BQ4802YDWRG4 Datasheet, PDF (16/26 Pages) Texas Instruments – PARALLEL REAL-TIME CLOCK WITH CPU SUPERVISOR

bq4802Y
bq4802LY
SLUS464C – AUGUST 2000 – REVISED JUNE 2002
www.ti.com
Table 6. Alarm Frequency
1h
3h
5h
7h
ALM1–ALM0 ALM1–ALM0 ALM1–ALM0 ALM1–ALM0
ALARM FREQUENCY
1
1
1
1
Once per second
0
1
1
1
Once per minute when seconds match
0
0
1
1
Once per hour, when minutes and seconds match
0
0
0
1
Once per day, when hours, minutes and seconds match
0
0
0
0
When date, hours minutes and seconds match
POWER–FAIL INTERRUPT
When V_CC falls to the power-fail-detect point, the
power-fail flag PWRF is set. If the power-fail interrupt
enable bit (PWRIE) is also set, then INT is asserted low.
The power-fail interrupt occurs t_WPT before the
bq4802Y/bq4802LY generates a reset and deselects.
BATTERY–LOW WARNING
The bq4802Y/bq4802LY checks the battery on power-up.
When the battery voltage is approximately 2.1 V, the
battery valid flag BVF in the flags register is set to a 0
indicating that clock and RAM data may be invalid.
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