M48T201V-70MH1 STMICROELECTRONICS [STMicroelectronics], M48T201V-70MH1 Datasheet - Page 16

• Manufacturer Part Number: M48T201V-70MH1
• Description: 3.3V-5V TIMEKEEPER CONTROLLER
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M48T201Y, M48T201V
Setting the Alarm Clock
Registers 7FFF6h-7FFF2h contain the alarm set-
tings. The alarm can be configured to go off at a
prescribed time on a specific month, day of month,
hour, minute, or second or repeat every month,
day of month, hour, minute, or second.
It can also be programmed to go off while the
M48T201Y/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. If AFE
(Alarm Flag Enable) is also set, the alarm condi-
Figure 8. Alarm Interrupt Reset Waveforms
Table 6. Alarm Repeat Modes
16/33
RPT5
1
1
1
1
1
0
A0-A18
ACTIVE FLAG BIT
IRQ/FT
RPT4
1
1
1
1
0
0
6
shows the possible configu-
RPT3
1
1
1
0
0
0
RPT2
1
1
0
0
0
0
ADDRESS 7FFF0h
15ns Min
tion activates the IRQ/FT pin. To disable alarm,
write ’0’ to the Alarm-Date register and RPT1-5.
The IRQ/FT output is cleared by a READ to the
Flags Register as shown in Figure 8. A subse-
quent READ of the Flags Register is necessary to
see that the value of the Alarm Flag has been re-
set 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 M48T201Y/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
Once per Year
Once per Day
AI02331
illustrates the