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參數(shù)資料
| 型號： | DS12887 |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Timer or RTC |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| 封裝： | DIP-24 |
| 文件頁數(shù)： | 14/19頁 |
| 文件大?。?/td> | 584K |
| 代理商： | DS12887 |
DS12887
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occurs on the AS bus will clear the address regardless of whether CS is asserted. Access commands
should be sent in pairs.
DS (Data Strobe or Read Input) – The DS/ RD pin has two modes of operation depending on the level
of the MOT pin. When the MOT pin is connected to VCC, Motorola bus timing is selected. In this mode
DS is a positive pulse during the latter portion of the bus cycle and is called Data Strobe. During read
cycles, DS signifies the time that the DS12887 is to drive the bidirectional bus. In write cycles the trailing
edge of DS causes the DS12887 to latch the written data. When the MOT pin is connected to GND, Intel
bus timing is selected. In this mode the DS pin is called Read ( RD ). RD identifies the time period when
the DS12887 drives the bus with read data. The RD signal is the same definition as the Output Enable
( OE ) signal on a typical memory.
R/ W (Read/Write Input) – The R/ W pin also has two modes of operation. When the MOT pin is
connected to VCC for Motorola timing, R/ W is at a level which indicates whether the current cycle is a
read or write. A read cycle is indicated with a high level on R/ W while DS is high. A write cycle is
indicated when R/ W is low during DS.
When the MOT pin is connected to GND for Intel timing, the R/ W signal is an active low signal called
WR. In this mode the R/ W pin has the same meaning as the Write Enable signal ( WE ) on generic RAMs.
CS
(Chip Select Input) – The Chip Select signal must be asserted low for a bus cycle in the DS12887 to
be accessed. CS must be kept in the active state during DS and AS for Motorola timing and during RD
and WR for Intel timing. Bus cycles which take place without asserting CS will latch addresses but no
access will occur. When VCC is below 4.25 volts, the DS12887 internally inhibits access cycles by
internally disabling the CS input. This action protects both the real time clock data and RAM data during
power outages.
IRQ
(Interrupt Request Output) – The IRQ pin is an active low output of the DS12887 that can be
used as an interrupt input to a processor. The IRQ output remains low as long as the status bit causing the
interrupt is present and the corresponding interrupt–enable bit is set. To clear the IRQ pin the processor
program normally reads the C register. The RESET pin also clears pending interrupts.
When no interrupt conditions are present, the IRQ level is in the high impedance state. Multiple
interrupting devices can be connected to an IRQ bus. The IRQ bus is an open drain output and requires an
external pullup resistor.
RESET
(Reset Input) – The RESET pin has no effect on the clock, calendar, or RAM. On power–up the
RESET
pin can be held low for a time in order to allow the power supply to stabilize. The amount of time
that RESET is held low is dependent on the application. However, if RESET is used on power–up, the
time RESET is low should exceed 200 ms to make sure that the internal timer that controls the DS12887
on power-up has timed out. When RESET is low and VCC is above 4.25 volts, the following occurs:
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1302S | 0 TIMER(S), REAL TIME CLOCK, PDSO8 |
| DS1302N | 0 TIMER(S), REAL TIME CLOCK, PDIP8 |
| DS1302SN | 0 TIMER(S), REAL TIME CLOCK, PDSO8 |
| DS1302 | 0 TIMER(S), REAL TIME CLOCK, PDIP8 |
| DS1302Z | 0 TIMER(S), REAL TIME CLOCK, PDSO8 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS12887+ | 功能描述:實時時鐘 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 |
| DS12887A | 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 |
| DS12887A+ | 功能描述:實時時鐘 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 |
| DS1290 | 功能描述:計數(shù)器移位寄存器 RoHS:否 制造商:Texas Instruments 計數(shù)器類型: 計數(shù)順序:Serial to Serial/Parallel 電路數(shù)量:1 封裝 / 箱體:SOIC-20 Wide 邏輯系列: 邏輯類型: 輸入線路數(shù)量:1 輸出類型:Open Drain 傳播延遲時間:650 ns 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝:Reel |
| DS12C887 | 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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