RV-4162 Datasheet, PDF (21/39 Pages) MICORO CRYSTAL SWITZERLAND – Ultra Small Real Time Clock

Micro Crystal
Ultra Small Real Time Clock / Calendar Module
RV-4162
4.4. ALARM FUNCTION
Addresses locations 0Ah-0Eh contain the alarm settings. The alarm can be configured to go off at a prescribed
time on a specific month, date, hour, minute, or second, or repeat every year, month, day, hour, minute, or second.
Bits ARM5 - ARM1 put the alarm in the repeat mode of operation. The table below shows the possible
configurations. Codes not listed in the table default to the once per second mode to quickly alert the user of an
incorrect alarm setting.
When the clock information matches the alarm clock settings based on the match criteria defined by ARM5 -
ARM1, the AF (alarm flag) is set. If AFE (alarm flag enable) is also set, the alarm condition activates the INT pin 6.
To disable the alarm, write “0” to the Date Alarm register and to ARM5 - ARM1.
Note: If the address pointer is allowed to increment to the flag register address, an alarm condition will not cause
the interrupt / flag to occur until the address pointer is moved to a different address. It should also be noted that if
the last address written is the Second Alarm, the address pointer will increment to the flag address, causing this
situation to occur.
The INT is cleared by a READ to the Flags register as shown in figure below. A subsequent READ of the Flags
register is necessary to see that the value of the alarm flag has been reset to “0”.
Alarm interrupt reset waveform:
INT
Alarm Repeat Mode Settings (addresses 0Bh to 0Eh, ARM5 to ARM1…bits description)
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2
0Bh
Date Alarm
0Ch
Hour Alarm
0Dh
Minute Alarm
0Eh
Second Alarm
ARM4 ARM5
20
10
8
4
ARM3
0
20
10
8
4
ARM2
40
20
10
8
4
ARM1
40
20
10
8
4
ARM5
1
1
1
1
1
0
ARM4
1
1
1
1
0
0
ARM3
1
1
1
0
0
0
ARM2
1
1
0
0
0
0
ARM1
1
0
0
0
0
0
Once per second
Once per minute
Once per hour
Once per day
Once per month
Once per year
Alarm setting
Bit 1
2
2
2
2
Bit 0
1
1
1
1
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