SR_SUB_MODE
rc = at86rf230_write_subreg(lp, SR_SUB_MODE, 0);
rc = at86rf230_write_subreg(lp, SR_SUB_MODE, 1);
rc = atusb_write_subreg(lp, SR_SUB_MODE, 0);
rc = atusb_write_subreg(lp, SR_SUB_MODE, 1);