tim-systick-monotonic Select which timer pair to use with features, currently supported: l0x1-tim21-tim22 - STM32L0x1 TIM21+TIM22 f0x1-tim15-tim17 - STM32F0x1 TIM15+TIM17 f0x1-tim15-tim16 - STN32F0x1 TIM15+TIM16 Other timer combinations are possible as well.