TPC_DTR
tpc = TPC_TXE | (*tpcp & (TPC_DTR | TPC_RTS));
tpc = TPC_DTR | TPC_RTS;
z8530->tpc = TPC_DTR|TPC_RTS;
z8530->tpc &= ~(TPC_DTR|TPC_RTS);
z8530->tpc |= TPC_DTR;
z8530->tpc &= ~TPC_DTR;