tta583
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Posts posted by tta583
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If I am following along the software (game) is looking for some voltage, like right at 5v (Mitch's table, thanks Mitch!).The paddle inputs do NOT sense analog voltage. They simply indicate whether the voltage on the pin is above or below a certain threshhold, and allow a means of grounding it. In addition, there is a cap tied between each paddle pin and ground.
The effect of this is that when the grounding circuit is released, the cap can charge through the paddle controller (if one is plugged in). Software can then watch to see how long it takes for the paddle pin to reach the switching threshhold (if it ever does) after releasing the grounding circuit.
In a 7800 controller, pushing one of the fire buttons will connect the "main" fire button pin to a paddle pin; the paddle pins also have 680 ohm pulldowns within the controller. Because the pullup on the fire button in anything other than a 7800 in 7800 mode is fairly week, it can't pull the paddle pin anywhere near the switching threshhold, and thus software can't see anything useful on the paddle pins. In 7800 mode, there is an extra-strong pullup on the fire button pin; it will overpower the 680 ohm resistors and get the paddle pins up to the switching threshhold.
OK, that makes sense, but (Now here is where I hi-jack my own thread and head off in a different direction!!) I am a little fuzzy on the function of the paddle controller when using a real paddle. I would have guessed it detected an analog voltage, not just a voltage, so that it could detect just where in the range the paddle was. So how does it know you are going right, left ,etc. and when you stop?
Oh, and just so that I understand the terms:
In 7800 mode, there is an extra-strong pullup on the fire button pin; it will overpower the 680 ohm resistors and get the paddle pins up to the switching threshhold.
When you say over powers the resister to me that means you have enough pullup voltage that even with the bleed off to ground through the resistor there is still enough "left over" to get the paddle pins up to the switching threshold. Is that right?
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One thing I'm not sure I understand yet (and forgive me if this is a stupid question or if it's already been explained elsewhere) ... if the 7800 is capable of detecting when the paddle inputs are pulled to ground by the dual action buttons, would anything prevent other Atari systems that use paddles (the 8-bit computers, for instance) from doing the same thing? Could there be games for the 2600 or the 400/800 that use both fire buttons independently, or is this something unique about the 7800 that the other machines cannot replicate?
Humm, that is a good question. Now, if I understand this correctly I "think" you have it backwards. The paddle controllers , or rather the pin to them, are pulled up when a button is pressed. It was posted above that the controllers read a voltage to determine movement, or actually a range of voltages controlled by the pot in the handset. If I am following along the software (game) is looking for some voltage, like right at 5v (Mitch's table, thanks Mitch!). I would guess that the game has to be programed to have the controller look for close to the max value as, since it appears to be a floating circuit, it could pick up some interference and fluxuate some all on its own. Looking for "any" value in the paddle controller my lead to false "fires". Make sense or am I off base? If I am correct then I would think the answer would be Yes (given there is not some BIOS type of software in a 7800, or some hardware control available to games (software) in the 7800 that the 8bits lack).
As to the other comments, well at first I was not going to even dignify them with a response but, well, I changed my mind. Here is the deal, I am tyring to teach myself some electronics. I also happen to like and collect Atari. I am looking in to some controller projects as a teaching aid. I also like to understand how things work as opposed to just duplicating them (IE just duping the wiring) If you don't care then don't read the thread. Beyond that, thanks to the others who are chiming in and helping out!!
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Why yes, I think it does!! The table shows, I think, what is being discussed. Let's see if I can get this...talking it out again.
The directions are pretty much straight forward. P1 through 4 are pulled up (5.0 for 1 and 2, about 3.5 for 3 and 4). When a direction is pushed you short to ground (p8) and the given voltage goes low (.1-.2) which is detected by some IC in the console.
Now to the buttons. In 7800 mode p6 is high (5v). A button push shorts 6 to 5 or 9, depending on the button. Given the previous conversations I am going to say going high on 5 or 9 is then "detectable" by the paddle controllers and registers as a button push for software (game) written to watch for this. Up to this pint 5 and 9 were floating (no specific pull up or down). Guess here (the learning part!) that this is the case because of the 2 paths, strait up the pin (5 or 9) or through the resistor, the path up the pin is favorable (no resistance). Now in 2600 mode the console end of pins 5 and 9 are switch open. When a button is pushed there is one path to ground, through the resistor, which is then detectable by the old school 2600 method when pin 6 goes low.
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Not a problem!! I try to give back what I can, even if it is just a little. I know the good old Internet, via boards like this one, has saved me tons of work. I figure someone else out there may benefit from some of mine. If for nothing else I find myself going back to forms a lot to figure out how I did something 6 months ago!!!
Also, tried the code tags, it did not clean it up. The funny thing is that if I go to edit the post it shows up just fine in the edit form???
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OK, I "think" I am getting this. Please bear with me, I am teaching myself this stuff as I go along. Taking it out helps me!!
First off, after posting it occurred to me there was a paddle issue here I was not factoring in. Where can I get a map of the pins for the paddle?
It's a bit more complicated than that. Whoever designed the control scheme was willing to add some complexity to the console to minimize cost on the crontrollers.
In 2600 mode, the fire button pin has a "normal" pullup on it. The paddle inputs will typically be floating, but they may be pulled down hard to ground depending upon what software writes to the VBLANK register. The normal pullup is no match for the 680 ohm resistors; when either button is pushed, the fire button input will be pulled down enough to register a clean "low"; the paddle input will be pulled up a little bit, but not enough to register a "high".
I was just reading on pullups, downs, and "floating" as luck would have it. OK, so if I follow along in 2600 mode pin 6 is pulledup, or fed a constant voltage so that it is a definite high. I am guessing there is an IC in the console, at the other end of pin 6 registering that high and waiting for a low to trigger it?? I am going to guess 5v is the pullup value? Push the button you connect through to the 680ohm resistor. Pin 6 is pulled up with enough voltage that, despite the resistor, it gets pulled low enough, to ground via pin 8 out the back of the 680, to register a low.
In 7800 mode, the fire button will get a much stronger pullup. This pullup will overpower the 680 ohm resistors. If the paddle inputs are floating, they will register a fire button push, but the "normal" fire button input will not. If the paddles are switched to ground (using VBLANK) or if a 2600 joystick fire button is pushed, the "normal" fire button input will see a "low", but the paddle inputs will see nothing.
Clever design, though my own taste would have favored adding a transistor and a couple more resistors to each controller.
Now in 7800 mode you have a larger pullup, as you said. It will, again, or can, overpower the 680 if connected through via button push. You said if the paddle inputs are floating.. I am guessing the paddle inputs are 5 and 9? Floating meaning they are give no specific pullup (fed a voltage) or pulldown (forced to a ground). This is decided via programming, correct? Now for the how it works part...If they are floating then you can use the paddle inputs to detect button 1 or 2. The 2 paths are to ground via the 620 or back up 5 or 9. 5 or 9, depending on the button, would be the path of least resistance so the paddle inputs, on the other end of those pins, detects the "button". Following through if you (the program) switch the paddle inputs to ground (grounds pin 5 and 9) a button push will just flat out ground pin 6 leaving the logic at the head of pin 6 to be able to detect the push.
Sound sort's maybe about right?
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I mentioned in an earlier post that I was thinking of using cables from some old Sega Genesis 3 button controllers as they are 9 pin ends and appeared to wire all the pins. Getting the entire controller dirt cheep sort of clinches the deal. Anyway, I finally got a chance to pull one apart and test the cable. Below is the pin out of the 2600/7800 controller from the FAQ. Tacked on to the right is the wire colors for a given pin in the Sega Genesis cable. It is worth noting that I did not bother to test the function of the given wire. In other words pin 1 in Atari land is up on a white wire. Pin 1 in Sega land is Brown but I have no idea if it up, left, fire 1…etc. BTW, when looking at the diagram of the connector end it is from the point of view of holding the connector in your hand and staring into the holes. (Diagrams such as this on the Internet always mess with me as don’t know if it is with respect to looking in to the cable connector or looking at the plug on the console.)
2600/7800 pinouts:
_________________
\ o5 o4 o3 o2 o1 /
\ o9 o8 o7 o6 /
\___________ /
pin # 2600 control 7800 control Sega 3 Button wire 1 WHT- Up WHT- Up Brown 2 BLU- Down BLU- Down Red 3 GRN- Left GRN- Left Orange 4 BRN- Right BRN- Right Yellow 5 unused RED- Button ®ight (-) Green 6 ORG- Button ORG- Both buttons (+) Blue 7 unused (+5v) unused (+5v) Grey 8 BLK- Ground(-) BLK- Ground(-) Black 9 unused YLW- Button (L)eft (-) White
Darn it, the spaces were left out.... here are the Sega colors alone by number
pin # Sega 3 Button wire
1 - Brown
2 - Red
3 - Orange
4 -Yellow
5 - Green
6 - Blue
7 - Grey
8 - Black
9 - White
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I have been messing around, as of late, with converting some digital 2 button capable controllers in the spirit of Stargunner’s wonderful Radica Space Invaders TV Game to 7800 joystick conversion.
http://www.atariage.com/forums/index.php?showtopic=72198
Given the pin out and button diagrams from the faq:
http://www.atariage.com/7800/faq/index.htm...mID=7800#cat2_9
I can easily recreate the circuit but I have a question on the function of the bottoms. In a typical 2600 stick, and when looking at the compass direction of the 7800, all the functions are detected by shorting a given wire to ground. For example short pin 1, the white wire, to ground at pin 8, which is the black wire, and the console knows the player is pushing UP on the stick. Same deal on the 2600 single fire button, connect pin 6 (Orange) to 8 (blank) = FIRE!!!
What is going on with the buttons in the 7800?? There is an unused pin (5 or 9) that could have been use to “ground” the 2nd button so that it worked just like all the other pins. Instead we have this weird path back to the console. As I read the diagram in the FAQ a button press connects through to pin 9 or 5, depending on the button, AND that 620ohm resistor. To me you are taking what ever voltage is on pin 6, dumping some of it to ground via the 620, but allowing the residual back to the console (via 9 or 5 depending on the button). Is there some IC or something or other that uses this signal back from the controller for something??? I am guessing that it is used for something since the buttons do not short directly to ground like all of the other functions.
OR…am I looking at this in the wrong way. Does the 7800 want the feedback to the console, as opposed to a short to ground, to detect a button push thus the resistor is there to make that path the path of least resistance when in 7800 mode. In 2600 mode does the console “open” pins 5 and 9 (infinite resistance) so that, even with the resistor, the buttons go to ground as that is now the path of least resistance and, thus, function like a 2600…..or am I just thinking to much into this????
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Oh yeah! Well about a year ago this guy opened up an arcade machine store here in Louisville. He has a lot of great machines (a Black Widow, Sinistar, and Tempest among others) and does a lot of good work restoring and repairing them. We've been in there a number of times and drooled all over the place. We almost bought a Pac-man machine back during the holidays, but he sold it before we could get to it. So when this one showed up, we jumped on it. Got same day delivery for free! He's a really cool guy and knows his stuff!Very happy with our purchase!
Is that the guy over on Bardstown road? Across from BW3's.
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The original Genesis uses a standard coxial power plug (barrel style) with a 2.1mm Inner Dimension X 5.5mm Outer Dimension the most common coxial plug around. If you can solder at all, you can buy these solder type plugs at Fry's for less the $1 and hook it to (solder it on) any 9vdc~10vdc supply (1amp or more preferably) you got around the house. Just make sure you make it tip negative/ground positive (this is backwards from most supplies) or you'll probably fry your genny, as it doesn't have a rectifier or diodes to protect it from reverse polarity. Most power supplies have a white stripe/dashed line on the positive wire, but by no means all and you may need a multi-meter to determine its polarity. In fact you may already have a suitable supply around (like your cordless phone, especially panasonic brand) be sure its tip negative and ~9vdc and see if it fits the plug on the genesis. If the supply is rated at less than 1 amp it'll still work, just don't use it for long periods of time our you'll ruin the p/s, but not the genny.Tip negative looks like this on the supply, somwhere on back of it usually, and be sure its 9vdc not 9vac (ac supplies don't have polarity
):(-) ----o)----(+)
Alright! this was the kind of information I was looking for. I was surprised I couldn't find it out there on the web. I did search. Thanks for the great info.
I just went through this. I have a Gen1 but just got another Gen1 mounted to a Sega CD. Unfortunately it had no accessories or either PS. I borrowed a PS from a friend who had the same model Sega CD to see what it required. It turned out that it was the same as a Gen 1 PS used in the console itself. That is also when I discovered the 9v or 10v thing. The PS I had on my original Gen 1 was 9v, his was 10v. At first I thought that it may have something to do with the CD unit wanting 10v . I soon discovered that the part number on the 10v units have a -1 or -2 (I think it was) after them. The 9’s have no dash. Important…well no. Most wall wart power supplies are “close” to their rated output but never on. All the Genesis PS’s I have metered, regardless of part number or marked output put out “around’ 10v. In my case the Gen 1 and Sega CD work just fine with either a 9v or 10v PS. The important thing, as mentioned is tip, how its wired, and the amp rating. You need at least 1.2ma. All the power supplies I looked at, 9v or 10v, were 1.2ma. Any less will work the PS to hard and would probably lead to its eventual death.
As for a source, well I was just going to make one up so I stopped in my local Radio Shack for a tip. Turns out they had some close out purpose made and labeled Sega Genesis power supplies. They were $8.50. I hated paying it as I typically get a PS from a thrift in the$3 range but I figured the extra would more than even out in my time. Do you have any Rhino game stores around? They are like Game Stop. I just so happened to wander in one by me and they had about 6 Genesis PS for $4.95. They also sell 3 button controllers for $1.99. I ended up getting a spare rue Sega PS as well as a couple controllers as I needed parts donors for an Atari 7800 joystick project.
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Based on this:
http://www.atariage.com/7800/faq/index.htm...mID=7800#cat2_9
and assuming your numbers match those of the diagram I would say the colors are diffrent between the 7800 and Sega cable. If the pin numbers are the same it sounds like we need a 7800 to sega cable cross.
For example
Pin Atari Sega
1 Wht-Up brown
Etc... Again, assuming same pin numbers.
Speaking of I just picked up 2 3 button Sega controllers for 1.99 each so that I can make a set of controllers. I have one apart already but did not get to test it so that I could map the colors.
My only real problem is what to do with all the resistors. I stopped at a local electronics supply store and ended up with a 100 pack. At least they were cheep, I guess....
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I'm glad you brought this up, it sparked a memory. Any idea where I can get diagrams for a 64 and a 1541 drive? Perhaps a good C64 discussion boards? I have been thinking about pulling my C64 out of the closet for a little while now. This one is not a thrift store find, its my original unit from back in the day before I got my first PC. Complete with all my games, my old FastLoad, a 1541, a 1541 II, and a monitor and God only knows what else I shoved in that old box (Actually, the same box that first PC came in. It was kind of like a changing of the guard that day.)
Anyway I recently picked up a few loose carts, 2 1541's, and a tape drive (had not messed with one of those since I had a VIC). One of the 1541's powers up but never did the startup head seek that I remember. I soon smelled smoke. When I opened it up I found the failed component, a small capacitor I think it is. Should be easy enough to fix unless it is the symptom of a bigger problem.
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OK, well I failed to do myself what I always suggest as the first course of action....gotta' love good old google:
http://pinouts.ru/data/genesiscontroller_pinout.shtml
Looks like a sega use all 9 pins, so the cable has all nine wired. No clue what the colors are but that is what a meter is for!!
Guess I need to snag a couple cheep Sega pads and see if I can crush them together with a RSI.
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Speaking of parts donors, does anyone know if the Sega Gen pads, the 3 button ones, have all 9 pins wired in their cables? I can get a handfull locally for cheep, like less than the cable alone.
Thanks,
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Thanks, I looked and looked. The Radica rings a bell, I think I saw it as I was scanning and it just never clicked----plus I obviously did not read the rest of the subject.
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Hi all,
New to posting here, been lurking around for a while. A few days ago I saw a thread on converting a Space Invaders TV game from Game Stop to a 7800 joystick. Any one have a link? I can not seem to re-find it? I picked up one of the games and am sure I could figure it out on my own but I would like to take another peek at the origional.
Thanks,
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Building a Better Proline
in Atari 7800
Posted
Check this out as a good alternative to the ProLine:
http://www.atariage.com/forums/index.php?showtopic=72198
I just built one, man its great. It would be a lot easier than moving around the internals of the existing stick. You get nice positive micro-switched directions, its self centering, good for the lefty or righty, and 2 buttons. I ended up using a Sega Genesis cable from a standard 3 button controller. I was able to get several of the controllers for (literally) a couple bucks each. They have all 9 pins wired but the colors are different. I mapped them and made a post in the above thread. The only downside to the cable (for me) was that they are a little funky to strip back as the conductor is sort of soft and flimsy. It took some practice to strip the ends without ripping out the strands.
I found this type of wire strippers to work the best for me:
http://www.allelectronics.com/cgi-bin/item..._STRIPPER_.html
You can adjust the stop in the handle down to the specifics of the wire. You can get them at most any home improvement store.
As to the resistors, well I had a similar question. I wanted to know how it worked instead of simply duplicating the circuit. That discussion is here:
http://www.atariage.com/forums/index.php?showtopic=84963
In a nut shell the 7800, in 7800 mode, uses feedback from the buttons up the 2 paddle controller pins to sense a fire button. The resistors keep from shunting the fire button positive (orange wire I think, but don't hold me to that!!) straight to ground. In 2600 mode the 7800 will open the console side of the paddle pins so that the fire buttons go to ground, via the resistor(s)......at least as I understand!!!
Brent