What are the following additional options of reset and supervisor ICs used for?

TN0941

10/16

DocID023775 Rev 1

6.2

Battery freshness seal

A battery freshness seal avoids the discharge of leakage current from the battery it is

connected to. In practice, it disconnects the backup battery from the supply output voltage

and the internal circuitry until it is needed. This allows manufacturers to ensure that the

backup battery stays fresh when the final product is put to use.

Once a battery freshness seal is enabled (disconnecting the backup battery from the

More details

See AN1957: Microprocessor Supervisor Functions, page 20

Suggested products

For further information on battery freshness seals, please refer to the following products

STM817, STM818, and STM819.

6.3

Watchdog

A watchdog timer is used to protect the system against runaway software. If the system

software fails to occasionally reset the watchdog timer, the timer resets the microprocessor

thereby restoring the system to proper operation.

In a microcontroller, the embedded watchdog can be usually disabled by software, and its

timing is incremented with the microcontroller clock. Hence, it does not provide full

protection against hardware and software issues, which can be critical for applications

requiring stringent constraints for safety purpose.

Recommended use of standalone watchdogs

•

Applications requiring stringent constraints for safety purpose (medical applications,

alarms, security equipment).

•

Applications that need redundancy

•

Applications requiring a longer watchdog than the one provided by the microcontroller

More details

•

See AN1957: Microprocessor Supervisor Functions, page 11

•

See the STWD100 flyer: Standalone watchdog with chip enable improves system

reliability

Suggested products

For further information on watchdogs, please refer to the following products: STWD100,

STM6321, STM682x, STM69x, STM70x, STM80x, and STM81x.