Micro Crystal

Real Time Clock / Calendar Module

RV-8564

28/40

11.3.INTERFACE WATCHDOG TIMER

During read/write operations, the time counting circuits are frozen. To prevent a situation where the accessing

device becomes locked and does not clear the interface, the RV-8564 has a built in watchdog timer. Should the

interface be active for more than 1 s from the time a valid slave address is transmitted, then the RV-8564 will

automatically clear the interface and allow the time counting circuits to continue counting.

The watchdog is implemented to prevent the excessive loss of time due to interface access failure e. g. if main

power is removed from a battery backup system during an interface access.

Each time the watchdog period is exceeded, 1 s will be lost from the time counters. The watchdog will trigger

between 1 s and 2 s after receiving a valid slave address.

12.ABSOLUTE MAXIMUM RATING

PARAMETER

SYMBOL

CONDITIONS

MIN.

MAX.

UNIT

Supply voltage

-0.5

+6.5

V

Input voltage

Input Pin

V

Output voltage

INT Pin

V

Supply current

-50

+50

mA

DC Input current

-10

+10

mA

DC Output current

-10

+10

mA

Electrostatic discharge voltage

HBM

1)

-

+/-3500

V

MM

2)

-

+/-250

V

Latch-up current

All pins

3)

-

100

mA

Operating temperature range

-40

+85

°C

Storage temperature range

Stored as bare product

-55

+125

°C