Oh, good point, yes. It's just a combination of inputs rather than some kind of stream of states isn't it. I'm rusty. The 9 pin pinout has 2 spare button input

Oh, good point, yes. It's just a combination of inputs rather than some kind of stream of states isn't it. I'm rusty. The 9 pin pinout has 2 spare button inputs anyway. Maybe it'd be feasible to use those.