2
Data Sheet
512 Kbit / 1 Mbit / 2 Mbit / 4 Mbit Small-Sector Flash
SST29SF512 / SST29SF010 / SST29SF020 / SST29SF040
SST29VF512 / SST29VF010 / SST29VF020 / SST29VF040
©2005 Silicon Storage Technology, Inc. S71160-11-000 3/05
Device Operation
Commands are used to initiate the memory operation func-
tions of the device. Commands are written to the device
using standard microprocessor write sequences. A com-
mand is written by asserting WE# low while keeping CE#
low. The address b us is latched on the falling edge of WE#
or CE#, whichever occurs last. The data bus is latched on
the rising edge of WE# or CE#, whiche v er o ccurs first.
Read
The Read operation of the SST29SF512/0x0 and
SST29VF512/0x0 de vices are controlled b y CE# and OE#,
both have to be low for the system to obtain data from the
outputs. CE# is used for device selection. When CE# is
high, the chip is deselected and only standb y pow er is con-
sumed. OE# is the output control and is used to gate data
from the output pins. The data bus is in high impedance
state when either CE# or OE# is high. Refer to the Read
cycle timing diagr am f or further details (Figure 3).
Byte-Program Operation
The SST29SF512/0x0 and SST29VF512/0x0 devices are
programmed on a byte-by-byte basis. Before program-
ming, the sector wher e the byte e xists must be fully erased.
The Program operation is accomplished in three steps. The
first step is the three-b yte load sequence for Software Data
Protection. The second step is to load byte address and
byte data. During the Byte-Program operation, the
addresses are latched on the falling edge of either CE# or
WE#, whiche v er occurs last . The data is latched on the ris-
ing edge of either CE# or WE#, whiche v er occurs first . The
third step is the internal Program operation which is initi-
ated after the rising edge of the f ourth WE# or CE#, which-
e ver occurs fir st. The Program oper ation, once initiated, will
be completed, within 20 µs. See Figures 4 and 5 for WE#
and CE# controlled Program operation timing diagrams
and Figure 15 for flowcharts. During the Program opera-
tion, the only valid reads are Data# Polling and Toggle Bit.
During the internal Program operation, the host is free to
perf orm additional tasks. An y commands written during the
internal Program operation will be ignored.
Sector-Erase Operation
The Sector-Erase oper ation allows the system to er ase the
device on a sector-by-sector basis. The SST29SF512/0x0
and SST29VF512/0x0 offer Sector-Erase mode. The sec-
tor architecture is based on uniform sector size of 128
Bytes. The Sector-Erase operation is initiated by executing
a six-byte command sequence with Sector-Erase com-
mand (20H) and sector address (SA) in the last bus cycle.
The sector address is latched on the falling edge of the
sixth WE# pulse, while the command (20H) is latched on
the rising edge of the sixth WE# pulse. The internal Erase
operation begins after the sixth WE# pulse. The End-of-
Erase operation can be determined using either Data#
Polling or Toggle Bit methods. See Figure 8 for timing
waveforms. Any commands issued during the Sector-
Erase operat ion are ignored.
Chip-Erase Operation
The SST29SF512/0x0 and SST29VF512/0x0 devices pro-
vide a Chip-Erase operation, which allows the user to
erase the entire memory arra y to the “1s” state. Th is is use-
ful when the entire d e vice must be quic kly er ased.
The Chip-Erase operation is initiated by executing a six-
byte Software Data Protection command sequence with
Chip-Erase command (10H) with address 555H in the last
byte sequence. The internal Erase operation begins with
the rising edge of the sixth WE# or CE#, whichev er occurs
first. During the internal Erase oper ation, the only valid read
is Toggle Bit or Dat a# P olling. See Table 4 for the comman d
sequence, Figure 9 for timing diagram, and Figure 18 for
the flowchart. Any commands written during the Chip-
Erase operation will be ignored.
Write Operation Status Detection
The SST29SF512/0x0 and SST29VF512/0x0 devices
provide two softw are means to detect the completion of a
Write (Program or Erase) cycle, in order to optimize the
system Write cycle time. The softw are detection includes
two status bits: Data# P olling (DQ7) and Toggle Bit (DQ6).
The End-of-Write detection mode is enabled after the ris-
ing edge of WE# which initiates the inter nal Program or
Erase operation.
The actual completion of the nonvolatile write is asyn-
chronous with the system; therefore, either a Data# Poll-
ing or Toggle Bit read may be simultaneous with the
completion of the Write cycle. If this occurs, the system
ma y possib ly get an erroneous result, i.e., valid data may
appear to conflict with either DQ7 or DQ6. In order to pre-
vent 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 comp lete d the Write
cycle, otherwise the rejection is valid.