The game port is a
device port that was found on
IBM PC compatible
IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. ...
and other computer systems throughout the 1980s and 1990s. It was the traditional connector for
joystick
A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...
input, and occasionally
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
devices, until made obsolete by
USB
Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad v ...
in the late 1990s.
Originally located on a dedicated Game Control Adapter
expansion card
In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus slo ...
, the game port was later integrated with PC
sound card
A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio i ...
s, and still later on the PC's motherboard. During the transition to USB, many input devices used the game port and a USB adapter dongle was included for systems without a game port.
History
![Game port to USB Adaptor](https://upload.wikimedia.org/wikipedia/commons/d/d4/Game_port_to_USB_Adaptor.JPG)
The game port first appeared during the initial launch of the original
IBM PC
The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...
in 1981, in the form of an optional US$55 expansion card known as the Game Control Adapter.
The design allowed for four analog axes and four buttons on one port, allowing two joysticks or four
paddle
A paddle is a handheld tool with an elongated handle and a flat, widened distal end (i.e. the ''blade''), used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered wa ...
s to be connected via a special "Y-splitter" cable.
At the time there was no industry standard for controller ports, although the
Atari joystick port
The Atari joystick port is a computer port used to connect various gaming controllers to game console and home computer systems in the 1970s to the 1990s. It was originally introduced on the Atari 2600 in 1977 and then used on the Atari 400 an ...
was close. It was introduced in 1977 with the
Atari Video Computer System
The Atari 2600, initially branded as the Atari Video Computer System (Atari VCS) from its release until November 1982, is a home video game console developed and produced by Atari, Inc. Released in September 1977, it popularized microprocessor- ...
, and was later used on the
VIC-20
The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PE ...
(1980),
Commodore 64
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...
(1982), and Amstrad's
PC1512
The Amstrad PC1512 was Amstrad's mostly IBM PC-compatible computer system, first manufactured in 1986. It was later succeeded by the PC1640.
Features
Whereas IBM's PC (and almost all PC compatibles) had a power supply in a corner of the main cas ...
(1986). In contrast with the IBM design, the Atari port was primarily designed for digital inputs; its only analog connections were intended for
paddles
A paddle is a handheld tool with an elongated handle and a flat, widened distal end (i.e. the ''blade''), used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered wa ...
, although as there were two analog inputs per port they could theoretically support a joystick. The
Apple II
The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...
,
BBC Micro
The British Broadcasting Corporation Microcomputer System, or BBC Micro, is a series of microcomputers and associated peripherals designed and built by Acorn Computers in the 1980s for the BBC Computer Literacy Project. Designed with an emphas ...
,
Tandy Color Computer
The RadioShack TRS-80 Color Computer, later marketed as the Tandy Color Computer and sometimes nicknamed the CoCo, is a line of home computers developed and sold by Tandy Corporation. Despite sharing a name with the earlier TRS-80, the Color Com ...
, and other popular 8-bit machines all used different, incompatible, joysticks and ports. In most respects, the IBM design was similar or more advanced than existing designs.
Originally available only as add-on that took up an entire slot,
game ports remained relatively rare in the early days of the IBM PC, and most games used the keyboard as an input. IBM did not release a joystick of its own for the PC, which did not help. The most common device available was the Kraft joystick, originally developed for the Apple II but easily adapted to the IBM with the addition of another button on the back of the case. When IBM finally did release a joystick, for the
IBM PCjr
The IBM PCjr (pronounced "PC junior") was a home computer produced and marketed by IBM from March 1984 to May 1985, intended as a lower-cost variant of the IBM PC with hardware capabilities better suited for video games, in order to compete mor ...
, it was a version of the Kraft stick. However, it connected to the computer using two incompatible 7-pin connectors, which were mechanically connected together as part of a larger multi-pin connector on the back of the machine. This eliminated the need for the Y-adapter.
Adapters for Atari-style "digital" sticks were also common during this era.
The game port became somewhat more common in the mid-1980s, as improving electronic density began to produce expansion cards with ever-increasing functionality. By 1983, it was common to see cards combining memory, game ports, serial and parallel ports and a realtime clock on a single expansion card. The era of combo expansion cards largely came to an end by the late 1980s, as many of the separate functions normally provided on plug-in boards became common features of the
motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...
itself. Game ports were not always part of this supported set of ports.
However, the game port was given a major boost in usage in 1989, with the introduction of the first
Sound Blaster
Sound Blaster is a family of sound cards designed by Singaporean technology company Creative Technology (known in the US as Creative Labs). Sound Blaster sound cards were the de facto standard for consumer audio on the IBM PC compatible system pl ...
. As sound cards were primarily used with computer games,
Creative Labs
Creative Technology Ltd. is a Singaporean multinational technology company headquartered with overseas offices in Shanghai, Tokyo, Dublin, and Silicon Valley (where in the US it is known as Creative Labs). The principal activities of the compa ...
took the opportunity to include a game port on the card, producing an all-in-one gaming solution. At the same time, they re-purposed two otherwise redundant pins on the port, 12 and 15, to produce a
serial bus
In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are ...
with enough performance to drive an external
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
port adapter. Previous MIDI systems like the
MPU-401
The MPU-401, where ''MPU'' stands for MIDI Processing Unit, is an important but now obsolete interface for connecting MIDI-equipped electronic music hardware to personal computers. It was designed by Roland Corporation, which also co-authored the ...
used their own separate expansion cards and a complex external adapter, whereas the Sound Blaster only required an inexpensive adapter to produce the same result. By the end of the year the Sound Blaster was the best selling expansion card on the PC, and the game port was receiving widespread software support.
With the exception of laptops—for which companies released joystick adapters for parallel or serial ports, which needed custom software drivers
—through the early 1990s, the game port was universally supported on sound cards,
and increasingly became built-in features as motherboards added sound support of their own. This remained true through the second half of the 1990s, by which time integrated sound support had displaced the third-party sound card to a large degree. By the early 2000s, such support was so widespread that newer sound cards began to dispense with the game port as it was certain the machine they would be used in already had such support, including MIDI. Every Sound Blaster card from the first model up to August 2001 included a game port. In 2001 the Sound Blaster Audigy moved the game port to a second expansion slot, which connected to a header on the card.
The introduction of the first USB standard in 1996, was aimed squarely at the sort of roles provided by the game port, but initially had little market impact. The introduction of the
iMac
iMac is a family of all-in-one Mac desktop computers designed and built by Apple Inc. It has been the primary part of Apple's consumer desktop offerings since its debut in August 1998, and has evolved through seven distinct forms.
In it ...
, which was based almost entirely on USB expansion, began a rapid expansion of USB in the market. This led both to new gaming devices using USB, as well as the profusion of adapters. For instance, the 1997
Microsoft Precision Pro joystick was re-introduced in a version that used a game port connector, but also included a USB adapter in the box.
The rapid takeover of USB meant that this was superfluous when the Precision Pro 2 was released the next year in 1998. By 2000, game ports were purely for backward compatibility with now outdated devices.
Microsoft Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...
discontinued support for the game port with
Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...
, though USB converters can serve as a workaround.
Hardware
The game port's
DA-15
The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.
Description, no ...
connector includes inputs for a total of four analog channels and four buttons. These were almost always implemented as two joysticks with two buttons each, but it is also possible to support four
paddle controllers each with one button, or a single gamepad with two analog sticks and four buttons using the same inputs. The port includes redundant pins, including a total of four +5 V supplies, and separate grounds for most of the buttons. In most similar game ports, like those on the Atari, a single +5 V and ground is used for all the channels.
The game port was originally mounted on a dedicated
ISA
Isa or ISA may refer to:
Places
* Isa, Amur Oblast, Russia
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* Isa, Nigeria
* Isa District, Kagoshima, former district in Japan
* Isa Town, middle class town located in Bahrain
* Mount Isa, Queensland, Australia
* Mount Is ...
card. Since the early 1990s, when the game port moved from dedicated expansion cards to PC
I/O or
sound card
A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio i ...
s, these connectors have usually doubled as connectors for
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
instruments; two of the redundant +5 V and GND pins of the original standard were rededicated to MIDI input and output to make this possible. To use a game port with MIDI instruments, a break-out cable with the necessary opto-isolation hardware and compatible connectors is required - typically these consisted of a male and a female DA-15 and two male 5-pin
DIN connector
The DIN connector is an electrical connector that was standardized by the ' (DIN), the German Institute for Standards, in the early 1970s. The male DIN connectors (plugs) feature a 13.2 mm diameter metal shield with a notch that limits the ...
s. For many sound cards, the game port midi capabilities were based around the Roland
MPU-401
The MPU-401, where ''MPU'' stands for MIDI Processing Unit, is an important but now obsolete interface for connecting MIDI-equipped electronic music hardware to personal computers. It was designed by Roland Corporation, which also co-authored the ...
MIDI interface (in UART mode only), however some older sound cards (notably the original Sound Blaster and Sound Blaster Pro) used a proprietary interface that was not compatible with the MPU-401.
The analog channels are read by sending voltage into the line, through a
potentiometer
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
The measuring instrume ...
in the controller, in this case 100,000 ohm, and then into a capacitor. The value is read by timing how long it took for the voltage in the capacitor to cross a certain threshold. The rate varied depending on the resistance, and thus physical position, of the potentiometer. In the Atari port, which had similar analog channels, there is a convenient timer available in the form of the video clock circuitry. In the PC there is no similar clock because video functionality is normally provided on an expansion card. Instead, a software routine needs to first trigger capacitor discharge by issuing an IO write to the Gameport, and then measure the time it takes to charge them again by constantly polling Gameport. Using original IBM formula, Time = 24.2 μs + 0.011 (r) μs and assuming 100Kohm potentiometers this process can take up to 1.1ms per readout, or over 60ms if we decide to read joystick position 60 times a second. This significant overhead was the reason why using original Gameport on the PC could consume up to 10% of CPU time independent of CPU speed.
Software
Initially there was no standardized software for running the joysticks; applications would poll the known ports associated with the sticks as part of their game loop. This did, however, leave the implementation of a lot of housekeeping tasks to every application that used them, such as looking for and enumerating the active devices, and calibrating them. This changed in
Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturin ...
, which introduced standardized
Windows registry
The Windows Registry is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry. The kernel, device drivers, services, Security Accounts Manager, and use ...
entries to hold these values and make it easier for applications to find these devices.
DirectX
Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with "Direct", ...
further expanded the options through DirectInput with the "joystick mini-driver" with a number of new capabilities. Among these were support for up to six analog axes, a point-of-view hat, and up to 64 buttons. It also supported up to 16 such devices, which could be connected using any interface, not just the game port.
See also
*
USB Human Interface Device class
In computing, the USB human interface device class (USB HID class) is a part of the USB specification for computer peripherals: it specifies a device class (a type of computer hardware) for human interface devices such as keyboards, mice, game con ...
References
External links
{{Commons category
Fairly detailed game port pinouts and specs
Computer connectors
Electrical connectors
Legacy hardware
Game controllers