Editing Atari interface (section)

==Keypads==
===Atari 2600 keypads===
Atari released several keypads for the Atari 2600 that all worked the same way.
They were supported by some Atari's 8-bit computer software as numeric keypads, albeit using telephone layout (1,2,3 at top, * and # keys) instead of calculator layout (1,2,3 at bottom and decimal point). All use calculator-style buttons.

The switches are exposed as a 3×4 [[Keyboard matrix|matrix]] using the direction, trigger and pot lines. This worked on Atari machines because some pins could be configured as output in software.<ref name="atari400hwm1">[http://www.atarimania.com/documents/atari-400-800-hardware-manual.pdf Atari 400/800 Hardware Manual], Dated 1982. Retrieved from [www.atarimania.com AtariMania] on 2018-04-24</ref>

* The CX21 ''Keyboard Controller'' has the digits, and * and # symbols printed on a label. They were sold in pairs and can be slotted together.
* The ''Basic Programming'' controllers were a pair sold with a very primitive BASIC programming cartridge. The hardware is the same as the Keyboard Controllers but with different printed labels. The program uses four layers that are toggled between by pressing a button on the left controller.
* The ''Video Touch Pad'' uses a paper overlay over unlabelled rectangular buttons. Different paper overlays were supposed to be distributed with different games, but only one game is known. 
* The ''Kid's Controller'' (for games from the Children's Television Workshop) uses larger circular, numbered buttons and different larger overlays than the Video Touch Pad.

The idea of having a numeric keypad with overlays was reused later for the Atari Jaguar gamepad.

===Atari CX85 Numerical Keypad===
The ''Atari CX85 Numerical Keypad'' has 17 proper keys in a calculator layout and a different protocol from Atari 2600 keypads.
Instead of exposing a matrix, it produces a [[scancode]] on the direction and pot lines.
<ref>http://www.atarimania.com/documents/Atari_CX85_Numerical_Keypad_Technical_Reference_Notes.pdf Atari CX85 Numerical Keypad Technical References Notes]. Retrieved from [www.atarimania.com AtariMania]</ref>

===Cardco Cardkey===
The Cardkey is a 16-key keyboard that produces a scancode + "button" press. The C64 driver also supports the CX85. The scancodes for the numeric keys are the values printed on those keys. Each key is set up only with diodes to the input lines which means that there is only 1-key [[rollover]] and two keys at once would produce the wrong scancode.<ref>Post by '''buzbard''' in the lemon64.com forum—[http://www.lemon64.com/forum/viewtopic.php?p=530434#530434 Numerical keypad from Commmodore calculator?] on 2012-09-12. Retrived 2018-06-11</ref>

===Rushware keypad===
Produces the same scancodes as Cardco Cardkey but activates differently.<ref>C64 Wiki—[https://www.c64-wiki.com/wiki/Rushware_keypad Rushware keypad]. Last edited 2016-12-05. Retrieved 2018-06-12</ref>

===Coplin keypad===
Nicholas Coplin has designed and published free schematics for a numeric keypad as well as a driver for the Commodore 64. Keys produce the same codes as corresponding joystick directions, allowing the keypad to be used as cursor keys in programs that were made for joysticks. This includes also diagonals, so e.g. key 8 + key 4 = key 7.
Keys 0 and 5 produce opposing directions at once and Enter is wired to Fire. 
<ref>64HDD—[http://www.64hdd.com/projects/c64-proj3.html#keypad Numeric Keypad] by Nicholas Coplin.</ref>

===ColecoVision controllers===
The ColecoVision games console and Coleco Adam computer supported Atari joysticks (without autofire) but came with extended controllers that had not only a joystick but two buttons and a 3×4 numeric keypad all in one.
Instead of one ground line they had two strobe lines: the pin 8 for the Joystick in Atari-compatible fashion, and pin 5 activating the second button and keypad providing a [[scancode]] instead of a direction.

The ''Super Action Controller'' has also two additional buttons wired as part of the keypad and a horizontal [[spinner]] producing a quadrature code.<ref name="">Programming Ponderings—[http://mheironimus.blogspot.se/2015/12/ultimate-classic-game-console-joystick.html Ultimate Classic Game Console Joystick to USB Adapter]. Dated 2015-12-28. Retrieved 2018-04-24</ref>