Datasheet

DocID012578 Rev 16 45/64
M41T82, M41T83 Clock operation
Figure 25. IRQ1/FT/OUT output pin circuit
The timer, oscillator fail detect circuit, alarm 1, and watchdog are ORed together as the
primary interrupt sources. The frequency test signal, FT, is used to enable a 512 Hz output
on the IRQ1/FT/OUT pin for calibrating the RTC. When not used as an interrupt or
frequency test output, the pin can be used as a discrete logic output controlled by the OUT
bit. The ABE bit is used to enable interrupts during backup mode.
Operating on V
CC
, all four interrupt sources are available. During backup, the timer and
watchdog are disabled, and the only interrupt sources are alarm 1 and the oscillator fail
detect circuit.
TIMER
TF
OFIE
AI1E
WDOG
OF
Q
PRE
reload
AF1
WDF
OUT
FT
A1IE
OFIE
TIE
w-dog running
ABE
IRQ1/OUT/FT
TE
Write OF to 0
to clear
Read FLAGS register
to clear
Write watchdog register
to clear
IRQ1/OUT/FT
LOGIC
TI/TP
TIE
AM03013v1