Trying to understand octal buffers

[Diminuendo]

OK, so the way it has been explained to me, octal buffers are basically 8 switches that switch over automatically once one has been.

I'm trying to figure out how to activate them but I can't read circuit diagrams. I originally thought I was suppost to connect the two Output Enables to get it to work, but after reading it more I think it is the voltage, so here is my guess on how it's suppost to work written on the part sheet

so am I close?

Seriously any help would be great.

 

[Aux]

Buffers use an electrical proplerty called impedance (represented by Z) which, when in effect, resists change to the signal. In this chip the current goes from A to Y. Putting a HIGH signal (voltage) through OE turns impedance on between A and Y, so a change in the voltage to A won't immediately be seen in Y. In fact, small "hiccups" probably won't be seen at all- and that's presumably why you're using this chip. Putting OE to ground turns impedance off and directly connects A to Y, so changes will be seen immediately (buffering is turned off).

So in short... give OE voltage to buffer the signal from A to Y, and ground it if you just want straight-through operation.

 

[Diminuendo]

wow thanks that was really helpful

OK, so I'm just going to run through this with you so I'm clear though; If I connect OE to the ground I connect A to Y, but if I run voltage through OE it cuts/buffers the signal.

the way I'm applying this is that I'm using Ashens GC controller wiring guide to put a GC controller inside a SNES controller, and I want a switch to swap what the D-pad controls; the GC stick or Dpad.

 

[Aux]

Not exactly. Putting OE to ground will directly connect them, and basically act like the chip isn't there. Putting OE to voltage will enable buffering, not cut the signal. Let me try to explain how that works.

So you put a signal wire to 1A1 and you grab the output at 1Y1.

When OE is LO (ground), it just acts like the chip isn't there- whatever A is, Y will be also. If A starts out at say 12V and drops to 0V, Y will also drop at the same time.

When OE is HI (voltage), the impedance (resistance to change) is high and buffering will occur. If A starts out at 12V and drops to 0V, Y not change immediately but will slowly follow.

This is useful if your A is not stable but you want a stable-ish signal- since Y doesn't want to change, short drops in A's signal won't be reflected in the output at Y.

See how Y stays at more or less HI voltage, while A is kind of jumpy?

So that's when you want to use this chip, to stabilize a signal. Now, if I get what you're doing, you don't want to buffer, you want to actually switch some signals (the Dpad "up down left right" lines) between the chip's inputs for Dpad directional and the C-stick, right? I mean, the c-stick is analog I think so it's not going to be a direct translation, you may need to futz with your lines after the switch, but you're going to want a quad SPDT switch like this one (which is SMD, so not this one exactly maybe). You want a switch, not a buffer. Based on my understanding of what you want to do, at least.

 

[Diminuendo]

ok, Dang, so that's not going to work, thanks though.

A quad SPDT switch wouldn't cut it, it would have to be a hex, and I can't find either (quad or hex) anywhere online. My alternative is to baiscally get a whole bunch of DT switches, drill a hole in the plastic parts and put a metal bar in so they all switch together. basically, it's going to look like ass.

My misinterpretation came from this snippet of an episode of the BenHeck show. (don't worry, I trimmed the video so you don't have to watch the whole thing) So I'm wondering if he is straight out wrong, or if I have a kind of octal buffer that works how you say it does and he has a different kind.

 

[Aux]

Wow, yeah, I can see where that's confusing. And mostly wrong.

Why do you need a hex, isn't there 4 lines for the 4 directions? Also fun thing about switches, you can run the same selector lines to them and essentially run them in parallel- so two trips makes a hex. Or two doubles makes a quad. Or three doubles makes a hex. Something to think about.

 

[Diminuendo]

ok, that sucks, I think whatever Ben described would be an amazing modding tool, just going to put it out there and ask if anyone knows something similar to what I want.

I'm pretty sure the game cube sticks X and Y are actually grounds and the middle pin is a positive, someone is free to correct me if I'm wrongg

Also fun thing about switches, you can run the same selector lines to them and essentially run them in parallel- so two trips makes a hex. Or two doubles makes a quad. Or three doubles makes a hex. Something to think about.

I have no idea what any of that means, thanks for the suggestion though

 

[Diminuendo]

I think I just figured a way I can get these octal buffers to work the way I want:

What if I hard wired my ground to the OEs and set up a switch that connects and disconnects the GND and VCC pins? so the chip has no power at all?