[Q] How to Reset the NES from the Cartridge Connector

[elseyf]

As the title suggests, I would like to know how I can reset the NES without the need to hit the RESET Button. I could only find out that the SNES has a RESET Line on the connector which is possibly used to reset the console with a signal from a Cartridge.
I think in the MultiCart projects of the member FARID, there is a method used with the M2 Line of the Cartridge Connector in order to reset the console with a signal without needing to Push reset and have the correct game selected, but I have no idea of what is actually happening to the M2 (is a certain voltage applied to it or is it pulled into a LOW state or what?).

I hope somene can clarify this or tell me a method on how this is done.

The only method I can think of is going the risky way and shorting the Vcc and GND lines of the Cartridge connector, but I can imagine this causing damage to the Hardware of the NES.

[lidnariq]

There is no way to request a reset from the cartridge connector.
Do not short out Vcc and Gnd, because that will, one day in the future, cause the capacitor and/or voltage regulator to blow up.

However, you can manually jump to the reset vector, and (if necessary and possible) reset the mapper into the correct state for reset.

The circuit FARID used is the same one I outlined here, and it detects reset.

[elseyf]

Naaah, too bad there is no Reset Option triggerable from the Cart Connector... I had a funny project in mind, which would have used at least the Soft-Reset (pressing the Reset button) through Cartridge Connector for simplifying the program which i would have used.

Now to the "going manually to the reset vector", what does it do in detail? Just reset the mapper chip or what? Or is it possible to reset the whole console by accessing the reset vector? It would be good if you could clarify it because I can only find that the reset vector is somewhat the beginnig of the whole program (game) which is executed in the beginning and after a console reset it is also accessed to restart the program (as far as i understood)

[tepples]

Now to the "going manually to the reset vector", what does it do in detail?

It means JMP ($FFFC). For mappers that don't watch M2, that's essentially the same from the game's point of view as actually pushing the Reset button of a top-loading console (Famicom or NES-101).

[tokumaru]

The reset vector points to the beginning of the program. When you turn on (or reset) the console, the CPU automatically jumps to the address indicated by this vector. If you manually jump to it, the program starts executing from the beginning again, which is practically the same as resetting the console. All games I'm aware of initialize everything, including the mapper, before showing anything to the player, so JMP ($FFFC) should always behave like a soft reset. Multicarts and Flash carts that watch what's happening electrically are the exception though... For example, if a game is running on the PowerPak and it JMPs to ($FFFC) the game will reset, you'll not go back to the PowerPak menu.