Comment by userbinator
Comment by userbinator a day ago
Of course, the project didn’t allow us to use an RTOS.
That tends to just make the project eventually implement an approximation of one... as what appears to have happened here.
How I'd solve the given problem is by using the PWM peripheral (or timer interrupts if no PWM peripheral exists) and pin change interrupts, with the CPU halted nearly 100% of the time. I suspect that approach is even simpler than what's shown here.
You should not use interrupts for button inputs. You will just end up hammering the processor with useless interrupts when the switch bounces. Human interfaces can be polled and still maintain responsiveness. If polling isn't fast enough for machine actuated IO or you need to stay in a low power state then interrupts could be considered but you really need a non-naive solution that disables the interrupt from within the handler for a specified timeout duration.