Original Post

Hello, everyone.
I am designing development tool.
It is like ROM emulator.

I have question about that.
I want to know /RESET pin on the Virtual boy cartridge.
Many console cartridge have /RESET pin, so I think Virtual boy have it too.

Anyone know this? or does anyone have way to know?
I’ll be eagerly waiting for good answer.

I want to make the shooting game like the Space Harrier. πŸ™‚

11 Replies

Hello Jack!

INTERESTING! Could you give some more info about your projects? Maybe images?

Maybe this page can help you: <http://www.goliathindustries.com/vb/VBDiagrams.html>? I couldn’t find a reset pin on the diagrams though.

Please keep us updated on the tool and the game πŸ™‚

Hello, KR155E.
Thanks for your reply.

yes, of course I know that great web site, and I saw his VB programmers manual.pdf too.
but I cannot found information which I’m looking for.
Please give me a favor.

I promise to send it to you when I sorted out my information.

I am a natural born Japanese,
so I cannot speak English very well. I am sorry for my poor English.

Well, your english is OK, I understand everything πŸ™‚

I passed your question over in the chat, maybe someone can help you.

Hey Jack,

There is no /reset pin on the VB cart edge. I assume you’re looking for a pin to reset the system from the cart edge? If so, what you can do is use an interrupt, like pin 9, and have the ROM’s interrupt vector do the same as the reset vector, then the interrupt will reset the game.


…But that involves actually writing the interrupt into a ROM. I think he just wanted to know if its possible to reset the VB via a cart pin, which it isn’t (unless you count shorting VCC/GND :razz:).

Well… yeah, you have to write the interrupt to the ROM, but since he’s making a ROM emulator, that wouldn’t be much of a problem, since he’s got complete control over the ROM. It’d just be a simple copy/paste of 16 bytes to another location (and since an unmodified gccVB ROM has only the reset vector defined, grounding pin 9 will cause a reset).


Hi, DogP, lameboyadvance.

I want to reset via cart pin as said by lameboyadvance.
I am sorry, It was an insufficient explanation.

I want to control CPU reset via my computer’s parallel port.
Because if it can, I am unnecessary to turn off the power of the Virtual Boy whenever debugging.
This is very convenient for modify the code many times.

VB programmers manual says that pin 5 is possibly RESET.
I think this is what I want.
but I don’t have way to make sure.

Pull pin 5 high or low while the VB is running, that should let you know if it is a valid reset. As mentioned before it is trivial to make an interupt handler that waits for the expansion cart interupt. This way you can ‘break in’ anytime you want by pulling the cart interupt line. Not only would this let you do a reset, but you could also do memory/register dumps and you would be free to resume the games execution at will…

I just looked back at my notes on what pin 5 does, it’s connected to a pin on the PSRAM and CPU, and sometimes causes the system to lock up, so that won’t help you for a reset. There’s probably some other tricks you could do, but I’d vote for the interrupt.


Post Edited (05-06-05 07:37)

I would also vote for using the interrupt, but another way would be to actually control the VB’s power source (i.e. perform a “cold reboot.”)

This can be done one of two ways: (Without modifying the VB or keypad…)

1. Put a relay, power transistor, or other switch in series with the (6 to 15 VDC) power source going to or coming from the keypad.

2. (This will require testing) Connecting +5 VDC to one or more of the Vcc lines on the cart socket should power the rest of the VB, basically bypassing it’s voltage regulator. (Be sure you DO NOT put batteries or an adapter in the keypad, of course! ;-)) If so, you could then control this source as in option #1.

Of course, by modifying the VB, there are a number of ways it could be done. You could even change pin 5 into an actual /RESET line.


I second the call for interupt vectors. If your rom emulator has a little logic to controll the rom access to the interup vectors you can easily break in to any game at anytime, do a soft reset (very fast) and of cource break on any interupt without affecting the game play. This is trivial since the interupt vectors are on even byte boundarys and you know there addresses. Just build in an simple address decoder using logic gates if you want.

if you need more help we are all interested in seeing someone develop a better hardware developer for the VB. Just post your design and we will review it for you.

David Tucker


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