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I want to build a keyboard from scratch, so I started by designing the schematics.

I have found several ones on the web in which the switch - diode direction is connected from row to column, and other in which the switch - diode direction is connected from column to row.

I think that it works fine with both methods, I just wonder if there is a special advantage for the first or the second way.

By the way, for what it matters, I am going to use a Teensy 3.2 M/C with the assorted keyboard libraries. The keyboard columns should be approx. 15 and the rows should be 7.

JRE
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user3060854
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  • As the question stands at the moment we can't answer it as "it depends..." I think you first need to study how a matrix keyboard works. Then you will be able to answer you own question. Also I don't think you will get it working until you do understand how it works. – Oldfart Nov 29 '19 at 15:55
  • The words "row" and "column" have no technical difference. It's up to you to decide which label applies best to which lines. Perhaps you are getting confused by the distinction between driven lines vs. those which are read - that does matter. – Chris Stratton Nov 29 '19 at 16:13
  • @Chris Stratton If you mean by that the Input and the Output signals of the matrix, yes that's exactly what I am asking.Please do explain how that matters. – user3060854 Nov 29 '19 at 16:16
  • Also diodes are superfluous if you limit yourself to one key pressed at a time. – Oldfart Nov 29 '19 at 16:19
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    You have to figure out which your MCU can best support. Note that the more driven lines you have, likely the longer it will take to scan the keyboard. But the count of driven lines can typically more easily be expanded with simple chips external to the MCU, too. – Chris Stratton Nov 29 '19 at 16:19

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