Editing Atari interface (section)

===Amstrad===
The [[Amstrad]] CPC computers has one or two "User ports" for two-button Amstrad joysticks.
Amstrad PC-1512<ref name="amstradpc1512"/> and PC-1640<ref name="amstradpc1640"/> had a single Amstrad "Joystick" port on the keyboard.
The joystick port/s are actually part of the computer's [[keyboard matrix]] and are strobed by the keyboard controller.

Many games used Button 2 as primary fire, so they supported Atari-standard one-button joysticks. If Button 1 was needed, its function was often also on a keyboard key.
The opposite however: using an Amstrad joystick in a Atari-compliant port (such as the Amstrad/Sinclair PC [[#PC bus mouse|mouse port]]) could damage the system because pressing Button 1 would short the +5V line to Ground.

The CPC supported up to two joysticks on the same port, using pass-through or an adaptor using diodes to avoid [[ghosting]].
The first joystick had its ground line strobed on pin 8, and the second on pin 9 — each being a separate column in the keyboard matrix.

CPC+/GX4000 had two ports through wiring ''almost'' like such an adaptor except that diodes were missing for the fire buttons, thus introducing conflicts between joysticks. The two-port machines also lacked the "spare" line and were incompatible with some older peripherals, especially those that had been using pins as outputs.
<ref name="cpcwiki">CPCWiki — [http://www.cpcwiki.eu/index.php/Connector:Digital_joystick Connector:Digital joystick]. Dated 2013-02-08. Retrieved 2018-05-24</ref>

Amstrad PC's did not support a second joystick, and Sinclair PC-200 had an IBM-compatible [[Game port]] instead<ref name="sinclairpc200"/>.