IADC_CONV_TIME_MIN_US
retry = interval_us / IADC_CONV_TIME_MIN_US;
usleep_range(IADC_CONV_TIME_MIN_US, IADC_CONV_TIME_MAX_US);
wait = BIT(IADC_DEF_AVG_SAMPLES) * IADC_CONV_TIME_MIN_US * 2;
ret = iadc_poll_wait_eoc(iadc, IADC_CONV_TIME_MIN_US);