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N-key rollover USB question
posted in Hardware
1
#1
0 Frags +

I have a cm storm quickfire which is supposed to support N-key rollover, but I was reading up on it and apparently the USB connector only supports up to 6 key rollover. How do i get the full N-Key rollover instead of 6 key?
There's a little switch meant for switching between the two on the keyboard itself (as well as in the manual), so I figure there should be some way.

edit: friend told me I could buy a ps2 adapter, but would that work even if the keyboard doesnt have a ps2 out? idk

I have a cm storm quickfire which is supposed to support N-key rollover, but I was reading up on it and apparently the USB connector only supports up to 6 key rollover. How do i get the full N-Key rollover instead of 6 key?
There's a little switch meant for switching between the two on the keyboard itself (as well as in the manual), so I figure there should be some way.

edit: friend told me I could buy a ps2 adapter, but would that work even if the keyboard doesnt have a ps2 out? idk
2
#2
0 Frags +

Mine (quickfire rapid) came with a ps2 adapter. If you lost it or something you can just buy one, it doesn't have anything special.

Mine (quickfire rapid) came with a ps2 adapter. If you lost it or something you can just buy one, it doesn't have anything special.
3
#3
-5 Frags +

in what situation are you going to be pressing 6 keys simultaneously?

6-key rollover is highly practical, and you really don't need higher...

think about it, 3 of your 5 fingers on each hand pressing keys all together, at the same time

tbh i would be impressed if you actually do surpass the rollover while playing tf2

in what situation are you going to be pressing 6 keys simultaneously?

6-key rollover is highly practical, and you really don't need higher...

think about it, 3 of your 5 fingers on each hand pressing keys all together, at the same time

tbh i would be impressed if you actually do surpass the rollover while playing tf2
4
#4
1 Frags +

it is pointless but im a gear whore and have ocd
guess ill buy an adapter thanks trog

it is pointless but im a gear whore and have ocd
guess ill buy an adapter thanks trog
5
#5
0 Frags +

a PS2 adapter should be like 1$

a PS2 adapter should be like 1$
6
#6
-7 Frags +

It's a driver thing.

It's a driver thing.
7
#7
-5 Frags +

ps2 over usb can be incompatible with some bios and cause your pc to crash and soft reboot its a common problem with keyboards like the quickfire tk

ps2 over usb can be incompatible with some bios and cause your pc to crash and soft reboot its a common problem with keyboards like the quickfire tk
8
#8
5 Frags +

#1
PS/2 is the only way* to get N-KRO. Like #2 the CM Storm Quickfire should have a PS/2 adapter included (mine did too). If you can't find it just buy one.

*there are strange and complicated ways to get N-KRO but they are only suited for connecting a N-KRO cabable keyboard with PS/2 or another N-KRO cabable connector to USB with an active adapter or a teensy to keep the N-KRO on USB. Unless your motherboard doesn't have a PS/2 port there's no reason to go with this complicated and more expensive method.

#6
No. Although you can do stuff with drivers to get more than 6-KRO, you can get for example 12-KRO by pretending that you connected a hub with 2 keyboards, or you can use a on-board controller within the keyboard (I've seen 64-KRO over USB).

None of these are N-KRO however. The difference is negligible because most people are limited to 10 (give or take a few) keypresses by their number of fingers anyway.

The main difference is that USB uses polling which adds a delay (<=1 ms for USB 2.0, less for USB 3.0 but there are no keyboards that use it yet) and the limit to 6-KRO** whereas PS/2 uses near instantaneous interrupts*** with true N-KRO (unlimited! keypresses).

**Although it can be circumvented (see above) this will add further delay, depending on the implementation either always or just when more than 6 keys are pressed.

***We're talking about a few CPU clockcycles delay. Definitely below 1µs though, even for the worst case.

EDIT: fixed a(n) mistake

#1
PS/2 is the only way* to get N-KRO. Like #2 the CM Storm Quickfire should have a PS/2 adapter included (mine did too). If you can't find it just buy one.

*there are strange and complicated ways to get N-KRO but they are only suited for connecting a N-KRO cabable keyboard with PS/2 or another N-KRO cabable connector to USB with an active adapter or a teensy to keep the N-KRO on USB. Unless your motherboard doesn't have a PS/2 port there's no reason to go with this complicated and more expensive method.


#6
No. Although you can do stuff with drivers to get more than 6-KRO, you can get for example 12-KRO by pretending that you connected a hub with 2 keyboards, or you can use a on-board controller within the keyboard (I've seen 64-KRO over USB).

None of these are N-KRO however. The difference is negligible because most people are limited to 10 (give or take a few) keypresses by their number of fingers anyway.

The main difference is that USB uses polling which adds a delay (<=1 ms for USB 2.0, less for USB 3.0 but there are no keyboards that use it yet) and the limit to 6-KRO** whereas PS/2 uses near instantaneous interrupts*** with true N-KRO ([b]unlimited![/b] keypresses).

**Although it can be circumvented (see above) this will add further delay, depending on the implementation either always or just when more than 6 keys are pressed.

***We're talking about a few CPU clockcycles delay. Definitely below 1µs though, even for the worst case.

EDIT: fixed a(n) mistake
9
#9
5 Frags +

^ this guy knows what he's talking about.

^ this guy knows what he's talking about.
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