16 Mbit Concurrent SuperFlash
SST36VF1601
Data Sheet
The Chip-Erase operation is initiated by executing a six-
byte command sequence with Chip-Erase command (10H)
at address 5555H 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# Polling. See
Table 4 for the command sequence, Figure 9 for timing dia-
gram, and Figure 22 for the flowchart. Any commands
issued during the Chip-Erase operation are ignored.
‘1’. The Data# Polling is valid after the rising edge of fourth
WE# (or CE#) pulse for Program operation. For Sector-,
Block-, or Chip-Erase, the Data# Polling is valid after the
rising edge of sixth WE# (or CE#) pulse. See Figure 7 for
Data# Polling (DQ
7
) timing diagram and Figure 20 for a
flowchart. There is a 1 µs bus recovery time (T
BR
) required
before valid data can be read on the data bus. New com-
mands can be entered immediately after DQ
7
becomes
true data.
Write Operation Status Detection
The SST36VF1601 provides one hardware and two soft-
ware means to detect the completion of a Write (Program
or Erase) cycle, in order to optimize the system Write cycle
time. The hardware detection uses the Ready/Busy# (RY/
BY#) output pin. The software detection includes two status
bits: Data# Polling (DQ
7
) and Toggle Bit (DQ
6
). The End-of-
Write detection mode is enabled after the rising edge of
WE#, which initiates the internal Program or Erase opera-
tion.
The actual completion of the nonvolatile write is asynchro-
nous with the system; therefore, either a Ready/Busy# (RY/
BY#), a Data# Polling (DQ
7
) or Toggle Bit (DQ
6
) read may
be simultaneous with the completion of the Write cycle. If
this occurs, the system may possibly get an erroneous
result, i.e., valid data may appear to conflict with either DQ
7
or DQ
6
. In order to prevent spurious rejection, if an errone-
ous 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.
Toggle Bit (DQ
6
)
During the internal Program or Erase operation, any con-
secutive attempts to read DQ
6
will produce alternating 1s
and 0s, i.e., toggling between 1 and 0. When the internal
Program or Erase operation is completed, the DQ
6
bit will
stop toggling. The Toggle Bit is valid after the rising edge of
fourth WE# (or CE#) pulse for Program operation. For Sec-
tor-, Block- or Chip-Erase, the Toggle Bit is valid after the
rising edge of sixth WE# (or CE#) pulse. See Figure 8 for
Toggle Bit timing diagram and Figure 20 for a flowchart.
There is a 1 µs bus recovery time (T
BR
) required before
valid data can be read on the data bus. New commands
can be entered immediately after DQ
6
no longer toggles.
Data Protection
The SST36VF1601 provides 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.
Ready/Busy# (RY/BY#)
The SST36VF1601 includes a Ready/Busy# (RY/BY#)
output signal. RY/BY# is actively pulled low while during an
internal Erase or Program operation is in progress. RY/BY#
is an open drain output that allows several devices to be
tied in parallel to V
DD
via an external pull up resistor. RY/
BY# is high impedance whenever CE# is high or RST# is
low. There is a 1 µs bus recovery time (T
BR
) required before
valid data can be read on the data bus. New commands
can be entered immediately after RY/BY# goes high.
Hardware Block Protection
The SST36VF1601 provides a hardware block protection
which protects the outermost 4 KWord in the larger bank.
The block is protected when WP# is held low. See Figure 1
for Block-Protection location.
A user can disable block protection by driving WP# high
thus allowing erase or program of data into the protected
sectors. WP# must be held high prior to issuing the write
command and remain stable until after the entire Write
operation has completed.
Data# Polling (DQ
7
)
When the SST36VF1601 is in the internal Program opera-
tion, any attempt to read DQ
7
will produce the complement
of the true data. Once the Program operation is completed,
DQ
7
will produce true data. During internal Erase opera-
tion, any attempt to read DQ
7
will produce a ‘0’. Once the
internal Erase operation is completed, DQ
7
will produce a
©2001 Silicon Storage Technology, Inc.
S71142-06-000 11/01 373
3
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