USB_CDC_CTRL_DTR
newctrl &= ~USB_CDC_CTRL_DTR;
newctrl |= USB_CDC_CTRL_DTR;
val = USB_CDC_CTRL_DTR | USB_CDC_CTRL_RTS;
return (acm->ctrlout & USB_CDC_CTRL_DTR ? TIOCM_DTR : 0) |
set = (set & TIOCM_DTR ? USB_CDC_CTRL_DTR : 0) |
clear = (clear & TIOCM_DTR ? USB_CDC_CTRL_DTR : 0) |
val |= USB_CDC_CTRL_DTR;