參數(shù)資料
型號: DS1557WP-120IND+
廠商: Maxim Integrated Products
文件頁數(shù): 17/17頁
文件大?。?/td> 0K
描述: IC RTC RAM Y2K 3.3V 120NS 34PCM
產(chǎn)品培訓(xùn)模塊: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標準包裝: 40
類型: 時鐘/日歷
特點: 警報器,閏年,NVSRAM,監(jiān)視計時器,Y2K
存儲容量: 512KB
時間格式: HH:MM:SS(24 小時)
數(shù)據(jù)格式: YY-MM-DD-dd
接口: 并聯(lián)
電源電壓: 2.97 V ~ 3.63 V
電壓 - 電源,電池: 3V
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 34-PowerCap? 模塊
供應(yīng)商設(shè)備封裝: 34-PowerCap 模塊
包裝: 管件
DS1557 4Meg, Nonvolatile, Y2K-Compliant Timekeeping RAM
9 of 17
USING THE WATCHDOG TIMER
The watchdog timer can be used to detect an out-of-control processor. The user programs the watchdog
timer by setting the desired amount of timeout into the 8-bit Watchdog Register (Address 7FFF7h). The
five Watchdog Register bits BMB4 to BMB0 store a binary multiplier and the two lower order bits RB1
to RB0 select the resolution, where 00=1/16 second, 01=1/4 second, 10=1 second, and 11=4 seconds. The
watchdog time-out value is then determined by the multiplication of the 5-bit multiplier value with the 2-
bit resolution value. (For example: writing 00001110 in the Watchdog Register = 3 X 1 second or
3 seconds.) If the processor does not reset the timer within the specified period, the Watchdog Flag (WF)
is set and a processor interrupt is generated and stays active until either the Watchdog Flag (WF) is read
or the Watchdog Register (7FFF7h) is read or written.
The most significant bit of the Watchdog Register is the Watchdog Steering Bit (WDS). When set to a 0,
the watchdog will activate the IRQ /FT output when the watchdog times out.
When WDS is set to a 1, the watchdog will output a negative pulse on the RST output for a duration of
40 ms to 200 ms. The Watchdog Register (7FFF7h) and the FT bit will reset to a 0 at the end of a
watchdog timeout when the WDS bit is set to a 1.
The watchdog timer resets when the processor performs a read or write of the Watchdog Register. The
timeout period then starts over. Writing a value of 00h to the Watchdog Register disables the watchdog
timer. The watchdog function is automatically disabled upon power-up and the Watchdog Register is
cleared. If the watchdog function is set to output to the
IRQ/FT output and the frequency test function is
activated, the watchdog function prevails and the frequency test function is denied.
POWER-ON DEFAULT STATES
Upon application of power to the device, the following register bits are set to a 0:
WDS = 0, BMB0 to BMB4 = 0, RB0 to RB1 = 0, AE = 0, ABE = 0.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1557WP-120IND+ 功能描述:實時時鐘 4M NV RAM Timekeeper 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
DS1557WP-150 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:4MEG NV Y2KC Timekeeping RAM
DS1558 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Watchdog Clock with NV RAM Control
DS1558B 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Watchdog Clock with NV RAM Control
DS1558D 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Watchdog Clock with NV RAM Control