DS1556_10 Datasheet, PDF (9/18 Pages) Maxim Integrated Products – 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM

Figure 3. Clearing IRQ Waveforms
DS1556 1M, Nonvolatile, Y2K-Compliant Timekeeping RAM
CE=0
The IRQ/FT pin can also be activated in the battery-backed mode. The IRQ/FT will go low if an alarm
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 will set 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
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