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參數資料
| 型號： | STK1744 |
| 廠商： | Electronic Theatre Controls, Inc. |
| 英文描述： | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
| 中文描述： | 32K的× 8自動存儲非易失實時時鐘 |
| 文件頁數： | 7/12頁 |
| 文件大?。?/td> | 315K |
| 代理商： | STK1744 |
STK1744
January 2003
7
Document Control # ML0020 rev 0.0
The STK1744 is a 32K x 8 nonvolatile static
RAM
with a full-function real-time clock (
RTC
). Nonvolatile
data is preserved in integral
QuantumTrap
Nonvol-
atile Elements and is
not subject to battery failure or
capacitor discharge. The real-time clock registers
reside in the eight uppermost
RAM
locations, and
contain century, year, month, date, day, hour, minute
and second data in 24-hour
BCD
format. Corrections
for the day of the month and leap years are made
automatically. This nonvolatile time-keeping
RAM
is
functionally similar to any
JEDEC
standard 32K x 8
SRAM
.
The
RTC
registers are double-buffered to avoid
access of incorrect data that could otherwise occur
during clock update cycles. The double-buffered
system prevents time loss by maintaining internal
clock operation while time register data is accessed.
The STK1744 contains integral power-fail circuitry
that deselects the device when V
CC
drops below
V
SWITCH
.
The STK1744 is a pin-compatible replacement for
the ST Microelectronics M48T35 and the Dallas
Semiconductor DS1744, but without the limitations
of an embedded lithium battery. The Simtek module
uses a double-layer high-value capacitor to maintain
RTC
operation on every power down for at least 30
days. The part can be soldered directly onto printed
circuit boards and handled without concern for dam-
aging or discharging internal batteries. Unlike some
other
RTC
s, the STK1744 is Year 2000-compliant.
NOISE CONSIDERATIONS
Note that the STK1744 is a high-speed memory and
so must have a high-frequency bypass capacitor of
approximately 0.1
μ
F connected between V
CC
and
V
SS
, using leads and traces that are as short as pos-
sible. As with all high-speed
CMOS
ICs, normal care-
ful routing of power, ground and signals will help
prevent noise problems.
SRAM AND RTC READ
The STK1744 performs a
READ
cycle whenever E
and G are low and W is high. The address specified
on pins A
0-14
determines which of the 32,760 data
bytes or 8
RTC
registers will be accessed. When the
READ
is initiated by an address transition, the out-
puts will be valid after a delay of t
AVQV
(
READ
cycle
#1). If the
READ
is initiated by E or G, the outputs will
be valid at t
ELQV
or at t
GLQV
, whichever is later (
READ
cycle #2). The data outputs will repeatedly respond to
address changes within the t
AVQV
access time without
the need for transitions on any control input pins, and
will remain valid until another address change or until
E or G is brought high or W is brought low.
Note that the eight most significant bytes of the
address space are reserved for accessing the
RTC
registers, as shown in the
RTC
Register Map.
While the double-buffered
RTC
register structure
reduces the chance of reading incorrect data from the
clock, the user should halt internal updates to the
DEVICE OPERATION
RTC REGISTER MAP
ADDRESS
(HEXADECIMAL)
BCD DATA
FUNCTION/RANGE
D7
D6
D5
D4
D3
D2
D1
D0
7FF8
W
R
10 Centuries
Centuries
Centuries: 00 - 39, Control
7FF9
X
10 Seconds
Seconds
Seconds: 00 - 59
7FFA
X
10 Minutes
Minutes
Minutes:
00 - 59
7FFB
X
X
10 Hours
Hours
Hours:
00 - 23
7FFC
1
FT
X
X
X
Days
Days:
01 - 07
7FFD
X
X
10 Dates
Dates
Dates:
01 - 31
7FFE
X
X
X
10 Mos.
Months
Months:
01 - 12
7FFF
10 Years
Years
Years:
00 - 99
Key:
R = Read Bit
W = Write Bit
1
= Battery Flag high (there is no battery to fail)
FT = Frequency test bit
X = Don’t Care
相關PDF資料 |
PDF描述 |
|---|---|
| STK1744-D25 | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
| STK1744-D25I | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
| STK1744-D35 | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
| STK1744-D35I | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
| STK1744-D45 | 32K x 8 AutoStore nvSRAM with Real-Time Clock |
相關代理商/技術參數 |
參數描述 |
|---|---|
| STK17T88-RF25 | 功能描述:NVRAM 32Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 數據總線寬度:8 bit 存儲容量:1024 Kbit 組織:128 K x 8 接口類型:Parallel 訪問時間:70 ns 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 工作電流:85 mA 最大工作溫度:+ 70 C 最小工作溫度:0 C 封裝 / 箱體:EDIP 封裝:Tube |
| STK17T88-RF25I | 功能描述:NVRAM 32Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 數據總線寬度:8 bit 存儲容量:1024 Kbit 組織:128 K x 8 接口類型:Parallel 訪問時間:70 ns 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 工作電流:85 mA 最大工作溫度:+ 70 C 最小工作溫度:0 C 封裝 / 箱體:EDIP 封裝:Tube |
| STK17T88-RF25ITR | 功能描述:NVRAM 32Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 數據總線寬度:8 bit 存儲容量:1024 Kbit 組織:128 K x 8 接口類型:Parallel 訪問時間:70 ns 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 工作電流:85 mA 最大工作溫度:+ 70 C 最小工作溫度:0 C 封裝 / 箱體:EDIP 封裝:Tube |
| STK17T88-RF25TR | 功能描述:NVRAM 32Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 數據總線寬度:8 bit 存儲容量:1024 Kbit 組織:128 K x 8 接口類型:Parallel 訪問時間:70 ns 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 工作電流:85 mA 最大工作溫度:+ 70 C 最小工作溫度:0 C 封裝 / 箱體:EDIP 封裝:Tube |
| STK17T88-RF45 | 功能描述:NVRAM 32Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 數據總線寬度:8 bit 存儲容量:1024 Kbit 組織:128 K x 8 接口類型:Parallel 訪問時間:70 ns 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 工作電流:85 mA 最大工作溫度:+ 70 C 最小工作溫度:0 C 封裝 / 箱體:EDIP 封裝:Tube |
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