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Where can I find somecircuits about the keyboard connection？ — Parallax Forums

Where can I find somecircuits about the keyboard connection？

daniel dingdaniel ding Posts: 52
edited 2011-09-28 01:05 in Propeller 1
I want to study input words and commands through a propeller chip， anyone who can tell me where to get some circuits or examples .

thanks!

Comments

  • frank freedmanfrank freedman Posts: 1,983
    edited 2011-09-27 18:44
    daniel ding wrote: »
    I want to study input words and commands through a propeller chip， anyone who can tell me where to get some circuits or examples .

    thanks!

    For an easy start that will help you understand the principles of a scanned matrix keyboard, check out the 74C92X chip, a 16/20 key encoder chip that can be had through a few sources. After looking at that datasheet, if you are impatient enough, you could actually use 8 I/O pins of your prop chip to set up an 4*4 matrix and create your own 16 key keyboard. Once it sort of works, you could then play around with some delays to provide debounce of the switch presses. When you really get ambitious, you can then add in more delay sequences to cause things like short press single events, longer presses slower/faster/multiple events, etc. Then you can create your own commands determine how they cause/control process' you design. Keys can be abc, 123, start/stop, whatever you define them to be with software.

    So, you can buy a chip to learn some of this, or you can build from scratch and get a feel and mastery of much more. Your choice. Check the OBEX to see how others have done it, look in half price book stores for old skool stuff like the 8080/z80 era homebuilt stuff to learn from. But either way,

    Have Fun Doin It,

    Frank
  • Mike GreenMike Green Posts: 23,101
    edited 2011-09-27 21:16
    There is a PS/2 keyboard and mouse I/O driver in the OBEX here. There are other keyboard I/O drivers in the OBEX as well. Use the Demo Board schematic as an example of how to connect a PS/2 keyboard and/or mouse to a Propeller.
  • Clive WakehamClive Wakeham Posts: 152
    edited 2011-09-28 00:26
    daniel ding wrote: »
    I want to study input words and commands through a propeller chip， anyone who can tell me where to get some circuits or examples .

    thanks!

    Check out my objects for the 74C922 16 key encoder IC http://obex.parallax.com/objects/725/
    and for the 74C923 20 key encoder IC http://obex.parallax.com/objects/726/

    By using the info in the included pdf file you can have the 74C922 become a 32 key encoder IC with additional parts.

    Regards,
  • daniel dingdaniel ding Posts: 52
    edited 2011-09-28 01:05
    Thanks a lot！
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