©2011 Silicon Storage Technology, Inc. DS25040A 05/11
6
16 Mbit Multi-Purpose Flash Plus
SST39VF1681 / SST39VF1682
Data Sheet
Microchip Technology Company
timing waveforms and Figure 24 for the flowchart. Any commands issued during the Sector- or Block-
Erase operation are ignored. When WP# is low, any attempt to Sector- (Block-) Erase the protected
block will be ignored. During the command sequence, WP# should be statically held high or low.
Erase-Suspend/Erase-Resume Commands
The Erase-Suspend operation temporarily suspends a Sector- or Block-Erase operation thus allowing
data to be read from any memory location, or program data into any sector/block that is not suspended
for an Erase operation. The operation is executed by issuing one byte command sequence with Erase-
Suspend command (B0H). The device automatically enters read mode typically within 20 µs after the
Erase-Suspend command had been issued. Valid data can be read from any sector or block that is not
suspended from an Erase operation. Reading at address location within erase-suspended sectors/
blocks will output DQ2toggling and DQ6at “1”. While in Erase-Suspend mode, a Byte-Program opera-
tion is allowed except for the sector or block selected for Erase-Suspend.
To resume Sector-Erase or Block-Erase operation which has been suspended the system must issue Erase
Resume command. The operation is executed by issuing one byte command sequence with Erase Resume com-
mand (30H) at any address in the last Byte sequence.
Chip-Erase Operation
The SST39VF168x provide a Chip-Erase operation, which allows the user to erase the entire memory array to
the “1” state. This is useful when the entire device must be quickly erased.
The Chip-Erase operation is initiated by executing a six-byte command sequence with Chip-Erase command
(10H) at address AAAH in the last byte sequence. The Erase operation begins with the rising edge of the sixth
WE# or CE#, whichever occurs first. During the Erase operation, the only valid read is Toggle Bit or Data# Poll-
ing. See Table 6 for the command sequence, Figure 10 for timing diagram, and Figure 24 for the flowchart.
Any commands issued during the Chip-Erase operation are ignored. When WP# is low, any attempt to Chip-
Erase will be ignored. During the command sequence, WP# should be statically held high or low.
Write Operation Status Detection
The SST39VF168x provide two software means to detect the completion of a Write (Program or
Erase) cycle, in order to optimize the system write cycle time. The software detection includes two sta-
tus bits: Data# Polling (DQ7) and Toggle Bit (DQ6). The End-of-Write detection mode is enabled after
the rising edge of WE#, which initiates the internal Program or Erase operation.
The actual completion of the nonvolatile write is asynchronous with the system; therefore, either a Data#
Polling or Toggle Bit read may be simultaneous with the completion of the write cycle. If this occurs, the sys-
tem may possibly get an erroneous result, i.e., valid data may appear to conflict with either DQ7or DQ6.In
order to prevent spurious rejection, if an erroneous result occurs, the software routine should include a loop
to read the accessed location an additional two (2) times. If both reads are valid, then the device has com-
pleted the Write cycle, otherwise the rejection is valid.
Data# Polling (DQ7)
When the SST39VF168x are in the internal Program operation, any attempt to read DQ7will produce the
complement of the true data. Once the Program operation is completed, DQ7will produce true data. Note that
even though DQ7may have valid data immediately following the completion of an internal Write operation, the
remaining data outputs may still be invalid: valid data on the entire data bus will appear in subsequent succes-
sive Read cycles after an interval of 1 µs. During internal Erase operation, any attempt to read DQ7will pro-