參數(shù)資料
型號: DS1557P-70
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: Timer or RTC
英文描述: 0 TIMER(S), REAL TIME CLOCK, DMA34
封裝: POWERCAP MODULE-34
文件頁數(shù): 17/19頁
文件大小: 331K
代理商: DS1557P-70
DS1557 4Meg, Nonvolatile, Y2K-Compliant Timekeeping RAM
7 of 19
USING THE CLOCK ALARM
The alarm settings and control for the DS1557 reside within Registers 7FFF2h-7FFF5h. Register 7FFF6h
contains two alarm enable bits: Alarm Enable (AE) and Alarm in Backup Enable (ABE). The AE and
ABE bits must be set as described below for the
IRQ/FT output to be activated for a matched alarm
condition.
The alarm can be programmed to activate on a specific day of the month or repeat every day, hour,
minute, or second. It can also be programmed to go off while the DS1557 is in the battery-backed state of
operation to serve as a system wakeup. Alarm mask bits AM1 to AM4 control the alarm mode. Table 3
shows the possible settings. Configurations not listed in the table default to the once per second mode to
notify the user of an incorrect alarm setting.
Table 3. Alarm Mask Bits
AM4
AM3
AM2
AM1
ALARM RATE
1
Once per second
1
0
When seconds match
1
0
When minutes and seconds match
1
0
When hours, minutes, and seconds match
0
When date, hours, minutes, and seconds match
When the RTC Register values match Alarm Register settings, the Alarm Flag bit (AF) is set to a 1. If
Alarm Flag Enable (AE) is also set to a 1, the alarm condition activates the
IRQ/FT pin. The IRQ/FT
signal is cleared by a read or write to the Flags Register (Address 7FFF0h) as shown in Figure 2 and 3.
When
CE is active, the IRQ/FT signal may be cleared by having the address stable for as short as 15 ns
and either
OE or WE active, but is not guaranteed to be cleared unless t
RC is fulfilled. The alarm flag is
also cleared by a read or write to the Flags Register but the flag will not change states until the end of the
read/write cycle and the
IRQ/FT signal has been cleared.
Figure 2. Clearing
IRQ Waveforms
C
CE
E,,
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參數(shù)描述
DS1557P-70+ 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
DS1557P-70IND 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
DS1557P-70IND+ 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-120 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
DS1557WP-120+ 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