atmega328p reset on power startup

Other Hardware 3rd Party Boards
1

Dear all,

could you please offer some explanation to my following question:

If I understand correctly, the reset pin on atmega328p has to be pulled low in order to reset the uC? On Arduino Uno, the atmega16U2 is responsible for resetting the atmega328p in order to upload new sketches right?

What about on power-up (plugging the Arduino to a power source)? The controller also resets? How is this performed?Does it have an internal reset?

I would like to have a standalone atmega328p on another board and program it via the Arduino Uno (using the Arduino bootloader). Once the chip is bootloaded, only Rx,Tx, RESET, VCC and GND are needed to do this.

My main question: If I program the atmega328p chip via Arduino Uno and then remove the Uno and unplug the atmega328p from power, what will happen, when I power the atmega328p back on as a standalone chip? Will it reset and start normally? If not, could you please explain what should I do to achieve this?

Thank you and best regards,
K

2

Power-up is a reset condition. Bringing reset low is another. There are other ways, like the watchdog timer.

3

Example, my GPS clock project:

http://arduino.cc/forum/index.php/topic,158296

That just resets when it powers on. There is no additional reset circuitry.

4

Have you considered programming the standalone chip via ICSP instead, using the ArduinoISP sketch on your Arduino?

5

Dear Mr. Gammon and dc42,

thank you for the help. I intend to use ICSP to program my chip via Arduino, but what I needed to know is that power-on is also a reset condition. I will also try to use watchdog timer as a reset method during the operation.

Thank you and best regards,
K