.\" $FreeBSD$
.Dd December 1, 2003
.Os
.Dt SX 4
.Sh NAME
.Nm sx
.Nd "driver for Specialix International I/O8+ multiport serial card"
.Sh SYNOPSIS
.Cd "device sx"
.Sh DESCRIPTION
The
.Nm
device driver provides support for the CD1865-based Specialix I/O8+
multiport serial card.  Each I/O8+ card supports eight ports; this
driver supports any number of cards.
.Pp
The input and output bit rate for each port may be set independently to
75, 110, 150, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600 or
115200 bps.  The card, however, is simply not fast enough to drive all
eight ports at 115200 bps simultaneously.  Trying to do this is
guaranteed to drop characters.  Note also that at 57600 and 115200 bps,
the programmed bit rate on the card itself is nearly three percent off
the nominal bit rate (rounding error due to the card clock rate make
these actually around 55804 and 111607 bps, respectively).  This is
a function of the design of the I/O8+ itself, not of the
.Nm
device driver.  Be aware that you may have trouble running these cards at
high bit rates.
.Pp
The
.Nm
driver responds appropriately to the
.Xr comcontrol 8
utility.  Additionally, an open on a /dev device node controlled by the
.Nm
driver obeys the same semantics as the
.Xr sio 4
driver.  It fully supports the usual semantics of the cua ports and the
"initial termios" and "locked termios" settings.  (In summary, an open on a
tty port will block until DCD is raised unless O_NONBLOCK is specified.
CLOCAL is honored.  An open on a cua port will always succeed, but DCD
transitions will be honored after DCD rises for the first time.)
.Pp
As each port on the I/O8+ is only assigned six pins, the card can't even
support all of the RS232C signals provided by a DB9 connector.  It doesn't
support the DSR and RI signals at all, but it does support the RTS
and DTR signals, by sharing a single pin between them.  The signal
is in fact DTR but it is used as RTS by wiring it to the RTS pin of the
DB9 or DB25 connector.  A bit in the minor number of the device, discussed
later, indicates the configuration for each port.
.Pp
Any number of I/O8+ PCI cards may be controlled by the sx driver.
.Pp
The lowest three bits of the minor device number are used to select the
channel (port number) on the card.
The next bit, bit four, indicates whether the cable on this port was wired with
the DTR signal connected to the DTR or RTS pin; if this bit is zero, it was
wired as RTS, otherwise it was wired as DTR.  Bit five is unused and must be
zero.  All other bits are used as in the
.Xr sio 4
driver:
.Bd -literal -offset indent
0b\fI000000000000000000000000CLI0DPPP\fR
                          \fBC\fRallout
                           \fBL\fRock
                            \fBI\fRnitial
                              \fBD\fRTR/RTS
                               \fBPPP\fRort
.Ed
.Sh FILES
.Bl -tag -width /dev/cualG{00-07} -compact
.It Pa /dev/ttyG{00-07}
terminal/dialin ports, DTR/RTS wired as RTS.
.It Pa /dev/cuaG{00-07}
dialout ports, DTR/RTS wired as RTS.
.It Pa /dev/ttyiG{00-07}
initial termios state devices, DTR/RTS wired as RTS.
.It Pa /dev/ttylG{00-07}
locked termios state devices, DTR/RTS wired as RTS.
.It Pa /dev/cuaiG{00-07}
initial termios state devices for dialout ports, DTR/RTS wired as RTS.
.It Pa /dev/cualG{00-07}
locked termios state devices for dialout ports, DTR/RTS wired as RTS.
.It Pa /dev/ttyG{08-15}
terminal/dialin ports, DTR/RTS wired as DTR.
.It Pa /dev/cuaG{08-15}
dialout ports, DTR/RTS wired as DTR.
.It Pa /dev/ttyiG{08-15}
initial termios state devices, DTR/RTS wired as DTR.
.It Pa /dev/ttylG{08-15}
locked termios state devices, DTR/RTS wired as DTR.
.It Pa /dev/cuaiG{08-15}
initial termios state devices for dialout ports, DTR/RTS wired as DTR.
.It Pa /dev/cualG{08-15}
locked termios state devices for dialout ports, DTR/RTS wired as DTR.
.El
.Sh SEE ALSO
.Xr stty 1 ,
.Xr sio 4 ,
.Xr termios 4 ,
.Xr tty 4 ,
.Xr comcontrol 8
.Sh HISTORY
This driver is derived from the
.Xr si 4
driver by
.An Peter Wemm Aq peter@netplex.com.au ,
using lots of information from the Linux "specialix" driver by
.An Roger Wolff Aq R.E.Wolff@BitWizard.nl
and from the Intel CD1865 "Intelligent Eight-Channel Communications
Controller" datasheet.  Roger was also nice enough to answer numerous
questions about stuff specific to the I/O8+ not covered by the CD1865
datasheet.
.Pp
This driver is not supported by Specialix International (now Perle Systems).
.Sh AUTHORS
.An -nosplit
.An Frank Mayhar Aq frank@exit.com
wrote the driver, with a lot of help from
.An Roger Wolff Aq R.E.Wolff@BitWizard.nl .
.Sh BUGS
Plenty, I'm sure.
.Pp
Polled mode (a feature of standard Specialix drivers) is not implemented.
.Pp
The driver does not support nonstandard bit rates, although it could.
.Pp
The ISA version of the card is not yet supported.
.Pp
Multiple cards support has not been tested.