DS1284/DS1286

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interrupt output goes to the active state, which is determined by bits 0, 4, 5, and 6 of the command

register.

Bit 1: Watchdog Alarm Flag (WAF). When this bit is set internally to logic 1, a watchdog alarm has

occurred. This bit is read-only and writing this register has no effect on the bit. The bit is reset when any

of the watchdog alarm registers are accessed. The WAM bit has no effect on the operation of this bit. If

pulse mode (PU/LVL = 1) is selected, the watchdog continues to run and the flag is internally written to 0

at the end of the pulse. The WAM bit has no effect on the operation of this bit.

Bit 0: Time-of-Day Alarm Flag (TDF). When this bit is set internally to a logic 1, indicates that a match

with the time-of-day alarm registers has occurred. This bit is read-only and writing this register has no

effect on the bit. The time of the alarm can be determined by reading the time-of-day alarm registers. The

bit is reset when any of the time-of-day alarm registers are read. The TDM bit has no effect on the

operation of this bit.

Figure 3. Time-of-Day Alarm Mask Bits

REGISTER

(03h)

MINUTES

(05h)

HOURS

(07h)

DAYS

FUNCTION

1

1

1

Alarm once per minute

0

1

1

Alarm when minutes match

0

0

1

Alarm when hours and minutes match

0

0

0

Alarm when hours, minutes, and days match