DocID023775 Rev 1

7/16

TN0941

What are the following core features of reset and supervisor ICs used for?

16

5.3

Manual reset (MR)

Some supervisor devices include a manual reset input (MR) that can be used by the user, or

the external device, to generate a reset. Typically, a low cost push-button switch is

connected to the MR input, which allows the user to restart the processor without turning off

the power. No additional components are needed because supervisor devices already

include a debounce IP that filters the noise of contact closure. This function can be used to

debug, to perform the final test of a processor, or to restart a processor that is locked. The

reset button is also useful in systems where the processor is never turned off, even when

the system is in off mode. Some processors include an internal reset that operates correctly

under stable power supply conditions, but usually has difficulties in handling voltage drops

therefore recommended.

More details

•

See AN1957: Microprocessor Supervisor Functions, page 13

•

See AN1772: How to Control Power-up/Reset and Monitor the Voltage in

Microprocessor Systems using ST Reset Circuits

5.4

guarantees that all connected devices are properly reset and that the system restarts

synchronously. Typical values are 150 ms or 210 ms, but the ST portfolio offers

configurations from 1.4 ms to 1680 ms and even an adjustable configuration.

Suggested products

•

•

•