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What is Brownout timer?

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what is brown out timer

Hi there,

Will anyone please explain its uses and functioning? I’ve never used this one before!

Thanks
 

I think you are talking about brownout detector and watchdog timer.
 

Most of microcontroller systems operate with a Vdd power supply of nominally 5.0 volts, but they can operate on slightly higher and slightly lower voltages. What is of concern here is low voltages as might come about or in a system that occasionally has brief power failures. Sags in voltage are called brownouts., while a complete and sustained loss of power is called a blackout.
After restoring the power to Vdd>Vthreshold (usually somewhere about 4.2-4.5V) at any time, either suddenly or gradually, the brownout timer will reset the chip and the program will execute from the top with all variables zeroed.
 

Brownout reset is mostly employed in microcontrollers like pic (BOR) which triggers a interrupt when the Vcc supply volatage falls lower that safe working voltage, dur to momentry power supply fluctuations. the safe working volatage of micro is >4v this volatage is necessary to maintain the contents of RAM and proper execution of micro. if voltage drops below the safe level the RAM flipflips looses their charge and their contents becomes junk and values in instructuin pointer becomes corrupted and micro behaves abnoramlly. hence most of micro manufactures include this kind of reset to safely prevent micro going crazy and when the voltage returns to normal level micro start executing from the reset address.
 

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