Doremikko Keyboard

The Doremikko Keyboard is a 36-key piano keyboard released by Konami alongside the pack-in FDS game DoReMikko.

The keyboard uses common matrix logic similar to the Family BASIC Keyboard but with diodes for N-key rollover (as typical for musical applications). The keyboard does not contain any sound hardware.

 _____________________________________________
|  _________________________________________  |
| | U U U | U U | U U U | U U | U U U | U U | |
| | U U U | U U | U U U | U U | U U U | U U | | Keys
| | | | | | | | | | | | | | | | | | | | | | | |
|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|
   F G A B C D E F G A B C D E F G A B C D E    Notes
  |-------><------------><------------><----|   Octaves
    1..7        8..19    |   20..31    32..36   Key Numbers
                         |
                      Middle C

(ASCII art courtesy nocash)

There are 21 white keys and 15 black keys for a total of 36 keys spanning two + two-half octaves.

7  bit  0
---- ----
xxxx xxRI
       ||
       |+-- Increment row (TODO: 0->1 or 1->0 transition?)
       +--- 1: Reset to first row (TODO: does this also reset the column?)

7  bit  0
---- ----
xxxK KKKx
   | |||
   +-+++--- Receive key status of currently selected row/column.

Reading this register toggles between the two columns. Any key that is held down, will read back as 1.

DoReMikko doesn’t appear to perform long manual delays during the polling process, so there may not be any parasitic capacitances to account for compared to other devices with common matrix logic.

This below matrix maps the row/column to their corresponding key number. Blank entries have unknown contents, and rows beyond 6 are yet to be determined.

• nocash’s documentation
• Forum thread with board photos

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