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Hi,

 

I'm thinking about a device with more than 8 GPIO (general purpose I/O) outputs on two joystick ports, i.e. like an inverse multijoy with four 4-bit latches connected to port 0, selected and latched by port 1, resulting in 16 outputs to control external devices like lamps or motors, etc... I have a vague memory that such a device already exists. Does anybody know what I'm talking about?

 

Regards,

Ivo

 

Edit: I call it GPIO but I'm only talking about outputs :)

Edited by ivop
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Hello Ivo

 

Atari User magazine (from the UK) had an article on how to build a device that could switch a couple of devices/power outlets via PIA. Not sure if that is what you are remembering.

 

And Happy Computer from Germany had something like that in one of their Atari Specials IIRC.

 

Sincerely

 

Mathy

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I posted some links on this some time ago about using the Atari for automation, but my memory is poor today, perhaps another day I will remember for you, or someone will find it in the meantime...

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Hi,

 

I'm thinking about a device with more than 8 GPIO (general purpose I/O) outputs on two joystick ports, i.e. like an inverse multijoy with four 4-bit latches connected to port 0, :)

Would anything prevent MultiJoy from running ‚inverted‘, i.e. using it to select the various joystick ports but programming the one on the Atari that‘s now used to read inputs to sending output instead?

 

 

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The Atari Lab was something like that.

This is what I use AtariLab Interface for. I have one at the moment, but intend to get several more, 2 for use with my XL and 4 for use with my 800. All that is needed to control motors or turn external things on and off are RCA jacks instead of wiring up special controller plugs to do it. A bit bulky, but much simpler. The only I/O the AtariLab Interface doesn't have on it is for the joystick fire/trigger button, but it has 2 +5V I/O's so I converted one to the fire/trigger button and if I need additional +5V connections I just use an RCA Y-splitter on the one remaining. I also added a power switch to the AtariLab Interface, as I hate devices that don't have them. A link below to my initial investigations.

 

http://atari.boards.net/thread/3011/experimenting-atarilab-interface-intended

Edited by Gunstar

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Thanks for all the reactions! Fairly sure it was Atari Lab. I'll look into it. Any schematics available?

 

 

Would anything prevent MultiJoy from running ‚inverted‘, i.e. using it to select the various joystick ports but programming the one on the Atari that‘s now used to read inputs to sending output instead?

 

The problem by using the MultiJoy "inverted" is that the outputs are not latched and basically all connected, which is fine for input, but not for output.

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yeah you get that on boards that insist you register and that crap before they will let you see a thing... i just move on... I don't play that jazz..

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Yes, I forget that sometimes...and I agree with The Doctor, but I'm only a moderator of the board and membership requirements required for some areas of the board isn't in my power. But it's a good board, Admin is Brenski, and in this case it's worth signing up. But all my Atari projects I do threads on over there because I'm a moderator and because it's a board better suited to such things with more specific sub-forums, and there isn't so much traffic where threads disappear down the page on a daily basis and you don't have to use the search engine to find stuff, which is pretty worthless in my experience here on AA anyway...

Edited by Gunstar
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The tricky thing with the forum search facility is that you have to click the box first and type a search term. A lot of people don't even get that far. :D

 

On a serious note: Google also works, and I'm sure Albert would be interested to hear any genuine feedback or suggestions regarding the forum search facility, perhaps via the site feedback sub-forum.

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The default mode of the search is very limited in time frame.... you have to go down and click on the calendar interface for the start and end of the range, making sure to go all the way back to a really early date. You have to use that, for the year month and day or it won't take... a painful click fest..

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I looked into Atari Lab and it's just an easier way to connect to the existing pins and does not extend the input (multijoy) or output (which I'm looking for) capabilities.

 

Unless somebody knows an existing solution that gives you more than 8 outputs, I guess I have to fire up KiCad again and try to come up with something ;) And perhaps I should look into a hybrid of some sort between multijoy inputs and combine that with 4x4=16 outputs, making it a generic 16 GPIO board. I'm not sure it will be backwards compatible with multijoy8, or maybe it will if I can figure out a way to use the inverted enable bit to select outputs? Anyway, food for thought.

 

Edit: if it's possible to add outputs to multijoy8, without interfering with its basic working, that would result in 32 GPIO lines!

Edited by ivop
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My son's just working with shift registers at school. My electronics knowledge is very limited but that would seem like a possibility to have quite a lot of output pins (but would need an entirely separate multijoy-like way to process inputs).

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Hello Ivo

 

Not everybody needs 16 outputs. Maybe you can make the interface cascadable, so you can start with 4 or 8 outputs and cascade multiple interfaces (which are all mechanically and electronically the same) to get up to 16 outputs.

 

Sincerely

 

Mathy

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I looked into Atari Lab and it's just an easier way to connect to the existing pins and does not extend the input (multijoy) or output (which I'm looking for) capabilities.

 

Unless somebody knows an existing solution that gives you more than 8 outputs, I guess I have to fire up KiCad again and try to come up with something ;) And perhaps I should look into a hybrid of some sort between multijoy inputs and combine that with 4x4=16 outputs, making it a generic 16 GPIO board. I'm not sure it will be backwards compatible with multijoy8, or maybe it will if I can figure out a way to use the inverted enable bit to select outputs? Anyway, food for thought.

 

Edit: if it's possible to add outputs to multijoy8, without interfering with its basic working, that would result in 32 GPIO lines!

If you want more than 8 outputs, you use more than one Atarilab. So 16 for XL/XE's and 32 for 400/800's.

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My son's just working with shift registers at school. My electronics knowledge is very limited but that would seem like a possibility to have quite a lot of output pins (but would need an entirely separate multijoy-like way to process inputs).

I read the all the post to make sure I dont replete this!!! Lol ! A pair of shift register ... 16 outputs ... not too bad...

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You could use something like 2 x 74LS259 chips to give you 16 output's and a 74LS151 to provide 8 inputs,

you only need 5 pins to 'address' each bit of the 259 and 4 for the 151 (same 3 can be used for all chips bit select),

so using 2 joystick ports you could do something like this, 16 Outputs and 8 Inputs.

With the right sofware to Multiplex the signals, wouldn't be too hard.

 

 

post-66729-0-21328200-1552233063_thumb.png

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You could use something like 2 x 74LS259 chips to give you 16 output's and a 74LS151 to provide 8 inputs,

you only need 5 pins to 'address' each bit of the 259 and 4 for the 151 (same 3 can be used for all chips bit select),

so using 2 joystick ports you could do something like this, 16 Outputs and 8 Inputs.

With the right sofware to Multiplex the signals, wouldn't be too hard.

 

Thanks for this! I have drawn a few ideas myself, but none has this low a chip count. Not compatible with multijoy, but as a generic GPIO interface this would surely suffice. Could add the remaining trigger and four POT inputs. I suppose it really helps if you know your 7400 series by heart. I am constantly searching for what's available :)

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