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参数资料
| 型号： | DS17285S-3NT |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/31页 |
| 文件大小： | 0K |
| 描述： | IC RTC 3V 2K NV RAM 24-SOIC |
| 标准包装： | 1,000 |
| 类型： | 时钟/日历 |
| 特点： | 警报器，夏令时，闰年，NVSRAM，方波输出 |
| 存储容量： | 2KB |
| 时间格式： | HH:MM:SS（12/24 小时） |
| 数据格式： | YY-MM-DD-dd |
| 接口： | 并联 |
| 电源电压： | 2.7 V ~ 3.7 V |
| 电压 - 电源，电池： | 2.5 V ~ 3.7 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 24-SOIC W |
| 包装： | 带卷 (TR) |
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DS17285/DS17287/DS17485/DS17487/DS17885/DS17887
Real-Time Clocks
22
____________________________________________________________________
Century Counter
A register has been added in bank 1, location 48H, to
keep track of centuries. The value is read in either bina-
ry or BCD according to the setting of the DM bit.
RTC Write Counter
An 8-bit counter located in extended register bank 1,
5Eh, counts the number of times the RTC is written to.
This counter is incremented on the rising edge of the
WR signal every time that the CS signal qualifies it. This
counter is a read-only register and rolls over after 256
RTC write pulses. This counter can be used to deter-
mine if and how many RTC writes have occurred since
the last time this register was read.
Auxiliary Battery
The VBAUX input is provided to supply power from an
auxiliary battery for the DS17x85/DS17x87 kickstart,
wake-up, and SQW output in the absence of VCC func-
tions. This power source must be available to use these
auxiliary functions when no VCC is applied to the device.
The auxiliary battery enable (ABE; bank 1, register
04BH) bit in Extended Control Register 4B is used to
turn the auxiliary battery on and off for the above func-
tions in the absence of VCC. When set to 1, VBAUX bat-
tery power is enabled; when cleared to 0, VBAUX
battery power is disabled to these functions.
In the DS17x85/DS17x87, this auxiliary battery can be
used as the primary backup power source for maintain-
ing the clock/calendar, user RAM, and extended exter-
nal RAM functions. This occurs if the VBAT pin is at a
lower voltage than VBAUX. If the DS17x85 is to be
backed up using a single battery with any auxiliary
functions enabled, then VBAUX should be used and
VBAT should be grounded. If VBAUX is not to be used, it
should be grounded and ABE should be cleared to 0.
Wake-Up/Kickstart
The DS17x85/DS17x87 incorporates a wake-up feature
that powers on the system at a predetermined date and
time through activation of the PWR output pin. In addi-
tion, the kickstart feature allows the system to be pow-
ered up in response to a low-going transition on the KS
pin, without operating voltage applied to the VCC pin.
As a result, system power can be applied upon such
events as a key closure or modem ring-detect signal.
To use either the wake-up or the kickstart functions, the
DS17x85/DS17x87 must have an auxiliary battery con-
nected to the VBAUX pin, the oscillator must be running,
and the countdown chain must not be in reset (Register
A DV2, DV1, DV0 = 01X). If DV2 and DV1 are not in this
required state, the PWR pin is not driven low in
response to a kickstart or wake-up condition while in
battery-backed mode.
The wake-up feature is controlled through the wake-up
interrupt-enable bit in Extended Control Register 4B (WIE,
bank 1, 04BH). Setting WIE to 1 enables the wake-up fea-
ture, clearing WIE to 0 disables it. Similarly, the kickstart
interrupt-enable bit in Extended Control Register 4B
(KSE, bank 1, 04BH) controls the kickstart feature.
A wake-up sequence occurs as follows: When wake-up
is enabled through WIE = 1 while the system is pow-
ered down (no VCC voltage), the clock/calendar moni-
tors the current date for a match condition with the date
alarm register (bank 1, register 049H). With the date
alarm register, the hours, minutes, and seconds alarm
bytes in the clock/calendar register map (bank 0, regis-
ters 05H, 03H, and 01H) are also monitored. As a
result, a wake-up occurs at the date and time specified
by the date, hours, minutes, and seconds alarm regis-
ter values. This additional alarm occurs regardless of
the programming of the AIE bit (bank 0, register B,
0BH). When the match condition occurs, the PWR pin is
automatically driven low. This output can be used to
turn on the main system power supply that provides
VCC voltage to the DS17x85/DS17x87 as well as the
other major components in the system. Also at this
time, the wake-up flag (WF, bank 1, register 04AH) is
set, indicating that a wake-up condition has occurred.
A kickstart sequence occurs when kickstarting is
enabled through KSE = 1. While the system is powered
down, the KS input pin is monitored for a low-going
transition of minimum pulse width tKSPW. When such a
transition is detected, the PWR line is pulled low, as it is
for a wake-up condition. Also at this time, the kickstart
flag (KF, bank 1, register 04AH) is set, indicating that a
kickstart condition has occurred.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS17285S-5 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| DS17285S-5/T&R | 制造商:Maxim Integrated Products 功能描述:IC RTC 5V 2K NV RAM 24-SOIC |
| DS17285S-5/T&R | 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS17285S-5+ | 功能描述:实时时钟 3V/5V RTC K Multiplexed Kick-S RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS17285S-5+T&R | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 2KBYTE 24SOIC - Tape and Reel 制造商:Maxim Integrated Products 功能描述:Maxim Integrated DS17285S-5+T&R Real Time Clocks (RTC) 制造商:Maxim Integrated Products 功能描述:IC RTC 5V 2K NV RAM 24-SOIC |
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