RDA_UART_RTS
if (cmd_set & RDA_UART_RTS)
rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_SET);
rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_CLR);
cmd_set |= RDA_UART_RTS;
cmd_clr |= RDA_UART_RTS;