©2014 Silicon Storage Technology, Inc.

DS20005053B

04/14

10

4 Mbit (x16) Multi-Purpose Flash Plus

SST39VF401C / SST39VF402C / SST39LF401C / SST39LF402C

Data Sheet

Data Protection

The SST39VF401C/402C and SST39LF401C/402C provide both hardware and software features to pro-

tect 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.

Write Inhibit Mode: Forcing OE# low, CE# high, or WE# high will inhibit the Write operation. This pre-

vents inadvertent writes during power-up or power-down.

Hardware Block Protection

The SST39VF402C/SST39LF402C support top hardware block protection, which protects the top 8

KWord block of the device. The SST39VF401C/SST39LF401C support bottom hardware block protec-

tion, which protects the bottom 8KWord block of the device. The Boot Block address ranges are

described in Table 4. Program and Erase operations are prevented on the 8 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 operations on that block.

Hardware Reset (RST#)

The RST# pin provides a hardware method of resetting the device to read array data. When the RST#

is driven high before a valid Read can take place (see Figure 18).

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 SST39VF401C/402C and SST39LF401C/402C provide the JEDEC approved Software Data Pro-

tection scheme for all data alteration operations, 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 7 for

Table 4: Boot Block Address Ranges

Product

Address Range

Bottom Boot Block

SST39VF401C/SST39LF401C

00000H - 01FFFH

Top Boot Block

SST39VF402C/SST39LF402C

3E000H - 3FFFFH

T4.0 25053