UTSR0_TFS
if (status & UTSR0_TFS)
} while (((tx->index < tx->len) && (status & UTSR0_TFS)) ||
sport->port.read_status_mask &= ~UTSR0_TO_SM(UTSR0_TFS);
sport->port.read_status_mask |= UTSR0_TO_SM(UTSR0_TFS);
status &= SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS;
if (status & UTSR0_TFS)
~UTSR0_TFS;
} while (status & (UTSR0_TFS | UTSR0_RFS | UTSR0_RID));
sport->port.read_status_mask &= UTSR0_TO_SM(UTSR0_TFS);