HDLC_CMD_RRS
hdlc->ctrl.sr.cmd = HDLC_CMD_XRS | HDLC_CMD_RRS;
hdlc->ctrl.sr.cmd = HDLC_CMD_XRS | HDLC_CMD_RRS;
hdlc->ctrl.sr.cmd = HDLC_CMD_XRS | HDLC_CMD_RRS;
hdlc->ctrl.sr.cmd |= HDLC_CMD_RRS;
hdlc->ctrl.sr.cmd &= ~HDLC_CMD_RRS;