M48T212V-70MH1 STMICROELECTRONICS [STMicroelectronics], M48T212V-70MH1 Datasheet - Page 16

• Manufacturer Part Number: M48T212V-70MH1
• Description: 5V/3.3V TIMEKEEPER CONTROLLER Supervisor
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M48T212Y, M48T212V
Setting the Alarm Clock
Address locations 6h-2h contain the alarm set-
tings. 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. It can also be pro-
grammed to go off while the M48T212Y/V is in the
battery back-up to serve as a system wake-up call.
Bits RPT5-RPT1 put the alarm in the repeat mode
of operation. Table
rations. Codes not listed in the table default to the
once per second mode to quickly alert the user of
an incorrect alarm setting.
Note: User must transition address (or toggle chip
enable) to see Flag Bit change.
When the clock information matches the alarm
clock settings based on the match criteria defined
by RPT5-RPT1, the AF (Alarm Flag) is set.
Figure 8. Alarm Interrupt Reset Waveforms
Table 8. Alarm Repeat Modes
16/32
RPT5
1
1
1
1
1
0
A0-A3
ACTIVE FLAG BIT
IRQ/FT
RPT4
1
1
1
1
0
0
8
shows the possible configu-
RPT3
1h
1
1
1
0
0
0
RPT2
1
1
0
0
0
0
ADDRESS 0h
If AFE (Alarm Flag Enable) is also set, the alarm
condition activates the IRQ/FT pin. To disable
alarm, write '0' to the Alarm Date registers and
RPT1-5. The IRQ/FT output is cleared by a READ
to the Flags Register as shown in Figure 8. A sub-
sequent READ of the Flags Register is necessary
to see that the value of the Alarm Flag has been
reset to '0.'
The IRQ/FT pin can also be activated in the bat-
tery back-up mode. The IRQ/FT will go low if an
alarm occurs and both ABE (Alarm in Battery
Back-up Mode Enable) and AFE are set. The ABE
and AFE Bits are reset during power-up, therefore
an alarm generated during power-up will only set
AF. The user can read the Flag Register at system
boot-up to determine if an alarm was generated
while the M48T212Y/V was in the deselect mode
during power-up.
back-up mode alarm timing.
RPT1
1
0
0
0
0
0
Figure 9., page 17
HIGH-Z
Once per Second
Once per Minute
Once per Month
Alarm Setting
Once per Hour
Fh
Once per Year
Once per Day
AI03021
illustrates the