How to test my parallel port - 4 way adapter

[Shatterhand]

Hi guys.

I just built myself a 4 players adapter to use with my A600, using the guide from here: http://aminet.net/package/docs/misc/FourPlayerGames_EN


I tested it with WHDLOAD versions of Dynablaster and Great Courts 2, and with ADF version of Max Rally.

In none of the games the joysticks 3 and 4 worked at all. No response from none of them (Well, with Max Rally I need to at least press the button to "confirm" the controller and I couldn't. The other 2 games I didn't had response from either directions or fire button)

I tested the connections of the adapter with a multimeter, they are all ok, so I suspect of a faulty paralell port (Never used it on this system).

Is there anyway I can test it? Any other tips/suggestions?

Thank you

[idrougge]

In these cases, it's usually a case of having looked at the pinout the wrong way around.

[Daedalus]

If you're in anyway decent with electronics and programming, a simple resistor/LED combination can be used to test each pin while software pokes values to the CIA once a second. That should flash the LED on and off and let you try each pin separately. Also, you can set the outputs high and then simply read the inputs as you short each one of them to ground to ensure they respond. The addresses you need are here, specifically set $BFE301 to $FF for output, $00 for input, and $BFE101 for reading or writing values of $00 for low or $FF for high, or any value in between for a mixture in binary. $BFD200 and $BFD000 are likewise needed for the fire buttons, which use two of the status lines on the port (SEL, POUT and BUSY, can't remember which two...)

[Korodny]

Originally Posted by Shatterhand

I just built myself a 4 players adapter to use with my A600, using the guide from here: http://aminet.net/package/docs/misc/FourPlayerGames_EN

I'm the author of that document, we built a (working) adapter using these instructions some twenty years ago.

Did you notice the connectors are shown from behind?

In none of the games the joysticks 3 and 4 worked at all. No response from none of them

A joystick consists of switches that connect an input line to GND. If nothing works, GND would be the most likely cause for your problem. Check your wiring of the GND cable(s). You can also try some other pin on the parallel port: pins 17 to 22 all carry ground, it doesn't matter which one you use.

(Well, with Max Rally I need to at least press the button to "confirm" the controller and I couldn't. The other 2 games I didn't had response from either directions or fire button)

Just to be on the safe side: Max Rally supports Joysticks 3/4 only in multiplayer mode, same goes for Great Courts (and probably any other four player game).

Here's a joystick tester that supports all four ports:

http://aminet.net/package/driver/input/joytester

Here's a different schematic for wiring up the adapter. It's using different pins for GND, but like I said that doesn't make a difference:

[Shatterhand]

No, I am actually terrible at electronics I actually asked a friend with the skills to build the cable for me, because I am really awful at soldering and stuff While I do solder some stuff, I never to try anything like that for my Amiga for fear of screwing something badly, so I prefer to ask friends who know better what they're doing

Yes, the first thing I suspected was the GND line... but the pin is correct in both connectors. Actually everything is correct and I am looking at the connectors from behind (While I am terrible at electronics, I can use a multimeter to test continuity ).

And I also tested all games on Multiplayer mode, of course. Also using a Master System pad (original one), because I am not even sure a Mega-Drive one will work with this adapter because of lack of 5v+ line, but I see no reason why a Master System one should not work.

EDIT: Ok, I tested it with a Mega-Drive 6 button pad with Dynablaster and the player just moves to a random direction even without touching the controller. With the Master System pad I still get nothing, but with the 6 button Mega-Drive pad, I get a random direction.

That's really weird.

[Zetr0]

@Shatterhand

Its good to see you still about sir - and voyaging into the foray of electronics

From your description, testing and the fact its a relatively simple passive affair - the results lend me to believe there is an issue with the parallel port - I would get the multimeter out on that to check the +5v is constant and not dropping low.

It could be as easy as a ferrite bead needing a touch of solder - or it could be a CIA fault - inspection will tell my good fellow.

[Daedalus]

Some 4-player adaptor schematics don't add the +5V line so MD pads, CD32 pads and similar won't work properly or at all. The MS pad should work fine though as you point out, as should standard Zipsticks and the likes.

Try with the bare parallel port and a joystick tester like the one Korodny suggested, and see if you get +5V on the data pins (pins 2-9). If you do, see if you get a response by carefully shorting each of those pins in turn to ground. If you're not getting +5V on those pins, there's a fair chance you have a CIA or motherboard fault.

If you have a little bit of programming ability, you could still try setting the values I posted above and see if the port pin voltages change. If I have time tonight I might knock something quick n dirty together in Blitz to do that for you...

[Shatterhand]

Ok, used the program Korodny suggested, still the same results: No answer from the SMS pad, get RIGHT+DOWN on joy3, RIGHT+DOWN+FIRE on joy4 with a Mega-Drive pad (really weird)

I am getting 4.9 reading from my multimeter on all the data pins. I tried shortening one of the data pins with ground pins 19 and 20, both times the joytester program read correctly with no problems. So I guess my paralell port is ok.

So the problem is either the cable or the joypads. Time to test the cable again I guess.

By the way, thank you a lot guys, I'd be completely stuck without your guidance

Zetr0: I am always around, I just go into lurking mode sometimes Last month I even took my A600 to a retrocomputing fair here, connected it to a projector and played some Stardust on a huge screen

EDIT: Well, tested the cable for continuity again, everything is allright. I have no idea of what's going on here. The SMS pad is also working properly on the Amiga normal joy ports.

[Shatterhand]

I just tried plugging the cable and shortening the directions/fire pin of the DB9 connectors with their grounds.

The joytest detects movement, but its everything wrong. There are 2 different joysticks being detected on different pins of the same connector.

Still it makes no sense that the joystick has zero response.

EDIT: Well, went ahead and tested every pin of my parallel port, everything works as the scheme on the PDF file I guess there's something wrong with the cable, but the continuity tests are all correct.

[demolition]

I built an adapter from this schematic last year and it works fine in Dynablaster. If you have double-checked all connections and are using standard Atari/CBM joysticks, I would try with another Amiga.

[Zetr0]

@Shatteredhand

I built 4 of these Parallel adaptors for the last Replay show that AmiBay attended. If I get time I will dig one out and take pictures for you.

I do travel past Walsoken a couple of times a month - I might be able to drop it by with a flying visit =)

[demolition]

I opened up my adapter and took a couple of snapshots. One of each side of the 25p connector and one of each side of one of the 9p connectors. I hope it will be helpful to compare with yours.

[Shatterhand]

I used a much cheaper cable than you, I used one of those standard LAN cables, the wiring is a lot thinner than the one on those pictures. I can't think of anything else but this.

[demolition]

The gauge of the cable is not important as long as the connections are correct.