SM8580AM

SEIKO NPC CORPORATION —21

INTERRUPT OPERATION

Alarm Interrupt

When AIE is 1 and an alarm event occurs (AF bit is set to 1), AIRQN output goes LOW. If AIE is 0, however,

AIRQN is in a high-impedance state. The alarm interrupt is output when a carry from the seconds register to

the minute register occurs.

Timer Interrupt

The timer interrupt mode (level interrupt or periodic interrupt) is selected by the setting of TI/TP.

Level interrupt mode (TI/TP = 0)

When TIE is 1 and a timer interrupt event occurs (TF bit is set to 1), TIRQN goes LOW. When TIE is 0, how-

ever, TIRQN is in a high-impedance state.

"1"

AIE bit

AIRQN pin

AF bit

"0"

Hi-Z

*No output while AIE bit is "0".

"1"

"0"

Interrupt is active.

"L" level

Setting AF bit to "0".

"1"

"1"

"0"

TIE bit

TIRQN pin

TF bit

"0"

"1"

Setting TF bit to "0".

Interrupt is active.

Hi-Z

"L" level

"0"

"1"

*No output while TIE bit is "0".

"1"

"1"

"0"