M41ST84WMQ6F STMicroelectronics, M41ST84WMQ6F Datasheet - Page 21

• Manufacturer Part Number: M41ST84WMQ6F
• Description: IC RTC 3V 512BIT NVRAM 16SOIC
• Manufacturer: STMicroelectronics
• Type: Clock/Calendar/Supervisorr

Specifications of M41ST84WMQ6F

• Memory Size: 64B
• Time Format: HH:MM:SS:hh (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-4693-2

M41ST84W
3.4
Note:
Setting alarm clock registers
Address 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. It can also be programmed to go off while the
M41ST84W is in the battery backup to serve as a system wakeup call.
Bits RPT5-RPT1 put the alarm in the repeat mode of operation.
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 RPT5-RPT1, the AF (alarm flag) is set. If AFE (alarm flag enable) is also set, the
alarm condition activates the IRQ/FT/OUT pin.
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 “alarm seconds,” the
address pointer will increment to the flag address, causing this situation to occur.
The IRQ/FT/OUT output is cleared by a READ to the flags register as shown in
subsequent READ of the flags register is necessary to see that the value of the alarm flag
has been reset to '0.'
The IRQ/FT/OUT pin can also be activated in the battery backup mode. The IRQ/FT/OUT
will go low if an alarm occurs and both ABE (alarm in battery backup 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 M41ST84W was in the deselect mode during
power-up.
Figure 14. Alarm interrupt reset waveform
Table 4.
ACTIVE FLAG
IRQ/FT/OUT
RPT5
1
1
1
1
1
0
Figure 15 on page 22
Alarm repeat modes
0Eh
RPT4
1
1
1
1
0
0
Doc ID 7530 Rev 9
RPT3
illustrates the backup mode alarm timing.
1
1
1
0
0
0
0Fh
RPT2
1
1
0
0
0
0
RPT1
1
0
0
0
0
0
Table 4
shows the possible
Once per second
Once per minute
Once per month
Alarm setting
Once per hour
Clock operation
Once per year
Once per day
HIGH-Z
10h
Figure
AI03664
14. A
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