M41T82 datasheet(46/64 Pages) STMICROELECTRONICS

46 / 64 page

Clock operation

M41T82, M41T83

46/64

DocID012578 Rev 19

3.14.1

Active mode operation on VCC

On VCC, the operation of the output circuit is as shown in Table 14.

When OUT is 0 and FT is 0, the pin will be 0 regardless of whether any interrupts are

enabled.

When FT is a 1, the 512 Hz signal will be output if OUT is 0 or if no interrupts are enabled.

The interrupt sources control the pin when OUT is 1 and one or more of the interrupts are

enabled.

If OUT is 1, FT is 0 and no interrupts are enabled, then the pin will be 1.

Table 14. Priority for IRQ1/FT/OUT pin when operating on VCC

OUT(1)

FT(2)

A1IE(3)

+ OFIE(4)

+ TIE(5)

+ watchdog(6)

running

Comment

When OUT is 0 and FT is not enabled, OUT dominates

and none of the interrupt sources have any effect.

512 Hz

When FT = 1 and OUT = 1 and no interrupts are enabled,

the output will be the 512 Hz frequency test (FT) signal.

IRQ

When one or more interrupts are enabled, and OUT is a 1,

the pin stays high until one of the interrupts is asserted.

When OUT is 1, FT is 0 and no interrupts are enabled, the

pin is high.

OUT is bit 7 of register 08h (digital calibration).

FT is bit 6 of register 08h (digital calibration).

A1IE is bit 7 of register 0Ah (alarm 1, month).

OFIE is bit 7 of register 09h (watchdog).

TIE is bit 5 of register 11h (timer control).

The watchdog is controlled by register 09h (watchdog).

M41T82 Datasheet(PDF) 46 Page - STMicroelectronics