[HN Gopher] The Original "Universal" Port by Atari
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The Original "Universal" Port by Atari
Author : schmudde
Score : 36 points
Date : 2022-08-31 15:22 UTC (7 hours ago)
(HTM) web link (tedium.co)
(TXT) w3m dump (tedium.co)
| protomyth wrote:
| That port was the reason I learned to solder and how photocells
| worked. I put two photocells on the paddle pins and wrote
| programs on my Atari 400 that used the light levels to do things.
| I think the original project was in Antic Magazine. It was about
| recreating a sound device used in 50's scifi films. I used it
| later to detect if the someone was in the hall during a summer
| program to give us a bit of warning. Fun projects that are pretty
| damn hard with USB and modern programming.
| Turing_Machine wrote:
| > You probably never noticed this, but physically, an Atari
| joystick port is just a serial port with a lightly modified
| design
|
| It's not any kind of serial port, modified or otherwise. What
| makes a port "serial" or "parallel" is the way the data is
| transferred, not the shape of the connector.
|
| Each joystick signal (up, down, left, right, trigger, paddle A,
| paddle B, plus power and ground) has its own pin. That makes it a
| parallel port.
|
| Now, the Atari SIO port, mentioned by another poster, and used to
| connnect peripherals (such as disk drives and printers) _is_ a
| serial bus, but the joystick port is parallel.
| jweather wrote:
| I found this out for myself as a kid by taking a 2600 joystick
| apart to figure out how to wire it to my LEGO Mindstorms kit.
| By carefully choosing resistor values for the four cardinal
| directions, I could read 8 unique resistance values out for the
| cardinal and diagonal directions at a single analog I/O port on
| the RCX brick for control. It was a huge boon to me that it
| used simple contact closures and not a digital serial protocol!
| lstodd wrote:
| More than that, paddles are actually analog signals. So it's
| neither this, nor that or two in one, the second not being
| serial ofc.
| keithnz wrote:
| The ports were great, they exposed both input/output pins. Back
| in the 80s, as a kid, on my Atari 800XL I used these ports to
| interface to electronics and used my computer to control real
| things! This significantly influenced what I wanted to do and
| sent me down the path of doing embedded systems / control
| systems. Even though these days I mainly do backend/web type
| things, I still do a bit of embedded programming.
|
| The port/s details can be found here
| https://en.wikipedia.org/wiki/Atari_joystick_port
| Findecanor wrote:
| I put together another article about it on a input device wiki:
| https://deskthority.net/wiki/Atari_interface
|
| This contains more technical info on the pinouts, the signals
| and how different devices and systems are incompatible. I had
| written it in preparation for building an adaptor for myself,
| and I have identified a few issues to watch out for.
| jhallenworld wrote:
| So D connectors themselves are really good:
|
| Versions are available that are acceptable for military and space
| use.
|
| The pins are properly wiping: it means that when you insert or
| remove the plug, the contact area gets wiped (cleaned).
|
| You can get D connectors that use ribbon cables: this is a huge
| advantage, since they can be assembled quickly without hand-
| soldering.
|
| The connectors have screws, so they can be held in place.
|
| They are rated to 300V and at least some of them can handle 9A.
|
| Invented by James Cannon:
|
| https://militaryembedded.com/unmanned/connectors/high-perfor...
| EvanAnderson wrote:
| I thought this was going about the Atari SIO bus[0], which
| literally was a forerunner to USB. The designer of the SIO bus,
| Joe Decuir, gave a talk at VCF East 2019[1] in which he spoke
| about SIO leading up to his work on USB (and, if memory serves,
| being used to quash a patent troll).
|
| ---
|
| As an aside re: the Atari joystick "standard": I have an Atari
| Flashback 10, which accepts Atari-style joysticks. The sticks
| that come with the unit are flimsy so I broke out some old Epyx
| 500XJ controllers from my youth to use. Unfortunately, that meant
| losing the on-controller buttons for game reset, game select,
| "rewind", and "menu" (which are implemented as "illegal"
| controller states-- up and down simultaneously, etc).
|
| On a lark I plugged-in a female to dual-male DE-9 Y adapter I had
| laying around and discovered that I could just connect both the
| stock controller with the fancy buttons and my 500JX
| simultaneously. I suppose it shouldn't have surprised me, given
| the simplicity of the interface (just normally-open switches). It
| was a nice hack to get both the on-controller buttons for
| emulator control and a good joystick.
|
| [0] https://en.wikipedia.org/wiki/Atari_SIO
|
| [1] https://www.youtube.com/watch?v=dlVpu_QSHyw&t=2296
| spacedcowboy wrote:
| Yep, I was of the same mind, fully expecting this to be SIO,
| not the joystick port. SIO was really ahead of the game for its
| time.
| nsxwolf wrote:
| Texas Instruments had a similar standard from around that time
| called HexBus, but it didn't make it out into the wild after
| they ended their home computer division.
|
| [0] https://en.wikipedia.org/wiki/Hex-Bus
| Turing_Machine wrote:
| > I suppose it shouldn't have surprised me, given the
| simplicity of the interface (just normally-open switches).
|
| Sure. Even normal use allowed multiple switches to be on to get
| diagonal motion ("up" and "left" simultaneously, say), if I
| remember right. Using states that can't normally occur (up and
| down at the same time) to add extra functionality is a pretty
| clever hack.
| jerrysievert wrote:
| I miss my Epyx 500XJ - thanks for the memories!
|
| though mine had broken a few times, and was soldered and glued
| back together various times.
| neilv wrote:
| The TI-99/4A joystick port fit an actual D-sub connector.
|
| As a child, I made a kind of breakout box for the joystick port,
| using a standard connector, project box, and screw terminal
| strips. For very simple interfacing with normally-open switches.
| (Arduinos and RasPis are much better.) First applications were to
| build a burglar alarm, and grade school computer voting station.
|
| (This was pre-Internet, and pre-modem, and no docs to speak of.
| Somehow, I didn't break the family home computer, despite blindly
| shorting unknown pins, and with no knowledge beyond what I could
| understand of the Forrest Mims intro electronics book.)
| nsxwolf wrote:
| The port is a modified Atari port - they wanted to sell you
| their own joysticks, and save on a port, so they came wired
| together into one port. I had a Y-adapter that let you use
| standard joysticks.
| chasil wrote:
| The 99/4 architecture was quite locked down, so I'm surprised
| that you implemented the burglar/voting applications over/with
| it.
|
| I think the BBC Micro was the most powerful platform of this
| class, but the C64 was the most popular in the U.S.
|
| I wish that TI had stayed out of the home computer market. The
| 9918(a) video chip was really the only real advantage for it.
| Their mismanagement took other players down with them.
| neilv wrote:
| TI BASIC was pretty neat, but you hit brick walls once you
| did everything you could do with character definition
| graphics -- unless you could afford the additional cartridges
| for assembly language or Extended BASIC. And then the
| seemingly unobtainable expansion hardware if you wanted a
| modem or floppy drives.
|
| Before family bought anything, I wanted an Apple II-
| something. We went to the "Apple store" (IIRC, a small
| utilitarian office/warehouse space for school AV equipment
| seller, trying to turn into a computer showroom for parents),
| but when my parents saw the sticker price, IIRC, it was 10x a
| TI.
|
| In hindsight, a C64 would've been the best choice around the
| same price point as the TI, but parents couldn't have known
| that at the time. TI was marketing like crazy, with lots of
| talk of education software (which we never saw), and the
| unspeakable celebrity endorsement. There were also a lot of
| worse choices parents could've made.
| AnotherGoodName wrote:
| This was always great for having a second controller. You might
| have had a master system and your friends an Atari or c64 but you
| could always take your controller to their house and play.
|
| The $20 it cost for a second controller was a lot back then.
| randombits0 wrote:
| Back in the day, the Atari 1030 modem (1200 baud, I believe) was
| Hayes compatible but did not have a ring detector. That makes it
| difficult to use it for a BBS.
|
| So I ended up using a neon lamp across tip and ring to light up
| when the AC ringing signal hit. I placed it next to a photo
| resistor and hooked it up to the fire button on one of the
| joystick ports. The resistance didn't drop to zero, but it was
| close enough.
|
| Two components with the bonus of optical isolation from the phone
| network!
| snvzz wrote:
| Beware Mega Drive / Genesis controller has somewhat different
| wiring in a way that could destroy computers. It e.g. shouldn't
| ever be connected to a Commodore 64 without an adapter.
|
| An open source design for an adapter exists.
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