extern uint16_t ao_adc_ring[AO_ADC_RING_SIZE];
#define ao_adc_ring_step(pos,inc) (((pos) + (inc)) & (AO_ADC_RING_SIZE - 1))
extern uint16_t ao_adc_ring_head, ao_adc_ring_tail;
extern uint16_t ao_adc_ring[AO_ADC_RING_SIZE];
#define ao_adc_ring_step(pos,inc) (((pos) + (inc)) & (AO_ADC_RING_SIZE - 1))
extern uint16_t ao_adc_ring_head, ao_adc_ring_tail;