Wiring "Back' + 'Start' = Guide Button?


#1

Is it possible to wire the Back and Start buttons to act as the Guide button when pressed at the same time? I’ll be using a madcatz 360 PCB.

I’ve searched the FAQs to no avail.


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#2

You could do it, but you’d need to have a small PCB with a small microcontroller that has coded into it:

“If this pin and this pin are active at the same time, output to this pin”

and have the Guide button wired up to the “output to this pin” pin. Aside from that, I can’t think of any other way.


#3

Thanks for the info. I’ve purchased a TMO stick (pictured) and am limited to 2 extra function buttons. Maybe I’ll leave the “Back” button out, although some games use it for special options. Not sure what the best solution is. I’m sure not adding any holes in this case. NO WAY.

http://joystickvault.com/data/558/medium/MapleMini12.jpg


#4

Wire for the “Guide” button. You don’t really use the “Back” button in the types of games you would play with an arcade stick.


#5

I’m thinking though of tutorials/training modes where back might display a move list, etc.


#6

You could, sure, but that seems like massive overkill. The way I’d do it is with a (thinks about truth tables for a second…) OR gate. A single 50 cent OR gate chip like the 74-whatever-32, like this 74ACT32:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-4388-5-ND
Click the datasheet link to make sure you grok the pin numbering, but you’d want to wire it up like so:

+5v from the 360 pad (red wire of the USB cable) to pins 4, 5, 9, 10, 12, 13, 14
Ground to pin 7
The signal wire for back to pin 1
The signal wire for start to pin 2
The signal pad for guide on the pcb to pin 3
Pins 6, 8, and 11 are unused outputs, so you probably want to clip them off as close to the plastic as you can to keep them from touching anything.

Wired up this way, when both start and back are pressed, then start, back, and guide are all pressed.


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#7

Thanks toodles!


#8

With it wired up like that you’d be activating the guide button every time you hit start or back. Use an AND gate to get the desired results. If for some reason the simultaneous input of those 3 signals causes some unwanted effect (such as navigating somewhere else on the dashboard the instant that it comes up) then pick an inverter (a NOT gate) and wire a similar set up in the next 2 sets of 3 pins like you did with the first set, but having the inputs be the signal wire for back and start buttons be the first input of their respective set. Then have a signal wire from the guide button logic setup go to the inverter gate and then have that output sent as the 2nd input in both of the 3 pin sets. And finally send the outputs of those 2 logic sets sent to their respective signal pads. This extra wiring may not be necessary, but since I don’t have a 360, I don’t know how it responds when you hit guide, start, and back at the same time. Test it first to see what happens, and if nothing more than the dashboard popping up occurs, then you can save yourself the time and just use the first set of pins on the AND gate by themselves.


#9

god damn i read that and now i have no idea whats going on…


#10

ViperXL’s basically talking programming. In programming lingo, OR commands mean that “This or that” can occur and it’ll produce some effect. An AND command means that “This and that” must occur to produce an effect. He’s also mentions more in-depth wiring with things like a NOT gate (“This and that must occur, but NOT this”) but that’s a different matter.

ViperXL’s right though, you should figure out what Back+Start and Back+Start+Guide do before wiring up Back+Start = Guide. I recommend you do something like I have for my Sega Saturn to PSX converter code where you have Start+[Insert non-Back button here] be Guide so that you don’t accidentally “soft-reset” or anything.


#11

You know the more we discuss this, the less I care about the back button. Thanks everyone for the responses. I may just try this…


#12

sigh

Work with me here guys.
An AND gate has the output High if and only if BOTH inputs are High, and is Low for any other combination. We agree on that, right?
An OR gate has the out Low if and only if BOTH input are Low, and is High for any other combination. We agree on this as well, yes?

The 360 pad he’s using is a common ground pad, the same kind we always recommend whenever getting kinky with hacking. We agree on this? (Hope so, but using any kind of logic gate for anything else except maybe a common high is an excercise in frustration.)

When wiring up a common ground pad, the wire that runs to every switch ( the ‘common’) is connected to ground, thus, ‘common ground’. We agree on this, yes?

When a button or direction is pressed, the two wires connected to that switch are connected together. We agree on this as well?

So when a button or direction is pressed, the signal line for that button direction gets connected to ground. Still on track?

Ground is by definition 0 volts. In digital logic, that is a ‘Low’. Agreed?

Ergo, the signal line is Low when pressed, and it only makes sense that the signal line is High when not pressed.

We want the Guide button to activate at a certain time. To simulate this press, we want the voltage on the signal line to be Low at that certain time, and High the rest of the time when we don’t want it on, just like if we wired a button to it. Agreed?

We know when we want it to activate; when BOTH Back and Start are pressed. We already concluded that they are each Low when pressed, and High when not. We know we want the Guide signal line to be Low at that time, and High the rest of the time. So, let’s make a truth table:


 
Back  Start  Guide(output)
Low   Low  |  Low (This is the money shot; both are pressed, so make Guide pressed.)
High  Low   | High (Only one pressed, so keep Guide Unpressed)
Low   High  | High (Ditto)
High  High  | High (Nothing pressed, so keep Guide unpressed).

Or, in Binary:
0 0|0 
0 1|1
1 0|1
1 1|1
 

Thus, OR gate. If I’ve made a mistake somewhere in that line of reasoning, please point it up.

EDIT: As far as worries about it pressing Start+Back+Guide at the same time, that’s exactly how an xbox360 pad piggyback on a UPCB works, and it’s never been a problem in the year I’ve had mine done, and I’ve never had a complaint about it from the others who have piggybacked a 360 pad. The only caveat I can think of, if I’m remembering right, is that Back+Start soft resets SFAC, so if you bring up Guide when playing 3rd strike or (yuck) SF:AE, it may softreset to the game menu. For everything else, all of the normal stuff like waking up the xbox or turning it off, works peachy.


#13

i think toodles should just make a pcb for $9.99!


#14

Yes, you are correct toodles. I was looking at it from strictly the digital logic aspect, neglecting the fact that the low was in fact the desired output. I still stand by the additional wiring part (which would require a different wiring than the one I described earlier), however, since there are games that have soft resets, such as SFAE (which you mentioned). In addition, I have just noticed that in some applications on the PS3 (such as the web browser) pressing start and home at the same time will only allow the start input and the home input is ignored every time. Whether or not this occurs on the 360 is unknown to me.


#15

You could fix that problem by wiring the start or back signals to logic. Something like:

Back <- (Back)(Start)’

or equivocally

Back <- ((Back)’+(Start))’

The latter having the advantage of only requiring the additional purchase of a hex inverter. And since most online electronics retailers have a minimum order ANYWAY…


#16

We’d have to convert it through DeMorgan’s because it’s negative logic, so the formula you’d want is Back = Back + Start’; one OR gate and one NOT, but we’d have to interrupt the Back signal between the button and pad, which would mean we’d want a pullup resistor as well; Maybe not if a CMOS gate was used, but I never like going that way. If we’re okay with using a pullup resistor, I’d just say scrap the logic altogether and use a single 8 pin PIC like the 12F683 or one of less powerful equivalents. You can use an internal pull up resistor and do everything you need with a single 8 pin chip instead of multiple logic chips.

I still say the single OR chip is fine, but there is definitely no limit to the possibilities. If you can describe how you want it to behave, we can tell you how to do it.


#17

i say find someone to drill another hole lol


#18

That’s just crazy talk!


#19

If you have a clear acrylic bottom a ghetto temp solution would be to wire up the Home button to an external small bell-type switch and route the wire from underneath. Mabye leave one screw out so the clear plexi underneath will bend enough in a corner to let the 2 wires through.


#20

Hey BTW… i have a little questions… if i gonna use LB and RB from a Wireless Xbox 360 gamepad, y still have to neutralize the LT and RT??

Some one can show me where are the solder points for the sync button?.. thanks for now!