M4T28-BR12SH ST Microelectronics, M4T28-BR12SH Datasheet - Page 20

• Manufacturer Part Number: M4T28-BR12SH
• Description: TIMEKEEPER SNAPHAT Battery & Crystal
• Manufacturer: ST Microelectronics

M41ST85Y, M41ST85W
The IRQ/FT/OUT output is cleared by a READ to
the Flags Register. A 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 back-up mode. The IRQ/FT/OUT will go
low if an alarm occurs and both ABE (Alarm in Bat-
tery Back-up Mode Enable) and AFE are set. The
Figure 18. Alarm Interrupt Reset Waveform
Table 9. Alarm Repeat Modes
20/33
RPT5
1
1
1
1
1
0
ACTIVE FLAG
IRQ/FT/OUT
RPT4
0Eh
1
1
1
1
0
0
RPT3
1
1
1
0
0
0
0Fh
RPT2
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 M41ST85Y/W was in the de-
select mode during power-up. Figure 19, page 21
illustrates the back-up mode alarm timing.
1
1
0
0
0
0
RPT1
1
0
0
0
0
0
HIGH-Z
10h
Once per Second
Once per Minute
Once per Month
Alarm Setting
Once per Hour
Once per Year
Once per Day
AI03664