Datasheet
©2011 Silicon Storage Technology, Inc. DS25008A 08/11
10
64 Mbit Multi-Purpose Flash Plus
SST39VF6401B / SST39VF6402B
Not Recommended for New Designs
A
Microchip Technology Company
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 15).
The Erase or Program operation that has been interrupted needs to be reinitiated after the device
resumes normal operation mode to ensure data integrity.
Software Data Protection (SDP)
The SST39VF640xB provide the JEDEC approved Software Data Protection scheme for all data alter-
ation 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 opti-
mal 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 command sequence.
Common Flash Memory Interface (CFI)
The SST39VF640xB also contain the CFI information to describe the characteristics of the device. In
order to enter the CFI Query mode, the system must write three-byte sequence, same as product ID
entry command with 98H (CFI Query command) to address 555H in the last byte sequence. 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.