arduino btn_matrix example
| btn_pin | mode |
|---|---|
| 4 | INPUT_PULLUP |
| 5 | INPUT_PULLUP |
| 7 | OUTPUT |
| 6 | OUTPUT |
have 4 buttons bt1 bt2 bt3 bt4
have 4 lines line1 line2 line3 line4
bt1-leg1 connected to bt2-leg1 (line1)
bt1-leg2 connected to bt4-leg2 (line2)
bt2-leg2 connected to bt3-leg2 (line3)
bt3-leg1 connected to bt4-leg1 (line4)
line to pin
line1 -> 4 line2 -> 6 line3 -> 5 line3 -> 7