ss.4

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 4 代码 · 共 176 行

.\" SCCSID: @(#)ss.4	8.1	9/11/90
.TH ss 4 VAX
.SH Name
ss \- Small VAX serial line interface
.SH Syntax
.B "device ss0 at uba0 csr 0x200a0000 flags 0x0f"
.br
.ti +0.5i
.B "vector ssrint ssxint"
.SH Description
.NXS "ss interface" "Small VAX serial line interface"
.NXR "Small VAX serial line interface"
The Small VAX serial line controller is similar to
the DZQ11 4-line communications multiplexer.
An 
.PN ss
interface provides four communication ports with partial modem control
on port 2, adequate for dialup use.
Only port 2 supports modem control (dialup access).
All other ports must be operated as local lines.
Each line attached to the serial line controller
behaves as described in
.MS tty 4
and may be set to run at any of 16 speeds. 
For the encoding, see
.MS tty 4 .
However, configuration requirements dictate fixed speed
operation of ports connected to the console terminal and
graphics devices.
.PP
The Small VAX may be configured as a workstation or
a multiuser timesharing system.
For the workstation configuration,
the 
.PN ss 
ports are used as follows:
.sp
.nf
\fBPort\fR      \fBUsage\fR
.br
0         Graphics device keyboard at 4800 BPS
1         Mouse or tablet at 4800 BPS
2         Communications (with modem control)/local terminal
3         Serial printer port
.fi
.sp
For the multiuser configuration,
the 
.PN ss 
port usage is:
.sp
.nf
\fBPort\fR      \fBUsage\fR
.br
0         Console terminal at 9600 BPS
1         Local terminal line
2         Communications (with modem control)/local terminal
3         Local terminal or serial printer 
.fi
.PP
For either configuration, a diagnostic console terminal
may be connected to port 3 using a BCC08 cable.
For the multiuser configuration, while the diagnostic console
is connected, no other terminal devices can be connected.
When the diagnostic console is in use,
the processor may be halted by pressing the BREAK key.
.PP
The selection of which port to use for the console
is made during the processor's power-on sequence
and cannot be changed after power on.
If the diagnostic console is connected, it is used;
otherwise, the device connected to port 0 is the console.
.PP
For the 
.PN ss 
device,
the flags should always be specified as: flags 0x0f
(all 4 lines hardwired).
The state of port 2 can be established by specifying either
modem or nomodem as part of the 
.PN /etc/ttys 
file entry for tty02;
see
.MS ttys 5 .
The default state of port 2 can be controlled by
flags bit 2.
Set `flags 0x0f' for a hardwired line,
`flags 0x0b' for dialup operation (wait for carrier).
.PP
The 
.PN ss 
driver operates in interrupt-per-character mode
(all pending characters are flushed from the silo on each interrupt).
Silo alarm mode is used by the DZQ11 driver at times of high input
character traffic.  This mode is not used by the 
.PN ss 
driver,
due to the need to track mouse or tablet position changes
in real time.
.SS "VAXstation 3100 Communications and Printer Ports"
The VAXstation 3100 has two MMJ (Modified Modular Jack) connectors located
at the rear of the system box. These MMJ connectors allow connection of 
terminals, printers, and modems to the VAXstation 3100 system.
.PP
The ULTRIX logical names for these connectors are 
.PN /dev/tty02 
(the MMJ closest to the power connector) and 
.PN /dev/tty03 
(the MMJ next to the graphics connector).
.PP
Terminals and printers can be connected to either the 
.PN /dev/tty02 
or
.PN /dev/tty03 
MMJ.  Modems can be connected only to the 
.PN /dev/tty02 
MMJ.
.PP
The VAXstation 3100 hardware provides only limited modem control support.
The DTR (Data Terminal Ready) and DSR (Data Set Ready) signals are the only
modem control signals available at the 
.PN /dev/tty02 
MMJ.  The ULTRIX device driver for 
.PN /dev/tty02 
has been modified to allow modems to function
with the limited modem control provided by the VAXstation 3100.  For the 
modem to function properly, it must be configured to drop DSR when 
the carrier drops; that is, the modem should not continuously assert DSR.

.SH Restrictions
The speed must be set to 9600 BPS on the console port and
4800 BPS on ports used by graphics devices.
The console device must be set for 8-bit character length with one stop bit 
and no parity.
The 
.PN ss 
driver enforces these restrictions; 
that is, changing speeds with the 
.PN stty 
command may
not always work on these ports.
.SH Diagnostics
.B "ss0: input silo overflow"
.br
The 64-character input silo overflowed
before it could be serviced.  This can happen if a hard error occurs
when the CPU is running with elevated priority, as the system 
then prints a message on the console with interrupts disabled.
.SH Files
.TP 20
.PN /dev/console
console terminal or graphics device
.TP
.PN /dev/tty00
not used
.TP
.PN /dev/tty01
local terminal \- multiuser configuration only
.TP
.PN /dev/tty02
dialup or local terminal
.TP
.PN /dev/tty03
printer port or local terminal
.TP
.PN /dev/mouse
mouse or tablet \- workstation configuration only
.TP
.PN /dev/smscreen
console message window for monochrome workstations
.TP
.PN /dev/sgscreen
console message window for color workstations
.SH See Also
console(4), devio(4), sm(4), tty(4), ttys(5), MAKEDEV(8)