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参数资料
| 型号： | DS17885N-3 |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | XO, clock |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| 封装： | DIP-24 |
| 文件页数： | 10/38页 |
| 文件大小： | 410K |
| 代理商： | DS17885N-3 |
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DS17885/DS17887
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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.
The timing associated with both the wake-up and kickstarting sequences is illustrated in the
Wake-Up/Kickstart Timing Diagram in the Electrical Specifications section of this data sheet. The timing
associated with these functions is divided into five intervals, labeled 1 to 5 on the diagram.
The occurrence of either a kickstart or wake-up condition causes the PWR pin to be driven low, as
described above. During interval 1, if the supply voltage on the DS17885/DS17887 VCC pin rises above
the greater of VBAT or VPF before the power-on timeout period (tPOTO) expires, then PWR remains at the
active low level. If VCC does not rise above the greater of VBAT or VPF 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 WF or KF) associated with the attempted power-on sequence remains set
until cleared by software during a subsequent system power-on.
If VCC is applied within the timeout period, then the system power-on sequence continue as shown in
intervals 2 to 5 in the timing diagram. During interval 2, PWR remains active and IRQ is driven to its
active low level, indicating that either WF or KF was set in initiating the power-on. In the diagram KS is
assumed to be pulled up to the VBAUX supply. Also at this time, the PAB bit is automatically cleared to 0
in response to a successful power-on. The PWR line remains active as long as the PAB remains cleared to
0.
At the beginning of interval 3, the system processor has begun code execution and clears the interrupt
condition of WF and/or KF by writing 0’s to both of these control bits. As long as no other interrupt
within the DS17885/DS17887 is pending, the IRQ line is taken inactive once these bits are reset.
Execution of the application software can proceed. During this time, both the wake-up and kickstart
functions can be used to generate status and interrupts. WF is set in response to a date, hours, minutes,
and seconds match condition. KF is set in response to a low-going transition on KS . If the associated
interrupt-enable bit is set (WIE and/or KSE), then the IRQ line is driven active low in response to enabled
event. In addition, the other possible interrupt sources within the DS17885/DS17887 can cause IRQ to be
driven low. While system power is applied, the on-chip logic always attempts to drive the PWR pin active
in response to the enabled kickstart or wake-up condition. This is true even if PWR was previously
inactive as the result of power being applied by some means other than wake-up or kickstart.
The system can be powered down under software control by setting the PAB bit to a logic 1. This causes
the open-drain PWR pin to be placed in a high-impedance state, as shown at the beginning of interval 4 in
the timing diagram. As VCC voltage decays, the IRQ output pin is placed in a high-impedance state when
VCC goes below VPF. If the system is to be again powered on in response to a wake-up or kickstart, then
the both the WF and KF flags should be cleared and WIE and/or KSE should be enabled prior to setting
the PAB bit.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS17885N-5 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:3V/5V Real-Time Clock |
| DS17885S-3 | 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 |
| DS17885S-3+ | 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 |
| DS17885S-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 |
| DS17885S-5/T&R+ | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 8KBYTE 24SOIC - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC RTC 5V 8K NV RAM 24-SOIC |
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