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參數(shù)資料
| 型號： | DS1501WSN |
| 英文描述： | Y2K-Compliant Watchdog Real-Time Clocks |
| 中文描述： | 千年蟲的看門狗實時時鐘 |
| 文件頁數(shù)： | 17/20頁 |
| 文件大?。?/td> | 265K |
| 代理商： | DS1501WSN |
DS1501/DS1511 Y2K Watchdog Real-Time Clock
17 of 20
regardless of the state of the watchdog enable (WDE) bit, to serve as an indication to the processor that a
watchdog timeout has occurred. The watchdog timer operates in two modes, repetitive and single-shot.
If WDE is 1 and the watchdog steering bit (WDS) is 0, the watchdog is in repetitive mode. When the watchdog
times out, both WDF and IRQF are set.
IRQ
goes active and IRQF goes to 1. The watchdog timer is reloaded when
the processor performs a write of the watchdog registers and the timeout period restarts. Reading control A register
clears the
IRQ
flag.
If WDE and WDS are 1, the watchdog is in single-shot mode. When the watchdog times out,
RST
goes active for a
period of 40ms to 200ms. When
RST
goes inactive, WDE resets to 0. Writing a value of 00h to both watchdog
registers disables the watchdog timer. The watchdog function is automatically disabled upon power-up by the
power-on reset setting WDE = 0 and WDS = 0. The watchdog registers are not initialized at power-up and should
be initialized by the user.
Note:
The TE bit must be used to disable transfers when writing to the watchdog registers.
The following summarizes the configurations in which the watchdog can be used:
WDE = 0 and WDS = 0:
WDF is set.
WDE = 0 and WDS = 1:
WDF is set.
WDE = 1 and WDS = 0:
WDF and IRQF are set, and the
IRQ
pin is pulled low.
WDE = 1 and WDS = 1:
WDF is set, the
RST
pin pulses low, and WDE resets to 0.
WAKEUP/KICKSTART
The DS1501/DS1511 incorporate a wakeup feature, which powers on at a predetermined day/date and time by
activating the
PWR
output pin. Additionally, the kickstart feature allows 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
can be applied upon such events as key closure or a modem-ring-detect signal. To use either the wakeup or the
kickstart features, the DS1501DS1511 must have an auxiliary battery connected to the V
BAUX
pin, and the oscillator
must be running.
The wakeup feature is controlled through the time-of-day/date power-enable bit (TPE). Setting TPE to 1 enables
the wakeup feature. Transfers (TE) must be enabled for a wake up event to occur. Writing TPE to 0 disables the
wakeup feature. The kickstart feature is always enabled as long as V
BAUX
is present.
If the wakeup feature is enabled, while the system is powered down (no V
CC
voltage), the clock/calendar monitors
the current day or date for a match condition with day/date alarm register (0Bh). With the day/date alarm register,
the hours, minutes, and seconds alarm bytes in the clock/calendar register map (02h, 01h, and 00h) are also
monitored. As a result, a wakeup occurs at the day or date and time specified by the day/date, hours, minutes, and
seconds alarm register values. This additional alarm occurs regardless of the programming of the TIE bit. When the
match condition occurs, the
PWR
pin is automatically driven low. This output can turn on the main system power
supply that provides V
CC
voltage to the DS1501/DS1511, as well as the other major components in the system.
Also at this time, the time-of-day/date alarm flag is set (TDF), indicating a wakeup condition has occurred.
If V
BAUX
is present, while V
CC
is low, the
KS
input pin is monitored for a low-going transition of minimum pulse width
t
KSPW
. When such a transition is detected, the
PWR
line is pulled low, as it is for a wakeup condition. Also at this
time, KSF is set, indicating that a kickstart condition has occurred. The
KS
input pin is always enabled and must not
be allowed to float.
The timing associated with the wakeup and kickstarting sequences is illustrated in Figure 7. These functions are
divided into five intervals, labeled 1 to 5 on the diagram.
The occurrence of either a kickstart or wakeup condition causes the
PWR
pin to be driven low, as described above.
During Interval 1, if the supply voltage on the V
CC
pin rises above V
SO
before the power-on timeout period (t
POTO
)
expires, then
PWR
remains at the active-low level. If V
CC
does not rise above the V
SO
in this time, then the
PWR
output pin is turned off and returns to its high-impedance level. In this event, the
IRQ
pin also remains tri-stated.
The interrupt flag bit (either TDF or KSF) associated with the attempted power-on sequence remains set until
cleared by software during a subsequent system power-on.
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PDF描述 |
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| DS1611S | Power Supply Supervisor |
| DS1611SN | Power Supply Supervisor |
| DS1612 | Battery Management |
| DS1612E | Battery Management |
| DS1612EN | Battery Management |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1501WSN/T&R | 制造商:Maxim Integrated Products 功能描述:IC RTC WDOG Y2KC 3.3V IND 28SOIC |
| DS1501WSN/T&R | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1501WSN+ | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| DS1501WSN+T&R | 制造商:Maxim Integrated Products 功能描述:MAXIM DS1501WSN+T&R REAL TIME CLOCKS (RTC) - Tape and Reel 制造商:Maxim Integrated Products 功能描述:Maxim DS1501WSN+T&R Real Time Clocks (RTC) 制造商:Maxim Integrated Products 功能描述:IC RTC WDOG Y2K 3.3V IND 28SOIC |
| DS1501WSN+T&R | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
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