cserialio - character driver interface to serial communication ports
On Origin, O2, Octane and Challenge/Onyx systems, the special files
/dev/ttyc* provide a character based interface (as opposed to a streams
based interface) to the system serial ports. The hardware accessed by
each special file is determined by the portno portion of the pathname
(see serial(7) for further details). The character based interface is
intended to provide a low cost option for applications wishing to do bulk
data transfer via the serial ports with no character interpretation.
There is no line discipline associated with this port type and no tty
facilities are provided.
The ttyc ports support a limited subset of the ioctl set used to control
ordinary tty ports. Specifically, ioctl functions which relate directly
to the hardware are supported, whereas ioctl functions which relate to
software functions of the tty interface such as the line discipline are
not supported and may either fail or be silently ignored. In addition,
streams ioctls will fail since this is not a streams device.
For port hardware configuration, the ttyc interface supports the
following ioctls as described in termio(7): TCGETA, TCSETA, TCSETAW,
TCSETAF, TCGETS, TCSETS, TCSETSW, TCSETSF. Not all fields of the termio
struct are relevant to the ttyc interface. The following fields are
supported as described in termio(7): c_ospeed, CSIZE, CSTOPB, PARENB,
PARODD, CNEW_RTSCTS. In addition the port will generate a SIGINT on
reception of a break char if IGNBRK is false and BRKINT is true. Lastly,
reads from ttyc ports will be non-blocking if ICANON is false, and VMIN
and VTIME are 0. All other fields of the termio struct are silently
The ttyc ports also honor the following ioctls as described in termio(7):
Lastly, the following ioctls are supported as described in serial(7):
SIOC_RS422, SIOC_EXTCLK, SIOC_ITIMER.
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