Amstrad CPC joystick with 1,2 or 3 fire buttons usable with Spectrum?

I was not aware that some cpc joysticks (or with a 'cpc mode selector') allowed up to 3 fire buttons!

But it seems the pinout is not the usal one used with atari standard.

I was wondering if a cpc joystick with, say, 2 fire buttons and the plug rewired to match the pins used with the spectrum interface (pin 6 - fire 1; pin 8 - ground; pin 9 - fire 2) could actually work?


  • This is probably no help but I seem to recall using what was a MegaDrive '3 button' (iirc) controller with a Speccy interface years back, and I think one or two of the 'fire' buttons worked the other(s) were dead. I do remember it was easier to play a few games with that 'pad' than a stick however.

    I think the question you have is possibly dependent on the interface/protocol though in if it supports two fire 'inputs' , IF2/Protek/Cursor won't as these are just the 'top row' of keys in effect. I'm not actually sure if Kempson could accept two fire inputs or not.

    Leaving aside the game code allowing for this too I guess.

    I see what you're saying though. :) :) It is a very good point/thought.
  • It is possible to use two ports (say, the two ports of the Interface II/Sinclair Joystick) for up to ten control inputs. It’s important not to short the address lines or the keyboard lines on the ULA with each other, however, so the internal connections of the joystick must be examined and possibly reworked—but it’s certainly possible.
    Every man should plant a tree, build a house, and write a ZX Spectrum game.

    Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
    and zasm Z80 Assembler syntax highlighter.
    Member of the team that discovered, analyzed, and detailed the floating bus behavior on the ZX Spectrum +2A/+3.

    A few Spectrum game fixes.
  • I often use a re-wired Sega Megadrive Joypad that's plugged into a re-wired Sinclair Interface II. All of the buttons work. However. You do need to be handy with a soldering iron to get it all to work.
  • The answer is not simple due to the wide range of joystick interfaces that were made.
    And what it says on the outside of the box does not always help (there were more than three designs of joystick interfaces from Kempston for a start...).

    The second problem is that various electronic circuits were used. Some used the computer 0V/GND/ground as a common. For these where there are either a 8 bit buffer/driver chip or two joystick ports, it is fairly simple to modify the interface or build an external cable adapter. But where this is not the case, it is a lot harder.

    If the interface uses a 6 bit buffer/driver chip and only has one joystick port, it is normally game over, as bit 6 is already in use to provide null values for all the “unused” data bits (bits 5, 6 and 7).

    If there are two joystick ports (like on the Amstrad made +2A, +2B, +3, +3B), any extra fire buttons that you wish to connect to the second port have to be electrically isolated from the functions on the first port. This is because the common connections are multiplexed lines and NOT 0V/GND/ground.

    The Sinclair Interface II and the Amstrad produced +2 (grey) can use both joystick ports together (as they both use a special ULA chip and the joystick common on both is 0V/GND/ground).

    More recent interfaces that are described as Kempston compatible often do support two or three fire buttons.

    Very few (if any) original games will support two fire buttons (unless they are/have been modified) unless they have the option to use redefined keys and you are using a Sinclair interface or equivalent.

  • edited April 2019
    What I use is a rewired megadrive pad (=removed all the electronics inside so that the buttons are just simple switches and 2nd button is pin 5) and ComCon interface.

    This way I can use 2 button joystick with every game. Even with games which do not support any joysticks and/or don’t have redefinable keys.

    Makes playing games like Green Beret (=have to fire special weapon quickly) or Ant Attack (=tricky default keys) A LOT more enjoyable.
    Post edited by arttu on
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