HDLC_SEND_DATA
if (hdlc->state == HDLC_SEND_DATA) {
hdlc->state = HDLC_SEND_DATA;
hdlc->state = HDLC_SEND_DATA;
hdlc->state = HDLC_SEND_DATA;
hdlc->state = HDLC_SEND_DATA;
case HDLC_SEND_DATA: