DS1553 Maxim, DS1553 Datasheet - Page 9

• Manufacturer Part Number: DS1553
• Description: The DS1553 is a full-function, year-2000-compliant (Y2KC) real-time clock/calendar (RTC) with an RTC alarm, watchdog timer, power-on reset, battery monitor, and "8k x 8 nonvolatile static RAM (NV SRAM)
• Manufacturer: Maxim

Figure 2. Clearing IRQ Waveforms
Figure 3. Clearing IRQ Waveforms
The
occurs and both ABE and AE are set. The ABE and AE bits are cleared during the power-up transition,
however, an alarm generated during power-up sets AF. Therefore, the AF bit can be read after system
power-up to determine if an alarm was generated during the power-up sequence. Figure 4 illustrates alarm
timing during the battery-backup mode and power-up states.
Figure 4. Backup Mode Alarm Waveforms
IRQ
CE
CE = Ø
,
/FT pin can also be activated in the battery-backed mode. The
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IRQ
/FT goes low if an alarm