M48T201V-85MH1TR View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

M48T201V-85MH1TR

5.0 or 3.3 V TIMEKEEPER® supervisor

STMicroelectronics 

M48T201Y, M48T201V

Clock operation

Note:

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

nominal VCC is supplied. In order to insure data integrity during subsequent periods of

battery backup mode, the battery should be replaced. The SNAPHAT® top may be replaced

while VCC is applied to the device.

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

The M48T201Y/V only monitors the battery when a nominal VCC is applied to the device.

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

Initial power-up

(Battery attach for

SNAPHAT)(2)

RESET(3)

Power-down(4)

0

0

0

0

0

0

0

0

0

1. WDS, BMB0-BMB4, RB0, RB1.

2. State of other control bits undefined.

3. State of other control bits remains unchanged.

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

AFE

ABE

SQWE

Watchdog

register(1)

0

0

0

0

0

0

0

0

1

1

1

0

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