M48T201Y, M48T201V

Clock operation

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If a battery low indication is generated during the 24-hour interval check, this indicates that

the battery is near end of life. However, data is not compromised due to the fact that a

Note:

This will cause the clock to lose time during the interval the battery/crystal is removed.

Thus applications which require extensive durations in the battery backup mode should be

powered-up periodically (at least once every few months) in order for this technique to be

beneficial. Additionally, if a battery low is indicated, data integrity should be verified upon

power-up via a checksum or other technique.

3.12

Initial power-on defaults

Upon application of power to the device, the following register bits are set to a '0' state:

WDS; BMB0-BMB4; RB0-RB1; AFE; ABE; SQWE; W; R; FT (see Table 9).

Table 9.

Default values

Condition

W

R

FT

AFE

ABE

SQWE

Watchdog

1.

WDS, BMB0-BMB4, RB0, RB1.

Initial power-up

(Battery attach for

2.

State of other control bits undefined.

000

000

0

3.

State of other control bits remains unchanged.

000

000

0

4.

Assuming these bits set to '1' prior to power-down.

000

111

0