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geekhack Community => Keyboards => Topic started by: CyberShadow on Wed, 07 July 2010, 21:38:42

Title: Hardware character repeat rate
Post by: CyberShadow on Wed, 07 July 2010, 21:38:42

Hi, first post here. :)

I've been wondering what keyboards support using character repeat rates above 30 CPS. I'm currently using a software hack that gets me 60 CPS (which is the software limit), which was an amazing change but has some problems in certain applications. I'm also considering getting a better keyboard, so being able to up the character repeat rate would be a plus for me. I know that Avant and Northgate keyboards have this (up to 125/120 CPS), but their actuation force seems to be a bit too high for prolonged comfortable typing.
(http://thecybershadow.net/track.gif)

Title: Hardware character repeat rate
Post by: didjamatic on Thu, 08 July 2010, 00:57:25

I don't recall the range but Northgate Omnikeys are programmable.  Check out their manual here (http://www.lueckdatasystems.com/Northgate_OmniKey_Keyboards).

Welcome to Geekhack.

Title: Hardware character repeat rate
Post by: CyberShadow on Sat, 17 July 2010, 05:53:03

Hmm... thanks. Looks like this feature is as rare as I thought.

I just looked at the PS/2 keyboard protocol (http://www.computer-engineering.org/ps2keyboard/) and it looks like the repeat rate is handled by the keyboard encoder (I had previously thought that was the job of the controller, which is on the PC motherboard), and the way the protocol is designed there's even no way to send a repeat rate beyond the normally-settable one. (You can get around this limitation with software, but Windows' implementation has issues as stated above.)

I wonder, how hard would it be to create a repeat-rate adapter (using e.g. DYI electronics kits)? It would need to store the current scancode and resend it on a timer... This sounds like a really fun project, though I'm a programmer and don't know much about electronics :P

Edit: this is relevant to my interests: http://www.keelog.com/diy.html

Title: Hardware character repeat rate
Post by: slam on Tue, 20 July 2010, 00:15:18

Switch to linux :)  my repeat rate is currently set at 83cps .. max I believe is 255.  It's handled in software and I've never had a problem with it (I like fast repeat rates, it drives me nuts when I have to use a slow repeat rate)

Title: Hardware character repeat rate
Post by: noctua on Tue, 20 July 2010, 04:07:01

Specially for USB keyboards: The "Repeat Rate" and "Delay Before First Repeat" are
implemented by the host and not in the keyboard (this means the BIOS in legacy mode).
The host may use the device report rate and the number of reports to determine how
long a key is being held down. Alternatively, the host may use its own clock or the
  idle request for the timing of these features. (Appendix C - USB Keyboard Implementation)

Title: Hardware character repeat rate
Post by: CyberShadow on Tue, 20 July 2010, 04:09:07

Thanks, I've stumbled upon that as well. I'm looking at the idea of writing a keyboard filter driver to boost the repeat rate.