參數(shù)資料
型號(hào)： SST28VF040A-200
廠商： Silicon Storage Technology, Inc.
英文描述： 4 Mbit (512K x8) SuperFlash EEPROM
中文描述： 4兆位（為512k × 8）超快閃EEPROM的
文件頁(yè)數(shù)： 3/24頁(yè)
文件大小： 323K
代理商： SST28VF040A-200
Data Sheet
4 Mbit SuperFlash EEPROM
SST28SF040A / SST28VF040A
3
2001 Silicon Storage Technology, Inc.
S71077-04-000
6/01
310
The Read operation of the SST28SF/VF040A are con-
trolled by OE# and CE# at logic low. When CE # is high,
the chip is deselected and only standby power will be 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 CE# or OE# are high.
Read-ID operation
The Read-ID operation is initiated by writing a single com-
mand (90H). A read of address 0000H will output the man-
ufacturer
’
s ID (BFH). A read of address 0001H will output
the device ID (04H). Any other valid command will termi-
nate this operation.
Data Protection
In order to protect the integrity of nonvolatile data storage,
the SST28SF/VF040A provide both
hardware and software features to prevent inadvertent
writes to the device, for example, during system power-up
or power-down. Such provisions are described below.
Hardware Data Protection
The SST28SF/VF040A are designed with hardware fea-
tures to prevent inadvertent writes. This is done in the fol-
lowing ways:
1. Write Cycle Inhibit Mode: OE# low, CE#, or WE#
high will inhibit the Write operation.
2. Noise/Glitch Protection: A WE# pulse width of less
than 5 ns will not initiate a Write cycle.
3. V
DD
Power Up/Down Detection: The Write opera-
tion is inhibited when V
DD
is less than 2.0V.
4. After power-up, the device is in the Read mode
and the device is in the Software Data Protect
state.
Software Data Protection (SDP)
The SST28SF/VF040A have software methods to further
prevent inadvertent writes. In order to perform an Erase or
Program operation, a two-step command sequence con-
sisting of a set-up command followed by an execute com-
mand avoids inadvertent erasing and programming of the
device.
The SST28SF/VF040A will default to Software Data Pro-
tection after power up. A sequence of seven consecutive
reads at specific addresses will unprotect the device The
address sequence is 1823H, 1820H, 1822H, 0418H,
041BH, 0419H, 041AH. The address bus is latched on the
rising edge of OE# or CE#, whichever occurs first. A similar
seven read sequence of 1823H, 1820H, 1822H, 0418H,
041BH, 0419H, 040AH will protect the device. Also refer to
Figures 10 and 11 for the 7 read cycle sequence Software
Data Protection. The I/O pins can be in any state (i.e., high,
low, or tri-state).
Write Operation Status Detection
The SST28SF/VF040A provide three means to detect the
completion of a Write operation, in order to optimize the
system Write operation. The end of a Write operation
(Erase or Program) can be detected by three means: 1)
monitoring the Data# Polling bit, 2) monitoring the Toggle
bit, or 3) by two successive reads of the same data. These
three detection mechanisms are described below.
The actual completion of the nonvolatile Write is asynchro-
nous 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 system may possibly
get an erroneous result, i.e., valid data may appear to con-
flict with the DQ used. In order to prevent spurious rejec-
tion, 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 completed the Write cycle, otherwise the rejec-
tion is valid.
Data# Polling (DQ
7
)
The SST28SF/VF040A feature Data# Polling to indicate
the Write operation status. During a Write operation, any
attempt to read the last byte loaded during the byte-load
cycle will receive the complement of the true data on DQ
7
.
Once the Write cycle is completed, DQ
7
will show true
data. The device is then ready for the next operation. See
Figure 12 for Data# Polling timing waveforms. In order for
Data# Polling to function correctly, the byte being polled
must be erased prior to programming.
Toggle Bit (DQ
6
)
An alternative means for determining the Write operation
status is by monitoring the Toggle Bit, DQ
6
. During a Write
operation, consecutive attempts to read data from the
device will result in DQ
6
toggling between logic 0 (low) and
logic 1 (high). When the Write cycle is completed, the tog-
gling will stop. The device is then ready for the next opera-
tion. See Figure 13 for Toggle Bit timing waveforms.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SST28VF040A-200-4C-EH 功能描述:電可擦除可編程只讀存儲(chǔ)器 512K X 8 200ns RoHS:否 制造商:Atmel 存儲(chǔ)容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時(shí)鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8
SST28VF040A-200-4C-EHE 功能描述:電可擦除可編程只讀存儲(chǔ)器 512K X 8 200ns RoHS:否 制造商:Atmel 存儲(chǔ)容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時(shí)鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8
SST28VF040A-200-4C-NH 功能描述:電可擦除可編程只讀存儲(chǔ)器 512K X 8 200ns RoHS:否 制造商:Atmel 存儲(chǔ)容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時(shí)鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8
SST28VF040A-200-4C-NHE 功能描述:電可擦除可編程只讀存儲(chǔ)器 512K X 8 200ns RoHS:否 制造商:Atmel 存儲(chǔ)容量:2 Kbit 組織:256 B x 8 數(shù)據(jù)保留:100 yr 最大時(shí)鐘頻率:1000 KHz 最大工作電流:6 uA 工作電源電壓:1.7 V to 5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8
SST28VF040A-200-4C-PH 制造商:SST 制造商全稱:Silicon Storage Technology, Inc 功能描述:4 Mbit (512K x8) SuperFlash EEPROM
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