Can a joypad be moded for the MSX?

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By ali6x944

Master (196)

ali6x944's picture

11-06-2019, 15:22

Hi MSXers,
recently, I was learning MSX-basic and Z80 assembly, in addition, I'm looking to develop MSX peripherals or to modify existing non-MSX compatible hardware to make it compatible with MSX hardware...
and in line with that, I was looking at modifying an ATARI 7800 Joypad to work with the MSX which looks rather plausible, the construction is rather simple and straight forward, I was wondering if anybody did before, also can a serial joypad like that of the NES or Famicom be used in any capacity?
really excited to hear what you have Big smile

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By Meits

Scribe (5651)

Meits's picture

11-06-2019, 16:08

Are Atari 7800 controllers compatible with Atari 2600 controllers? I do remember that in the early 90s I connected an MSX joypad to a 2600 and it just worked. Second button was off limits though.
If there's no autofire involved it's just a matter of pinout conversion which should probably be done on an adapterboard or in an extension cable. So you don't have to "destroy" your joypad.

By gdx

Prophet (3085)

gdx's picture

11-06-2019, 16:32

Ali6x944 wrote:

the construction is rather simple and straight forward

Yes look here: http://wiki.icomp.de/wiki/DB9-Joystick

Ali6x944 wrote:

the construction is rather simple and straight forward, I was wondering if anybody did before

Many people have already done it.

Ali6x944 wrote:

the NES or Famicom be used in any capacity?

Yes but reading data is done bit per bit. You will need to program a specific routine in machine language to use a NES controller.

By Danjovic

Expert (85)

Danjovic's picture

12-06-2019, 04:40

You can read nes controller in basic using a trick
https://hackaday.io/project/27494-snes-gamepad-adapter-for-m...

By ali6x944

Master (196)

ali6x944's picture

12-06-2019, 13:31

gdx wrote:

Yes but reading data is done bit per bit. You will need to program a specific routine in machine language to use a NES controller.

could it be done in MSX1 machines, in assembly?

gdx wrote:

Many people have already done it.

can you share a link with us?
---------------------------------------------------------------------------------------------------------------------------------------------------------
http://www.the-liberator.net/site-files/retro-games/hardware...
do I need to short the resistors on the trig1 and trig2 buttons?

Meits wrote:

Are Atari 7800 controllers compatible with Atari 2600 controllers? I do remember that in the early 90s I connected an MSX joypad to a 2600 and it just worked. Second button was off limits though.
If there's no autofire involved it's just a matter of pinout conversion which should probably be done on an adapter board or in an extension cable. So you don't have to "destroy" your joypad.

for me, I would like to permanently mod it, however looking at this form a collector point of view I can see the appeal for an adapter, and for compatibility:

WIKI wrote:

The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console officially released by the Atari Corporation in 1986.[3] It is almost fully backward-compatible with the Atari 2600, the first console to have backward compatibility without the use of additional modules. It was considered affordable at a price of US$140 (equivalent to $320 in 2018).

By NYYRIKKI

Enlighted (5399)

NYYRIKKI's picture

13-06-2019, 01:40

ali6x944 wrote:

do I need to short the resistors on the trig1 and trig2 buttons?

Do not... That will cause a short circuit...

Looking at the pics, I would say...

Before mod (BL034):
1 - Orange
2 - Yellow
3 - Red
4 - White

After mod:
1 - White
2 - Orange
3 - Joy Pin 7 (or N/C)
4 - N/C

Loose wires:
Yellow (GND)
Red (+5v)

By Danjovic

Expert (85)

Danjovic's picture

13-06-2019, 03:28

The straightforward solution is to invert the signals from the buttons and that can be accomplished by a pair of NPN transistors.

Please check : https://hackaday.io/page/6326-atari-7800-joypad-to-msx-adapter

By gdx

Prophet (3085)

gdx's picture

13-06-2019, 11:29

According to the table in the link I gave above, to modify your Atari 7800 Joypad you must change the cable because there is no wire going to pin 4 (button 2).

You can use this cable by cutting the useless connector:
https://www.ebay.com/itm/New-Controller-extension-cable-for-...

Then connect wires like this:

By ali6x944

Master (196)

ali6x944's picture

14-06-2019, 21:59

so far thanks to @Danjovic, @gdx, and @NYYRIKKI, we found a good number of permanent and code based ways to read or modify these joysticks:
@NYYRIKKI generic genesis joypad mod:
https://www.msx.org/wiki/How_to_get_joypad_very_cheap_for_MSX
@Danjovic Atari 7800 joypad to MSX Adapter:
https://hackaday.io/page/6326-atari-7800-joypad-to-msx-adapter
@Danjovic (S)NES gamepad adapter for MSX computers:
https://hackaday.io/project/27494-snes-gamepad-adapter-for-m...
@gdx great and thorough step-by-step method to -permanently modify- Atari 7800 joypad to MSX:
HERE :) :D

so we did:
1.snes joypad /possibly even famicom I joypad?? -in software-
2.atari 7800 joypad -in hardware-
3.genesis joypad -in hardware-
is there any other easy to hack joysticks to aim for?

By Grauw

Ascended (8515)

Grauw's picture

14-06-2019, 23:33

The Genesis joypad is pretty similar to MSX, and the mod also makes all 6 buttons available, so that’s pretty nice.

By gdx

Prophet (3085)

gdx's picture

15-06-2019, 14:45

Some info for two great solutions here:
- Sega Genesis adapter
- SNES controller/mouse adapter

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