Integration test: combined input from several buttons and a rotary encoder

March 19, 2026 ยท View on GitHub

Purpose and summary

To test correct identification and combination of events caused by different kinds of digital inputs. Individual events are combined into a global state bitmap (one bit for each input).

Hardware setup

Use this test circuit:

Test circuit image

We are using the KY-040 rotary encoder and the button matrix.

Output through USB serial port at 115200 bauds.

For later reference:

  • "BM1" is the button in the matrix whose output is:

    STATE : 0000000000000000000000000000000000000000000000000000000000000100

  • "ROT" is the built-in push button in the rotary encoder.

  • "RCW" means rotary clockwise rotation.

  • "RCCW" means rotary counter-clockwise rotation.

Procedure and expected output

  1. Reset

  2. On start, output must match the following:

    -- READY --
-- GO --
STATE : 0000000000000000000000000000000000000000000000000000000000000000

  3. Press and hold ROT, then press and hold BM1, then release ROT, then release BM1. Output must match the following:

    STATE : 0000000000000000000000000000000000000000000000000000010000000000
STATE : 0000000000000000000000000000000000000000000000000000010000000100
STATE : 0000000000000000000000000000000000000000000000000000000000000100
STATE : 0000000000000000000000000000000000000000000000000000000000000000

  4. Input RCW one detent, then RCCW one detent. Output must match the following:

    STATE : 0000000000000000000000000000000000000000000000000001000000000000
STATE : 0000000000000000000000000000000000000000000000000000000000000000
STATE : 0000000000000000000000000000000000000000000000000010000000000000
STATE : 0000000000000000000000000000000000000000000000000000000000000000

  5. Press and hold ROT, input RCW one detent, then RCCW one detent, then release ROT. Output must match the following:

    STATE : 0000000000000000000000000000000000000000000000000000010000000000
STATE : 0000000000000000000000000000000000000000000000000001010000000000
STATE : 0000000000000000000000000000000000000000000000000000010000000000
STATE : 0000000000000000000000000000000000000000000000000010010000000000
STATE : 0000000000000000000000000000000000000000000000000000010000000000
STATE : 0000000000000000000000000000000000000000000000000000000000000000