I want to build a 2 octave keyboard with some extras, mainly a rotary switch button and a LCD screen.
Just the 25 keys would use at least 25 digital pins. Based on the header tables linked below, I should be able to have 36 total pins. Is this correct?
https://raw.githubusercontent.com/wiki/BelaPlatform/Bela/BeagleboneBlackBelaP8HeaderTable.pdf
https://raw.githubusercontent.com/wiki/BelaPlatform/Bela/BeagleboneBlackBelaP9HeaderTable.pdf
P8 by $PIN (total: 15 pins)
9
10
11
8
31
54
55
53
51
52
50
48
49
46
47
P9 by $PIN (total: 5 pins)
28
29
105
109
89
In P8, why are all the numbers 47-54 (in my list) highlighted red?
In p9, why is 105 highlighted purple?
Is the following math correct?
16 bela gpio + 15 P8 gpio + 5 p9 gpio = 36 avaialble digital gpio
If this not a good idea or not worthwhile, I will probably use a secondary controller and pass the button information in via midi or osc over usb.