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snsten / Klein

Klein keyboard is a 36 keys, columnar staggered, split ergo keyboard
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Question: why does the wireless version support only OLED *OR* Encoder? #14

Closed bncpr closed 1 year ago

bncpr commented 1 year ago

Hi, why does the seeeduino xiao ble only support either OLED or Encoder. Can't both of then be connected on the I2C bus? Is it a matter of firmware limitation?

snsten commented 1 year ago

Reason for not supporting both OLED and Encoder:

  1. Due to the limited number of pins in XIAO
  2. Both of these can be connected on the same I2C bus, some implications of using this configuration are:
    • The behaviour will depend on how the rotary encoder is designed
    • The encoder could short the line when in rest, check the datasheet for exact behaviour of your encoder
    • It could also interfere with the I2C bus voltage / oled when in use
    • Overall adding two device to same pins will be undefined behaviour in the firmware so I will suggest avoiding it

You can use something like this adapter circuit i2c-encoder-mini safely but you will have to modify and add support for it in the firmware accordingly.

bncpr commented 1 year ago

I see. Thanks for the answer.