Arduino reset

I'm wondering how the reset on the Analog side of the board works.
(the one next to the 3.3v) Do you supply a voltage to it to make it reset? Haven't been able to find doc. on it. Could the Arduino be programmed to reset itself by sending a voltage to it?
Thanks

You must apply ground to that pin to make the Arduino reset.

Ok thanks. So I guess there isn't a way to program it to reset itself.

Well, you could connect a digital pin to the reset pin, couldn't you?
If the pin starts out connected to gnd, then just put some kind of not gate.
Wouldn't this work?

I think I heard somewhere that sometimes the arduino pins pulse momenarily on reset. Maybe use a couple transistors to make it so that one pin must be high, the other low, to reset?

I thought the atmel chips can't reset themselves this way?

I thought the atmel chips can't reset themselves this way?

You can't pulse the reset low by wiring it to a digital output pin. The AVR datasheet talks about it as being an incomplete reset cycle as the pin won't stay low long enough before the reset process turns all I/O pins to input mode.

The watch dog timer is the only reliable software way to reset the chip I believe, unless you are willing to utilize external components.

Normally there is seldom a legitimate reason for a sketch to require to reset it's self, it's just a matter of structuring the main loop function correctly. For the few times it is really needed, the WDT should be able to do the job.

Lefty

I think I heard somewhere that sometimes the arduino pins pulse momenarily on reset.

No they don't. They do go into an input mode on reset and if you are using a pin as an output it is briefly not driven. Maybe that is why some people mistakenly believe they are pulsed.

Thanks for the response. I really don't have a need to have it reset itself, as of now. I was just curious that if it took voltage to reset it then it could possibly be programmed to do so by pulsing an output to it.
I was mainly concerned about how it worked. Didn't want to stick a wire in there to find out.

Haven't been able to find doc. on it.

AFAIK every Arduino has an Open Source schematic. ie. Arduino-Diecimila-schematic.pdf

This might be too hard for folks to read, but this one basically says the Reset pin is pulled up to 5V with a 10K resistor, and the Reset button shorts the Reset pin to Ground when it's pressed.

The timing of Reset is a bit more complex, and you'd need to look at something like Atmels doc8161.pdf.

HTH
GB

There ARE chips ready made called "microprocessor supervisors". Among other things, they can handle a reset if told to. IE; Arduino make a brief trigger to the reset input of the chip... the chip take it from there.

If you are worried that the Arduino can't reset itself correctly... try one of these (or something similar): http://datasheets.maxim-ic.com/en/ds/DS1232.pdf