cf209fce4d
arduino uses TCA timer to do its things. it doesn't need to do anything while the MCU is in low power sleep. disable TCA whenever entering sleep from user code. note that the prior "working" demo commented using the rgb_run_next sleep loop in the program. was still diagnosing issues with TCB0 interrupt. if there's still issues waking from idle with TCB interrupt, then things will still need to be addressed... this fix is untested.