence. The system can also enter the CFI Query
mode, by using the one-byte sequence with 55H on
Address and 98H on Data Bus. Once the device enters
the CFI Query mode, the system can read CFI data at the
addresses given in Tables 7 through 9. The system must
write the CFI Exit command to return to Read mode from
the CFI Query mode.
TABLE 2: Boot Block Address Ranges
Product Address Range
Bottom Boot Block
SST39VF3201B 000000H-007FFFH
Top Boot Block
SST39VF3202B 1F8000H-1FFFFFH
T2.0 1384