CLK_LINE
rxs |= CLK_LINE; /* RXC input */
rxs |= CLK_LINE; /* RXC input */
rxs |= CLK_LINE; /* RXC input */
txs |= CLK_PIN_OUT | CLK_LINE; /* TXC input */
rxs |= CLK_LINE; /* RXC input */
rxs |= CLK_LINE; /* RXC input */
rxs |= CLK_LINE; /* RXC input */
txs |= CLK_PIN_OUT | CLK_LINE; /* TXC input */