CDNC_UART_MODEM_CTRL_REG_DTR
WR4(bas, CDNC_UART_MODEM_CTRL_REG, CDNC_UART_MODEM_CTRL_REG_DTR |
~(CDNC_UART_MODEM_CTRL_REG_DTR | CDNC_UART_MODEM_CTRL_REG_RTS);
modem_ctrl |= CDNC_UART_MODEM_CTRL_REG_DTR;