参数资料
型号: DS1685S-5
厂商: DALLAS SEMICONDUCTOR
元件分类: Timer or RTC
英文描述: 1 TIMER(S), REAL TIME CLOCK, PDSO24
封装: SOIC-24
文件页数: 9/39页
文件大小: 290K
代理商: DS1685S-5
DS1685/DS1687
17 of 39
AUXILIARY BATTERY
The VBAUX input is provided to supply power from an auxiliary battery for the DS1685/DS1687 kickstart,
wake-up, and SQW output features in the absence of VCC. This power source must be available in order
to use these auxiliary features when no VCC 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 VCC. When set to a 1,
VBAUX battery power is enabled, and when cleared to 0, VBAUX battery power is disabled to these
functions.
In the DS1685/DS1687, 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
VBAT pin is at a lower voltage than VBAUX. If the DS1685 is to be backed-up using a single battery with
the auxiliary features 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 DS1685/DS1687 incorporates a wake-up feature which can power the system on at a pre-determined
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 VCC 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
DS1685/DS1687 must have an auxiliary battery connected to the VBAUX 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 kick-start 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 VCC 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 VCC voltage to the DS1685/DS1687 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.
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相关代理商/技术参数
参数描述
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DS1685S-5/TR 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:3V/5V Real-Time Clocks
DS1685S-5_12 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:3V/5V Real-Time Clocks
DS1685S-5+ 功能描述:实时时钟 3V/5V RTC 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
DS1685S-5+T& 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:3V/5V Real-Time Clocks