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參數(shù)資料
| 型號： | DS17887-5 |
| 英文描述： | Real-Time Clock |
| 中文描述： | 實(shí)時(shí)時(shí)鐘 |
| 文件頁數(shù)： | 17/38頁 |
| 文件大?。?/td> | 515K |
| 代理商： | DS17887-5 |
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DS17885/DS17887
17 of 38
AUXILIARY BATTERY
The V
BAUX
input is provided to supply power from an auxiliary battery for the DS17885/DS17887
kickstart, wake-up, and SQW output features in the absence of V
CC
. This power source must be available
in order to use these auxiliary features when no V
CC
is applied to the device.
The Auxiliary Battery Enable (ABE; bank 1, register 04BH) bit in extended control register B is used to
turn on and off the auxiliary battery for the above functions in the absence of V
CC
. When set to a 1,
V
BAUX
battery power is enabled, and when cleared to 0, V
BAUX
battery power is disabled to these
functions.
In the DS17885/DS17887, this auxiliary battery may be used as the primary backup power source for
maintaining the clock/calendar, user RAM, and extended external RAM functions. This occurs if the
V
BAT
pin is at a lower voltage than V
BAUX
. If the DS17885 is to be backed-up using a single battery with
the auxiliary features enabled, then V
BAUX
should be used and V
BAT
should be grounded. If V
BAUX
is not
to be used, it should be grounded and ABE should be cleared to 0.
WAKE-UP/KICKSTART
The DS17885/DS17887 incorporates a wake-up feature which can power the system on at a
predetermined date and time through activation of the
PWR
output pin. In addition, the kickstart feature
can allow the system to be powered up in response to a low going transition on the
KS
pin, without
operating voltage applied to the V
CC
pin. As a result, system power may be applied upon such events as a
key closure, or modem ring detect signal. In order to use either the wake-up or the kickstart features, the
DS17885/DS17887 must have an auxiliary battery connected to the V
BAUX
pin and the oscillator must be
running and the countdown chain must not be in reset (Register A DV2, DV1, DV0 = 01X). If DV2,
DV1, and DV0 are not in this required state, the
PWR
pin will not be 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 B
(WIE, bank 1, 04BH). Setting WIE to 1 enables the wake-up feature, clearing WIE to 0 disables it.
Similarly, the kickstart feature is controlled through the Kickstart Interrupt Enable bit in extended control
register B (KSE, bank 1, 04BH).
A wake-up sequence will occur as follows: When wake-up is enabled via WIE = 1 while the system is
powered down (no V
CC
voltage), the clock/calendar will monitor the current date for a match condition
with the date alarm register (bank 1, register 049H). In conjunction with the date alarm register, the
hours, minutes, and seconds alarm bytes in the clock/calendar register map (bank 0, registers 05H, 03H,
and 01H) are also monitored. As a result, a wake-up will occur at the date and time specified by the date,
hours, minutes, and seconds alarm register values. This additional alarm will occur regardless of the
programming of the AIE bit (bank 0, register B, 0BH). When the match condition occurs, the
PWR
pin
will automatically be driven low. This output can be used to turn on the main system power supply
which provides V
CC
voltage to the DS17885/DS17887 as well as the other major components in the
system. Also at this time, the Wake-Up flag (WF, bank 1, register 04AH) will be set, indicating that a
wake-up condition has occurred.
A kickstart sequence will occur when kickstarting is enabled via KSE = 1. While the system is powered
down, the
KS
input pin will be monitored for a low going transition of minimum pulse width t
KSPW
.
When such a transition is detected, the
PWR
line will be pulled low, as it is for a wake-up condition.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS17887-5 IND | 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS17887-5+ | 功能描述:實(shí)時(shí)時(shí)鐘 3V/5V RTC RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS17887-5IND | 功能描述:IC RTC 5V 8K NV RAM 24-EDIP RoHS:否 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 實(shí)時(shí)時(shí)鐘 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 類型:時(shí)鐘/日歷 特點(diǎn):警報(bào)器，閏年，SRAM 存儲(chǔ)容量:- 時(shí)間格式:HH:MM:SS（12/24 小時(shí)） 數(shù)據(jù)格式:YY-MM-DD-dd 接口:SPI 電源電壓:2 V ~ 5.5 V 電壓 - 電源，電池:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-WDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-TDFN EP 包裝:管件 |
| DS17887-5IND+ | 功能描述:實(shí)時(shí)時(shí)鐘 3V/5V RTC RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS17H531D | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:3-PHASE STEPPING SYSTEMS |
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