The Specialix SI/XIO and SX hardware makes up an 8 to 32 port RS-232 serial
The system uses two components: a "Host adapter", which is plugged into
an ISA, EISA or PCI slot and provides intelligence and buffering/processing
capabilities, as well as an external bus in the form of a 37 pin cable.
On this cable, "modules" are connected.
The "SI" module comes in a 4 and 8 port version.
The "XIO" and "SX" modules come only in
8 port versions.
The host adapter polls and transfers data between the modules and the rest
of the machine.
The Host adapter provides a 256 byte transmit and 256 byte
receive FIFO for each of the 32 ports that it can maintain.
The XIO modules can operate each of their 8 ports at 115,200 baud.
The SI version can run at 57,600 baud.
The SX modules can operate each of their
8 ports at up to 921,600 baud.
SX modules are only supported when connected to an SX host card.
XIO modules are supported on any host card.
The host adapter uses a shared memory block in the traditional ISA bus
"hole" between 0xA0000 and 0xEFFFF.
The adapter can be configured outside
range, but requires the memory range to be explicitly non-cached.
The driver does not yet support this mode of operation.
SX ISA Host cards have an 8/16 bit mode switch or jumper on them.
or jumper MUST be set for 8 bit mode.
The ISA adapters can use Irqs 11, 12 or 15 (and 9 and 10 in the case of
SX host cards).
The si device driver may have some of its configuration settings changed
at run-time with the
The si device driver also responds to the
utility for configuring drain-on-close timeouts.
The driver also defines 3 sysctl variables that can be manipulated:
machdep.si_debug sets the debug level for the whole driver.
on the driver being compiled with SI_DEBUG.
sets how often per second the driver polls for lost interrupts.
machdep.si_realpoll sets whether or not the card will treat the
poll intervals as if they were interrupts.
An open on a /dev device node controlled by the si driver obeys the same
semantics as the
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.
Up to four SI/XIO host cards may be controlled by the si driver.
Due to the lack of available interrupts, only 3 ISA SI/XIO host cards can be
used at once.
The lowest 5 bits of the minor device number are used to select the port
number on the module cluster.
The next 2 bits select which of 4 host adapter
This allows a maximum of 128 ports on this driver.
Bit 7 is used to differentiate a tty/dialin port (bit 7=0) and a
cua/callout port (bit 7=1).
Bit 8 through 15 (on
are unavailable as they are a shadow of the
major device number.
If bit 16 is a 1, the device node is referring to the "initial state" device.
This "initial state" is used to prime the
settings of the device when it is initially opened.
If bit 17 is a 1, the device node is referring to the "locked state" device.
The "locked state" is used to prevent the
settings from being changed.
To manipulate the initial/locked settings, the
command is useful.
When setting the "locked" variables, enabling the mode
on the lock device will lock the termios mode, while disabling the mode will
The interrupt tuning rate is not believed to be optimal at this time for
Polled mode (a feature of standard Specialix drivers) is not implemented,
but it can be approximated by turning on machdep.si_realpoll.
frequency is set by machdep.si_pollrate (in units of 1/100th of a second).
The driver does not yet support baud rates higher than 115,200 on SX
Operation outside the traditional ISA "hole" is not yet supported, although it
should work if the test is removed from the probe routine.
Multiple host cards are supported although combinations of hosts on
different bus types have not been tested - device numbering is known to
be a problem and may lead to unexpected results.