How do I change the clock speed of a PSX CONTROLLER?

nonzero · Post by **nonzero** » Mon May 21, 2007 11:50 am

Working on a project at the min that a PSX/2 controller would be perfect for, only problem is that the info I've dug up says that it's rate is nominally 250 Kbaud.

Crazy high, I need to drop that to something sensible for the interface, 4800 baud would be nice

Any ideas?

Thanks

Post by **gannon** » Mon May 21, 2007 11:57 am

I thought the speed was dependent on the input clock?

nonzero · Post by **nonzero** » Mon May 21, 2007 12:17 pm

OK, so in that case all that I would have to do is input 4800 baud into pin 7 and I'm good to go?

jeroen · Post by **jeroen** » Mon May 21, 2007 12:21 pm

Euhm not quite. Then the clock would have no use, since it's not in sync with the playstation. You'd have to overclock the ps.

nonzero · Post by **nonzero** » Mon May 21, 2007 12:35 pm

Not connecting to a PSX/2. I need the controller to function as it normally does with the Data pin outputting at 4800 baud.

jeroen · Post by **jeroen** » Mon May 21, 2007 2:59 pm

could you speak in hrtz and not baud. Usually people say hrtz. (I don't even know what bauds is?)

Post by **gannon** » Mon May 21, 2007 3:11 pm

Actually, for the most part with serial tech, baud is the preferred rate unit. Also, baud/hertz don't always have a constant conversion (it depends on the serial packets or something along those lines).

Edit: Although I must say, I prefer hertz over baud

jeroen · Post by **jeroen** » Mon May 21, 2007 4:05 pm

Just asking if he could do so. (make it easier for moi)

timmeh87 · Post by **timmeh87** » Mon May 21, 2007 10:28 pm

too fast for what? 250k isnt really that fast. I mean, its at the higher end of the rs-232 spectrum, but a microcontroller in the MHz should handle it just fine.

and that would also be my answer: if you really need to, get a microcontroller and just drop about 9 out of every 10 packets. the tradeoff of course is a loss of resolution.

you'd probably also have to drop them more intelligently than just randomly.
ie. if the data frame goes across 4 packets then you would be dropping 36 consecutive packets out of 40, starting on a frame boundary.

but overall it only sounds like an afternoon of work if you are already set up to do microcontrollers.

now after all of that has been said... cant you just give it a slower clock, since its not plugged into a ps2 anyways?

i think so.

http://www.gamesx.com/controldata/psxcont/psxcont.htm

nonzero · Post by **nonzero** » Tue May 22, 2007 1:10 pm

timmeh87 wrote:cant you just give it a slower clock, since its not plugged into a ps2 anyways?

That would be perfect, what parts do I need to make this happen?

The other components required for my project are all in place, aside from the essential one of getting the PSX controller to work and process as it normally does but with it's output (Data line, pin 1) at 4800 baud (or Hertz for those that prefer

).

Thanks

Post by **marshallh** » Tue May 22, 2007 3:18 pm

Most likely it's fixed at a single speed. But, it might adjust to match the speed of whatever device it's communicating with.

I think we can help you more if you explain why and what you need a 4800 baud PS2 controller for.

jeroen · Post by **jeroen** » Tue May 22, 2007 3:39 pm

marshallh wrote:Most likely it's fixed at a single speed. But, it might adjust to match the speed of whatever device it's communicating with.

I think we can help you more if you explain why and what you need a 4800 baud PS2 controller for.

Well I guess it "adapts" since that's what clock signals are for right? You can prob get it up to something faster. But just don't push your luck . It's stil a processor in there.

timmeh87 · Post by **timmeh87** » Wed May 23, 2007 1:30 pm

jeoren: he dosent want to make it faster.

and is there a processor in there? or just some logic? id imagine its not more complicated than some buttons, a few adc's and a shift register

but yeah. according to that link i gave before, the data comes out in sync with the clock (as one would expect). i dont see anything wrong with using a slow clock.. only way to know is to just try it.

like marshall said, no one can give you much more detail than that unless we know what you are doing.