AVR MCU reset: watchdog reset, power-on reset, power-off reset

I see that you are still not very clear about reset, especially the reset function inside the AVR microcontroller. I will briefly explain it here, hoping that you can have a general understanding at home. If there are any mistakes, I hope you can point them out. If you think they are good, please help me to give a thumbs up.

There are four types of AVR microcontroller resets: power-on reset, power-off reset, watchdog timeout reset, and external reset.

Power-on reset: It is to reset the microcontroller when the power is turned on. This is the same as the function of our external RC reset circuit. The AVR microcontroller has a power-on reset function inside.

Power-off reset: When the voltage suddenly drops during the operation of the MCU, the MCU will have many uncertain phenomena, so it is necessary to reset the MCU to put it in a certain state. This is the BOD function, a very practical function, and the AVR MCU has this function.

Watchdog reset: This is what we often call a watchdog. When the program enters a certain place and there is no response for a long time, the microcontroller will be reset. The AVR microcontroller has a watchdog function.

External reset: Needless to say, this is to forcibly reset the microcontroller through the reset pin.

Old RC reset circuit: The external RC reset circuit can achieve the power-on reset function under normal power-on conditions, but it is powerless against the other types of reset mentioned above.

The AVR microcontroller has a fully functional reset circuit integrated inside, which can completely replace the professional reset circuit, not to mention the external RC circuit.

Therefore, the microcontroller can be used with confidence as long as a pull-up resistor is connected to the reset pin and the internal watchdog and BOD functions are turned on.