Amiga : Connect a PS/2 mouse (PC model) to your Amiga / Atari

PS/2 Mouse Adapter for your Amiga / Atari

Both for the Commodore Amiga and the Atari ST Family it is increasingly difficult to find a working mouse  (After this I only mention Amiga, but where I write Amiga you can just read Atari ST family).

There are many mice that have died mechanically, that start to falter more and more and no longer react to the mouse buttons (usually due to dirt and dust on the mechanisms), these often ended up in the trash can.
years later, the amiga comes out of the attic again and it turns out that there are no more mice, in short, more Amiga's than mice and so a solution had to be found.

The mice for these machines are different from the PC variants of the mouse, although the very first PC mice did have a DB-9 plug, they were totally incompatible with the mice used for the retro computers we cherish.
The protocols that PC mice use are different and therefore even though the plug fits technically, signals and protocols do not correspond at all to what the Amiga expects.

The solution came in the form of a small interface with on one side a DB-9 that goes into the Amiga and the other side has a PS/2 connection (Or a USB, but more about that later)

The heart of this interface is a PIC microcontroller, this PIC takes care of the protocol conversion.
it receives the data packets from the PS/2 mouse, interprets them, converts them to a standard Amiga H, HQ, V, VQ motion information and the status of three mouse buttons and sends them to the Amiga mouse port.
It does not support 4th and 5th button, nor additional scroll wheels found on some luxury PC mice. Such mice will be recognized and used as standard PS/2 mouse with only standard movement and two or three buttons.

The interface is available in 2 flavors : with a PS/2 connection, and with a USB connection, but that does not mean that a USB mouse works on this adapter.
On the contrary, the protocols used by a USB mouse are not supported by this adapter.

Why a USB version you wonder, well simple : in the transition period from PS/2 connections to USB connections there have been mice on the market for a long time that output both protocols.
With such a green adapter you connect such a USB mouse to a PS/2 port, so those mice worked on both one and the other port.
So please note: Not all mice support that PS/2 protocol yet.

There are still plenty of PS/2 compatible mice for sale (mouse with green PS/2 plug is guaranteed PS/2 compatible :), a mouse with a USB plug you really have to find out if PS/2 is still supported.
If you want to try it with an old USB mouse of your own, then you most likely have an HP / Dell / Microsoft / Logitech mouse from around the turn of the century.
Newer models are also possible, but the younger the mouse is, the greater the chance that the mouse no longer has a PS/2 protocol on board and therefore does not work.

In order not to have a USB mouse via a USB to PS/2 Adapter in a PS/2 to Amiga interface in the back of your amiga, there is a version with a USB port that removes the USB to PS/2 adapter in between.

(Atari XL, MSX, Commodore 64 and a lot of other systems also have a DB-9 port, but are not compatible with this solution)

In summary , why a PS/2 to Amiga DB-9 mouse Adapter :

Works with all PS / 2 optical and ball mice.
No more fluffing your old Amiga and Atari mice.
Ergonomically more responsible models than, for example, the Amiga Tank mouse.
Works with the Amiga Pre-Boot menus.
Ultra-smooth and sensitive mouse pointer.
Your system is not aware of a different type of mouse, so 100% compatible !!
Can be configured for both Amiga and Atari ST by converting 2 jumpers.

Note: The DB-9 connector of the interface is made of metal, so it is recommended to connect it only when the machine is turned off, just to make sure you don't accidentally close it.

Note : Although I haven't come across it yet it could theoretically be possible that there is a PS/2 mouse that is not supported, so far I haven't experienced this yet, but you'll be the first 🙂
if it happens to you , test with another mouse first and pass it on to me , then I'll list it as unsupported model.