DS1553 Datasheet, PDF (9/20 Pages) Maxim Integrated Products – 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM

Figure 2. Clearing IRQ Waveforms
CE ,
DS1553 64kB, Nonvolatile, Year-2000-Compliant Timekeeping RAM
Figure 3. Clearing IRQ Waveforms
CE = Ø
The IRQ /FT pin can also be activated in the battery-backed mode. The IRQ /FT goes 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 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
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