ZSR15_TX_UNDER
wr15 = ZSR15_BREAK | ZSR15_TX_UNDER | ZSR15_CD | ZSR15_CTS;
wr15 = ZSR15_BREAK | ZSR15_TX_UNDER | ZSR15_CD;
SCC_WRITE(15, ZSR15_BREAK | ZSR15_TX_UNDER |
(ZSR15_TX_UNDER | ZSR15_BREAK | ZSR15_SYNC | ZSR15_CTS);
(ZSR15_TX_UNDER | ZSR15_BREAK | ZSR15_SYNC);
(ZSR15_TX_UNDER | ZSR15_BREAK | ZSR15_SYNC | ZSR15_CTS));