PS/2 / USB discussion (split from What's the state of play with serial port support?)

[Andre]

5 hours ago, Lorin Millsap said:

NMI is reserved for PS/2.

PS/2 ????? Do you have so many junk old keyboards lying around? I've thrown away all my PS/2 already, as it's too young for 8-bit and to old for modern PCs.... Instead I taught my Commodores to use USB keyboards ?

[Yuki]

34 minutes ago, Andre said:

PS/2 ????? Do you have so many junk old keyboards lying around? I've thrown away all my PS/2 already, as it's too young for 8-bit and to old for modern PCs.... Instead I taught my Commodores to use USB keyboards ?

I guess it's because it's way easier to implement PS/2 rather than USB, PS/2 is probably as simple as a joystick port while, uh, have you seen the size of the USB spec?

[Andre]

1 minute ago, Juju said:

I guess it's because it's way easier to implement PS/2 rather than USB, PS/2 is probably as simple as a joystick port while, uh, have you seen the size of the USB spec?

yes I have. That's the back side indeed. (but if you want to have a look how it could work, look at my 6502 USB driver linked above, via the PET userport SPI)

[StephenHorn]

As I recall, the reasoning for not supporting USB was two-fold. First, it was viewed as more complicated to support in the kernal than PS/2, second it was more expensive to add to the BOM than PS/2.

[SlithyMatt]

And remember, these exist and cost about $2: 

[lamb-duh]

29 minutes ago, SlithyMatt said:

And remember, these exist and cost about $2:

Do those work with any usb keyboard or mouse? I thought they were just a convertor between two connector types and relied on the mice/keyboard supporting both ps/2 and usb.

[TomXP411]

34 minutes ago, SlithyMatt said:

And remember, these exist and cost about $2: 

Those only work if your keyboard is actually a PS/2 keyboard.... modern keyboards have pretty much dropped the dual protocol implementation and only support the USB protocol now. 

In fact, if you buy the WASD keyboard, you have to request the older firmware, because the latest firmware no longer has PS/2 support. 

[StephenHorn]

8 minutes ago, lamb-duh said:

Do those work with any usb keyboard or mouse? I thought they were just a convertor between two connector types and relied on the mice/keyboard supporting both ps/2 and usb.

It's true that these style of adapters will not work on more modern keyboards, which have stopped including the dual-mode controller IC which enabled keyboards to operate on a passive PS/2 adapter.

1. 
   Keyboards with the dual-mode controller IC are not that terribly old, you might have one lying around, but the only way to know for certain is to risk the $2 USD on Amazon and try it.
   


2. 
   Failing that, premium keyboard vendors specifically ship keyboards with PS/2 compatibility. See also, the premium WASD keyboard roughly half and again of too many people seemed to believe was a recommended purchase separate from the X16, until the store link was removed.
   


3. 
   If you want to buy a bespoke keyboard but don't want to shell for the good stuff, there's always eBay.
   


4. 
   If you're simply concerned about whether you'll have a keyboard at all, do remember that the X16 will ship with a PS/2 keyboard.
   

Before we get too off-track with the tangent about keyboards, I want to re-emphasize that the team has said the X16 will ship with a basic PS/2 keyboard.

[Lorin Millsap]

Please keep this thread on topic. We are discussing RS232 serial, not PS/2.


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[Yuki]

What Lorin said. There could be another thread about PS/2. Edit: done