The term "software reset" reffers to reset the arduino by internal codes. Generally there are three ways to reset arduino automatically:
1. use watchdog: an external hardware that activate the arduino reset function. The safest and most reliable way to do an automatic arduino reset.
2. use output pins with relay: when the pin is written to HIGH, it's attached relay connects the reset pin to Gnd, and that activates the reset function.
3. use software reset code: this only reset the running programm. This reset will command arduino to run the programm code from the beggining. (Bootloader, for example, will not be reset.)
It is useful to run automatic reset when using arduino for prototype of long-term usage.
Sofware reset can be done by some means:
1. void(* resetFunc) (void) = 0;
Declare this function in the code and when calling resetFunc(); the programm wil be reset.
2. void resetFunc() { asm volatile (" jmp 0"); }
This is the other way to declare the reset function.
Reference:
http://forum.arduino.cc/index.php?topic=49581.0
http://www.xappsoftware.com/wordpress/2013/06/24/three-ways-to-reset-an-arduino-board-by-code/
http://www.instructables.com/id/two-ways-to-reset-arduino-in-software/step2/using-just-software/
