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18 KiB

Electronics Stuff

C Stuff

For the AVR

Protocol Stuff



Other People's Code

Keyboard Firmware

USB Libraries

TWI Libraries


Hardware Documentation


Keyboard Testing Tools

Typical Keyboard Information

  • [Keyboard Scan Rates] ( list (on
    Keyboards seem to typically scan at rates from a little below 100Hz to about 300Hz, with the most common values a little below 100Hz. The [PJRC usb_keyboard] ( example documentation has a limit of 1000 packets (so 500 presses -> releases) per second, but says that even that speed might overwhelm host software, which expects keystrokes to come much more slowly. And, a debounce time of 5ms (which is the spec'ed high value for Cherry MX switches) would give us a max scan rate of 200Hz.

Other Awesome Keyboard Projects

Documentation and Design Tools

Copyright © 2012 Ben Blazak
Released under The MIT License (MIT) (see "")
Project located at