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USB "Gamepad" encoder questions

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tetsujin:


--- Quote from: krick on January 27, 2005, 08:46:12 pm ---Ultimately, at the BIOS level, they all need to get the attention of the CPU for data transfers by using the IRQ system.  Now with that in mind, consider the fact that the motherboard keyboard controller uses IRQ#1, the second highest priority IRQ and this is a dedicated IRQ that is NEVER shared with any other device.
--- End quote ---

I read about that in another thread here, but I don't know how significant it really is that the keyboard IRQ has higher priority than the other device IRQs.  The priority only comes into play (I believe) when multiple requests are received simultaneously.  But more to the point, I have a real hard time believing this makes any practical difference.  Because of the nature of USB and the keyboard port we're already talking about latencies on the order of milliseconds.  The interrupt system's latency on a 1Ghz+ processor is probably in the microseconds.  I guess If my USB controller were on IRQ 10 or 11, and some interrupty device on IRQ 9 took a hell of a lot of the CPU's attention, then maybe it would have a measurable impact...  The only other higher-priority IRQs would be 8 (real-time clock, used to set alarms and such) and IRQ 0 and IRQ 1.

Though if anybody more educated than myself on the subject of modern PC internals would like to speak, I'll listen and take notes.

NoOne=NBA=:


--- Quote from: tetsujin on January 27, 2005, 08:33:35 pm ---Nevertheless, I am not at all interested in this debate about why you think I should use a keyboard encoder.
--- End quote ---
That was NEVER the debate here.
I was trying to find out if you had any relevant information on the keyboard vs. gamepad front, that the rest of us should know.
It was never about what YOU should do, but rather about what the REST of us should do.


--- Quote ---I'm a bit of a tech-head and a tech-purist and I want my joysticks to be encoded as joysticks. That's pretty much it.
--- End quote ---
Most of us here are tech-heads, and are always searching for more knowledge about things that interest us.
That's why we were pumping you for information about why you wanted gamepads.
Now we know WHY.
There is no technical reason for it, you just "want to".
THAT is what we were trying to find out.
We don't really care what you hook up, that is your business.
What we want to know is if there was a reason that WE shouldn't be using keyboard encoders.


--- Quote ---I think it's awesome that I can buy a $20 controller that's decked out like a PSX controller, rig up hubs and plug in 50 of the buggers if I want.
--- End quote ---
So are you still planning to make custom encoders, and use arcade controls; or are you just going to plug in a bunch of iShocks, and use them as-is now?


--- Quote ---The one emulator that comes to mind that I did have serious problems with USB gamepads is MacMAME.
--- End quote ---


tetsujin:


--- Quote from: NoOne=NBA= on January 28, 2005, 02:39:55 am ---
--- Quote from: tetsujin on January 27, 2005, 08:33:35 pm ---Nevertheless, I am not at all interested in this debate about why you think I should use a keyboard encoder.
--- End quote ---
That was NEVER the debate here.


--- Quote ---The situation I'm trying to avoid is one where I build the controls and set up the software, and play a bunch of games, and then a few months down the road I or someone else plays a game and realizes, "hey, this is a little laggy, isn't it?"  Or what if it's a problem I'll only see once I've got a four-player console going?  Not something I can easily test on my own.
--- End quote ---
Why not go for the PROVEN method then, and use a PS/2 keyboard encoder for P-1/P-2, and external USB gamepads for P-3/P-4?

--- End quote ---

Dude, seriously.  I've explained my feelings on this issue.  Enough.

NoOne=NBA=:

DUDE, this STILL isn't about YOU.
That's the part I'm trying to get you to grasp.
This is about the next guy that comes BEHIND you, wanting to know the same thing.

I offered that solution because it is PROVEN, and you are worried about putting something together that you KNOW will work from the start.
That WILL work for you.

Knowing that, if you want to go put something together that MIGHT work, go for it.
That's what most of us here do anyway.
We buy stuff, we hook it up, we report back to the next guy here, so that HE doesn't have to buy the SAME stuff, and try it himself.
The next guy coming along wanting to know about gamepads may be of a more conservative bent, and want to play it safe.
This information is for HIM.

crashwg:

Or her!  :P

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