参数资料
型号: DS1557WP-120
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: Timer or RTC
英文描述: 0 TIMER(S), REAL TIME CLOCK, DMA34
封装: POWERCAP MODULE-34
文件页数: 17/19页
文件大小: 331K
代理商: DS1557WP-120
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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相关代理商/技术参数
参数描述
DS1557WP-120+ 功能描述:实时时钟 4M NV RAM Timekeeper 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
DS1557WP-120IND 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
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