ps2 converter for mechanical keyboard for nkey rollover?

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Limp Gawd
Joined
Dec 26, 2009
Messages
218
Hey I have an old Filco Ninja Majetictouch 2 that I bought in 2012.

Was wondering do you guys know if I can just plug it into the USB and the nkey rollover will work, or do I need to put on a ps2 converter onto the end of the USB and plug it into my mobo's ps2 slot for nkey to work??
 

KD5ZXG

Gawd
Joined
Mar 24, 2017
Messages
703
There is nothing to be found inside those PS/2 converters, all the magic (or not) is in the keyboard.
Most USB keyboards retain fallback capability to PS/2 over USB, just so those converters can work.

I've searched high and low for a PS/2 keyboard in good condition to connect with Pi Pico's GPIO.
Most were thrown away long ago or drowned in crumbs and coffee. Turns out USB keyboards are
a fine replacement, don't be fooled by the shape of the USB connector isn't round. Some even work
at 3.3V which allows to omit a logic level converter. 5V logic level is normal, not an issue for PCs.

PS/2 over USB
pin1 = +5V
pin2 = Data
pin3 = Clock
pin4 = Ground

Even futher back, PS/2 was purposely adaptable to original XT 5pin DIN. Signals did not change.
http://www.burtonsys.com/ps2_chapweske.htm

No reason to expect an older XT or PS/2 keyboard to talk USB. Converting the other way would
take more than wires. A smart adaptor of some sort...

Would think rollover has to be a feature of the keyboard before data is serialized to PS/2 or USB?
If rollover was only in the PC's BIOS (to care which port was used) wouldn't be nearly as effective.
Thats an "I think", not an "I know". I think I know all sorts of things I frequently don't.

MadeAThing.jpg

Center four pins of formerly USB3 thing on the left dumbed down to accept PS/2 over USB.
Outboard pins connected to the shield for strength.
 
Last edited:

OFaceSIG

2[H]4U
Joined
Aug 31, 2009
Messages
3,319
I was going to say. The limitation is usually USB when it comes to nkey rollover. I've always read that USB simply can't do it. So if the original connection is USB, you're SOL. I bought a newegg/rosewill rk-6000 in 2011 that I still use today because PS/2 was an option out of the box.
 

auntjemima

[H]ard DCOTM x2
Joined
Mar 1, 2014
Messages
9,953
There is nothing to be found inside those PS/2 converters, all the magic (or not) is in the keyboard.
Most USB keyboards retain fallback capability to PS/2 over USB, just so those converters can work.

I've searched high and low for a PS/2 keyboard in good condition to connect with Pi Pico's GPIO.
Most were thrown away long ago or drowned in crumbs and coffee. Turns out USB keyboards are
a fine replacement, don't be fooled by the shape of the USB connector isn't round. Some even work
at 3.3V which allows to omit a logic level converter. 5V logic level is normal, not an issue for PCs.

PS/2 over USB
pin1 = +5V
pin2 = Data
pin3 = Clock
pin4 = Ground

Even futher back, PS/2 was purposely adaptable to original XT 5pin DIN. Signals did not change.
http://www.burtonsys.com/ps2_chapweske.htm

No reason to expect an older XT or PS/2 keyboard to talk USB. Converting the other way would
take more than wires. A smart adaptor of some sort...

Would think rollover has to be a feature of the keyboard before data is serialized to PS/2 or USB?
If rollover was only in the PC's BIOS (to care which port was used) wouldn't be nearly as effective.
Thats an "I think", not an "I know". I think I know all sorts of things I frequently don't.

View attachment 440585

Center four pins of formerly USB3 thing on the left dumbed down to accept PS/2 over USB.
Outboard pins connected to the shield for strength.
I have some PS2 keyboards. If that's your deal and you want to pay shipping lol

Edit: but, to save you time and money, I would hit up a thrift store.
 

jthomas

Limp Gawd
Joined
Jan 4, 2006
Messages
252
USB can do NKRO just fine if the manufacturer chooses to. Nerdy explanation.
In the case of your Majestouch, Filco didn't choose too. However, it will still do NKRO with the PS/2 adapter.
 

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Limp Gawd
Joined
Dec 26, 2009
Messages
218
The input lag was actually my main concern over NKEY roll over, people say it's not supposed to be a big deal but my OCD thinks otherwise.
 
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