©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.
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 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#
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 18).
The Erase or Program operation that has been interrupted needs to be re-initiated after the device
resumes nor mal 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
©2014 Silicon Storage Technology, Inc. DS20005053B 04/14
11
4 Mbit (x16) Multi-Purpose Flash Plus
SST39VF401C / SST39VF402C / SST39LF401C / SST39LF402C
Data Sheet
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 command sequence.
Common Flash Memory Interface (CFI)
The SST39VF401C/402C and SST39LF401C/402C also contain the CFI information to describe the
characteristics of the device. In order to enter the CFI Query mode, the system wr ites a three-byte
sequence, same as product ID entry command with 98H (CFI Query command) to address 555H in
the last byte sequence. Additionally, the system can use the one-byte sequence with 55H on the
Address and 89H on the Data Bus to enter the CFI Query mode. Once the device enters the CFI
Query mode, the system can read CFI data at the addresses given in Tables 8 through 10. The system
must write the CFI Exit command to return to Read mode from the CFI Query mode.
Product Identification
The Product Identification mode identifies the devices as the SST39VF401C / SST39VF402C /
SST39LF401C / SST39LF402C, and manufacturer as Microchip. This mode may be accessed soft-
ware operations. Users may use the Software Product Identification operation to identify the part (i.e.,
using the device ID) when using multiple manufacturers in the same socket. For details, see Table 7 for
software operation, Figure 14 for the Software ID Entry and Read timing diagram and Figure 24 for the
Software ID Entry command sequence flowchart.
Product Identification Mode Exit/CFI Mode Exit
In order to return to the standard Read mode, the Software Product Identification mode must be exited.
Exit is accomplished by issuing the Software ID Exit command sequence, which returns the device to
the Read mode. This command may also be used to reset the device to the Read mode after any inad-
vertent transient condition that apparently causes the device to behave abnormally, e.g., not read cor-
rectly. Please note that the Software ID Exit/CFI Exit command is ignored during an internal Program
or Erase operation. See Table 7 for software command codes, Figure 16 for timing waveform, and Fig-
ure 25 for flowcharts.
Table 5: Product Identification
Address Data
Manufacturer’s ID 0000H BFH
Device ID
SST39VF401C/SST39LF401C 0001H 2321H
SST39VF402C/SST39LF402C 0001H 2322H
T5.2 25053
©2014 Silicon Storage Technology, Inc. DS20005053B 04/14
12
4 Mbit (x16) Multi-Purpose Flash Plus
SST39VF401C / SST39VF402C / SST39LF401C / SST39LF402C
Data Sheet
Security ID
The SST39VF401C/402C and SST39LF401C/402C devices offer a 136 Word Security ID space. The
Secure ID space is divided into two segments—one factory programmed segment and one user pro-
grammed segment. The first segment is programmed and locked at the factory with a random 128-bit
number. The user segment, with a 128 word space, is left un-programmed for the customer to program
as desired.
To program the user segment of the Security ID, the user must use the Security ID Word-Program
command. To detect end-of-write for the SEC ID, read the toggle bits. Do not use Data# Polling. Once
this is complete, the Sec ID should be locked using the User Sec ID Program Lock-Out. This disables
any future corruption of this space. Note that regardless of whether or not the Sec ID is locked, neither
Sec ID segment can be erased.
The Secure ID space can be queried by executing a three-byte command sequence with Enter Sec ID
command (88H) at address 555H in the last byte sequence. To exit this mode, the Exit Sec ID com-
mand should be executed. Refer to Table 7 for more details.

SST39VF401C-70-4C-MAQE

Mfr. #:
Manufacturer:
Microchip Technology
Description:
NOR Flash 2.7V to 3.6V 4Mbit Multi-Purpose Flash
Lifecycle:
New from this manufacturer.
Delivery:
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