(Kupid 2.0 Announced) Keyboard for PS1 RPG Maker

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I just got my logic analyzer; I wasn't expecting to get it so soon, being as I ordered it yesterday. ^_^

I still need to learn how to use it, without breaking it. :P But, once I do, I'll begin doing extensive testing of Kupid, trying to figure out how I can make it better.

I'll post some of the graphs/charts and whatever else I generate during the testing so you all can see. I don't know when that will be, but, as always, I'll post updates as soon as I have anything to post.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I've got the logic analyzer hooked up to Kupid and have started doing some basic testing. Pictures below.

The LA hooked up to Kupid:


The letter/character preceding the d-pad press indicator show what character I had typed on the keyboard. Each pulse (represented by a vertical line) is shown over time; so you can see how the duration of d-pad presses differ from the duration of button presses (d-pad presses are shorter than button presses), as well as how much time passes in between pulses. You will also see the extra pause (shown as a larger gap between d-pad pulses) that I put in long sequences of d-pad presses to help prevent misses. The below takes place over 30 seconds. It's Kupid as you've never seen it before:


I still have work to do on it. Wish I could afford a 32 channel LA, but this 8 channel one is still awesome. ^_^

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I've finally managed to record a missed button press. The cursor was on "W" then I presses "1" on the keyboard. As you can see below, all the proper pulses were sent with the correct timings. However, the last LEFT pulse was missed, typing in a "2" instead.



Thanks to the LA, now I know for certain that the pulses are all being sent, and that it isn't my program or circuit that causes the problem; not directly, anyway. The next step in figuring out what causes the missed presses is to monitor the signal being sent from the PS1 MCU along with monitoring the signals sent from the Kupid circuit and seeing what happens on the data lines when a button pres is missed.

I'll need to take a look at the schematics of the PS1 controller to figure out which lines carry which info, so I know what to monitor.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

Made some good progress. It has become clear that the way the PS1 controller transmits data, at regular intervals, poses a potential problem for my Kupid design. I'm not certain yet, mind you, but I'm beginning to get a grasp on the possible reasons behind the button misses.

I've figured out the protocol that the PS1 controller uses to transmit data to the PS, and am looking at the bit-level data transmitted to try and work out what is really going on inside Kupid.

Below is a picture of the bit-level logic graph of a single PS1 data transmission, which takes place over a time span of 299 microseconds. The white text the hex value of the data being transmitted.

Basically, the PS sends out a signal that it is ready to communicate with the controller by bring the Attention line LOW. Then it sends out $01 then $42 saying it's ready to receive data. The controller sends out $5A, telling the PS that it's about to send the button press data. The button press data is sent in two bytes, with each bit corresponding to a certain button. In this case, the button presses is LEFT, so the controller sends the first byte, $00, then the second byte $BF.

I'm still working on breaking down the signals, and trying to record a missed button press along with the PS1 data lines.

While this may tell me a bit about why buttons may be missed, it doesn't mean that I'll be able to use that knowledge to improve Kupid. So, for the time being, I'll just say that we'll see how it goes.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I thought about the problem some more, and think I may have figured out why the button presses are being missed - it has to do with signal timings, which turned out to be quite a lot smaller in duration than I had figured (i.e. on the microsecond scale). I won't go into the details, as it's just a theory at this point. I still need to collect and analyze more data to see if it really is the reason.

If so, then I think I may have come up with a way of potentially solving the problem. Basically it involves monitoring the ATTN line on the PS1 controller, and using that signal to control the timing of the button presses. However, we're dealing with a timespan of a couple dozen microseconds at most, so this solution may not work out. If it does work out... well, I'm loathe to say anything. Suffice to say that if it does work out, then the problems with both accuracy & speed will be a thing of the past. Just don't get your hopes up quite yet.

In short, my new LA has opened up all kinds of new possibilities for me to improve Kupid. Whether or not those possibilities will pan out, I can't say. Regardless, I'll post more detailed info with, no doubt, more charts & pictures as the testing/analysis progresses.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

My theory was correct. I've recorded several missed button presses and figured out what's going on.

Every 1.8 seconds, the duration of time which exists in between each ATTN signal pulse of the PS1 controller doubles from 16 milliseconds to 33 milliseconds for three to four pulse cycles. The extra long in-between time on the ATTN line is time when the controller will not read any button signal at all - so, the signals are being sent by my PICAXE, but the PS1 controller isn't listening.

In my earlier testing, I set the d-pad pulse time to 17 milliseconds in duration, and the button-press pulse to 70 milliseconds. The button presses are never missed, but the d-pad presses are. 17ms turned out to be very close to the natural pulse cycle of the PS1 (I didn't know that then, but basically stumbled upon it even before I had my LA), so it worked really fast 90% of the time, but missed 10% - now I know why.

This is because any d-pad pulse duration less than the maximum potential gap between the PS1 ATTN pulse cycles (33ms) will sync most of the time, but will fall into an extra long gap between the ATTN signals if the pulse from the PICAXE just happens to be sent during that short period of time that the ATTN pulse cycle spacing has doubled. This period of time when the d-pad press will be missed lasts for 100ms every 2 seconds. This would have been utterly impossible to figure out without a logic analyzer.

Okay, so.... you probably didn't understand that. :P In a nutshell, I've figured out why the presses were being missed. I've adjusted the button signal timings, and made a few other modifications to the program to sync it up to the ATTN signal to counter-act the odd timing issues.

AND.... I believe I have completely eliminated missed button presses. Kupid is now 100% accurate! (barring any noise on the line, circuit wonkiness, loose wires, etc.)

All I have to do now is fix the power issue (which is not a small problem), and my design for Kupid will be done!

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I just got the new step-up board. I'll be doing some soldering and whatnot for a bit, soon. Once it's in & tested, the Kupid prototype will be done.

Once that's done, I'll do a bit more thinking about Kupid, then start designing the PCB and get the first production model built.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

Video of the final hardware & software in action - http://www.ustream.tv/channel/kupid-testing

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I have finished Kupid. It is 100% accurate, nice and speedy, and will be available for pre-order shortly.

More info will be posted in a couple days, as I finalize all the design details, and get the price set.

Check out the latest video (linked to in my sig, the Live Stream link) to see Kupid in action.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

Here is the final schematic for Kupid:

http://rpgmakerxp.us/assets/Kupid%20Schematic_final.png

• Price: $35 + Shipping (the cost of shipping depends on where you live, ~$10 is a fair estimate).
• The payment method will be PayPal.
• The lead-time for an order of a single controller may be as much as two weeks (lots of wires to solder & test all by hand, and shipping transit time may take as much as 7 days, depending on where you live).
• First-come first-serve (with the exception of the first three units, one of which will be going to Ix & two to Lantis @ the Mag)

Other ordering details will be finalized & released in another topic within a week or so.

I'm off of Spring Break and back to college starting tomorrow, so I don't know how busy I'll be yet.

[Sivart the Sloth Trencher]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I'll have to talk with my folks about this one. I've got no money right now but I really want to support this.

[Jeroak Nelave]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

As i said when you started this project, you get it to work, and i'll buy it, and i will be ordering one as soon as you get preorder info up.

[Thutmose]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

As i said when you started this project, you get it to work, and i'll buy it, and i will be ordering one as soon as you get preorder info up.

I'll open pre-orders once I finish the first production model. So it might be a week or two yet. I'm waiting on some wire, and now have both college & work to contend with. :P

Basically, people will post in a topic (that I'll open later) to reserve their spot in line (first come, first serve) and when I have fulfilled the previous order, the next person will pay (via paypal), I'll make the Kupid unit, and then send it to them.

So, everyone will have to be a bit patient. Ix & Lantis are getting the first three, after those are made, then the first person to place their pre-order will get one.

If Valk really wants one, then he can have #4. Just needs to let me know.

[Valkysas]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

I would love one, but I am broke. I'll order one later on.

[Jeroak Nelave]

Re: (Prototype Now Functional) Keyboard for PS1 RPG Maker

You should make a quick video of the thing in use (unless you did and i didnt see it). I'd love to just see with my own eyes it working like advertised.