Digital Joysticks

Technical

The CPC joystick port is (more or less) based on the Atari-standard, for details on the pin-outs (and differences between Amstrad CPC and normal Atari/Commodore ports), see:

• CPC Joystick Port Pin-Outs

At software side, the joystick port is part of the keyboard matrix, accessed via the general purpose I/O port in the PSG chip, which is itself accessed indirectly via the 8255 chip.

Official Amstrad Joysticks

• Amstrad JY-1/JY-2 joysticks

Amstrad's two-button joysticks. The quality isn't spectacular, so most CPC users tended to use third-party sticks, with only 1-button, but better quality. The JY-2 version contains a connector for a second joystick (equivalent to a built-in Y-cable).

Official CPC+/GX4000 Joypads

The CPC+ and GX4000 were shipped with one or two digital joypads included. Technically, they work same as normal joysticks. But, they have two buttons. And, the GX4000 doesn't have a keyboard which could be used instead of a second fire button. In result, some CPC+/GX4000 games may rely on 2-button hardware, making them incompatible with regular 1-button joysticks.

Compatible Standard Joysticks

All Atari-compatible digital joysticks with Single Fire Button and Four Direction switches should be usually working with the CPC. For example, classic Competition Pro joysticks or the Konix Speedking.

Incompatible Standard Joysticks

• Joysticks that do require 5V/GND supply (eg. for built-in auto-fire circuits) won't work on the CPC.
• Joysticks with 2-3 buttons may also be problematic (in the Atari standard, 2nd/3rd button are wired between POT0/POT1 and 5V).
• And, in lack of the POT inputs, any kind of analog devices (like Atari paddles) won't work on the CPC.
• Newer joysticks with PC-style 15pin or USB connector obviously won't fit to the CPCs 9pin port (unless one eliminates the electronics inside of those joysticks, and re-wires their botton/dirction switches directly to the CPCs joystick port).

Y-Cable

The original CPC models have only one joystick port, but can be used with 2 joysticks when using a Y-cable:

• Joystick Y-cables

The CPC+/GX4000 have two digital joystick ports (which work equivalent to an incompletely implemented Y-cable with only 8 diodes - there are no diodes in the fire button lines, so fire buttons do not work properly with two players).

Joystick Related stuff... Sega Controllers...

• Digital Joystick Related

Developing programs that use joystick

In the CPC world it is more common that a game supports both digital joystick and keyboard for those users who don't own joysticks.

There are some common keyboard configurations used:

• Cursor keys & SPACE
  • This configuration is often used and is great for the CPC6128 and Plus and playing using emulators.
  • This is not good for CPC 464 and 664 (which have uncomfortably arranged cursor keys)

• Q,A,O,P,SPACE - (Q up, A down, O left, P right, SPACE fire)
  • This is a good solution, and it's a sort of standard (used by many games).
  • Note: On french keyboards it'd be A,Q,O,P - anyways, the "UP" key is always Row8.Bit3, no matter if it's locally called "Q" (english QWERTY keyboard), or "A" (french AZERTY keyboard).

Best would be to support joysticks, plus the above two keyboard mappings. Best to support them all at once (without needing the user select which one to use). In addition, it is also nice if the keys could be redefined but that is not necessary.

Relevant locations in Keyboard Matrix

Direction	Joystick 1	Joystick 2	Cursor,Space	Q,A,O,P,Space
Up	Row9.Bit0	Row6.Bit0 (6)	Row0.Bit0	Row8.Bit3 (Q)
Down	Row9.Bit1	Row6.Bit1 (5)	Row0.Bit2	Row8.Bit5 (A)
Left	Row9.Bit2	Row6.Bit2 (R)	Row1.Bit0	Row4.Bit2 (O)
Right	Row9.Bit3	Row6.Bit3 (T)	Row0.Bit1	Row3.Bit3 (P)
Fire1	Row9.Bit4	Row6.Bit4 (G)	Row5.Bit7	Row5.Bit7 (Space)
Fire2 (*)	Row9.Bit5	Row6.Bit5 (F)	(wherever)	(wherever)
Fire3 (**)	Row9.Bit6	Row6.Bit6 (B)	(wherever)	(wherever)

(*) Most CPC joysticks only support 1 fire button. When using Fire2 or Fire3, also provide an alternate key on the keyboard.

(**) Fire3 is only supported on CPC hardware, not on Amstrad Plus and GX4000 hardware.

Other game controller inputs

The CPC+/GX4000 additionaly have an 15pin Analog Joystick Port, and a 6pin Lightgun socket (AUX).

Other hardware that can be connected to the CPC joystick port

The CPCs digital joystick port is occasionally also misused to connect other hardware, known examples are: Some Lightguns: (Gunstick, West Phaser). Amstrad's Lightpen (Amstrad LP-1 light pen). A rather crappy 8bit printer port extension (CPCI 8bit Printer Mod). And, various mouse interfaces (AMX Mouse, Atari-ST mouse adapter, Dk'tronics Mouse Interface, CPC-Mousepack 2.0, GEOS mouse). Plus exotic things like the Ambug Robot and Codemasters CD.

On the original CPCs, the direction/button inputs can be reprogrammed as outputs (via PSG/PPI config). However, this will NOT work on the CPC+/GX4000's dual joystick ports - which include diodes (like normal joystick Y-cables).