FreeBSD-5.3/share/man/man4/digi.4
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.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91
.\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
.\" from: sio.4,v 1.15 1994/12/06 20:14:30 bde Exp
.\" $FreeBSD: src/share/man/man4/digi.4,v 1.3 2004/05/14 20:07:49 simon Exp $
.\"
.Dd December 7, 2003
.Dt DIGI 4
.Os
.Sh NAME
.Nm digi
.Nd DigiBoard intelligent serial cards driver
.Sh SYNOPSIS
.Cd "device digi"
.Pp
This man page was originally written for the dgb driver, and should
likely be gone over with a fine tooth comb to reflect differences
with the digi driver.
.Pp
When not defined the number is computed:
.Pp
.Bd -ragged -offset 4n
default
.Dv NDGBPORTS
= number_of_described_DigiBoard_cards * 16
.Ed
.Pp
If it is less than the actual number of ports
the system will be able to use only the
first
.Dv NDGBPORTS
ports.
If it is greater then all ports will be usable
but some memory will be wasted.
.Pp
Meaning of
.Cm flags :
.Bl -tag -width indent -compact
.It 0x0001
use alternate pinout (exchange DCD and DSR lines)
.It 0x0002
don't use 8K window mode of PC/Xe
.El
.Pp
Device numbering:
.Bd -literal -compact
0b\fICC\fPmmmmmmmm\fIOLIPPPPP\fP
\fBCC\fPard number
\fRmmmmmmmm\fPajor number
call\fBO\fPut
\fBL\fPock
\fBI\fPnitial
\fBPPPPP\fPort number
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for DigiBoard PC/Xe and PC/Xi series intelligent
serial multiport cards with asynchronous interfaces based on the
.Tn EIA
.Tn RS-232C
.Pf ( Tn CCITT
.Tn V.24 )
standard.
.Pp
Input and output for each line may set to one of following baud rates;
50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
19200, 38400, 57600, or for newer versions of cards 115200.
.Pp
The driver doesn't use any interrupts, it is
.Dq polling-based .
This means that
it uses clock interrupts instead of interrupts generated by DigiBoard cards and
checks the state of cards 25 times per second.
This is practical because the
DigiBoard cards have large input and output buffers (more than 1Kbyte per
port) and hardware that allows efficiently finding the port that needs
attention.
The only problem seen with this policy is slower
SLIP and PPP response.
.Pp
Each line in the kernel configuration file describes one card, not one port
as in the
.Xr sio 4
driver.
.Pp
The
.Cm flags
keyword may be used on each
.Dq Li "device dgb"
line in the kernel configuration file
to change the pinout of the interface or to use new PC/Xe cards
which can work with an 8K memory window in compatibility mode
(with a 64K memory window).
Note
that using 8K memory window doesn't mean shorter input/output buffers, it means
only that all buffers will be mapped to the same memory address and switched as
needed.
.Pp
The
.Cm port
value must be the same
as the
port
set on the card by jumpers.
For PC/Xi cards the same rule is applicable to the
.Cm iomem
value.
It must be the same as the memory address set on the card
by jumpers.
.\"Some documentation gives the address as a ``paragraph'' or ``segment'';
.\"you can get the value of address by adding the digit "0" at end of
.\"paragraph value, e.g., 0xfc000 -> 0xfc0000.
For PC/Xe cards there is no need to use jumpers for this purpose.
In fact there are no jumpers to do it.
Just
write the address you want as the
.Cm iomem
value in kernel config file and the card will be programmed
to use this address.
.Pp
The same range of memory addresses may be used
for all the DigiBoards installed
(but not for any other card or real memory).
DigiBoards
with a large amount of memory (256K or 512K and perhaps
even 128K) must be mapped
to memory addresses outside of the first megabyte.
If the computer
has more than 15 megabytes of memory then there is no free address space
outside of the first megabyte where such DigiBoards can be mapped.
In this case you
may need to reduce the amount of memory in the computer.
But many machines provide a better solution.
They have the ability to
.Dq "turn off"
the memory in the 16th megabyte (addresses 0xF00000 - 0xFFFFFF)
using the
BIOS setup.
Then the DigiBoard's address space can be set to this
.Dq hole .
.\" XXX the following should be true for all serial drivers and
.\" should not be repeated in the man pages for all serial drivers.
.\" It was copied from sio.4. The only changes were s/sio/dgb/g.
.Pp
Serial ports controlled by the
.Nm
driver can be used for both
.Dq callin
and
.Dq callout .
For each port there is a callin device and a callout device.
The minor number of the callout device is 128 higher
than that of the corresponding callin port.
The callin device is general purpose.
Processes opening it normally wait for carrier
and for the callout device to become inactive.
The callout device is used to steal the port from
processes waiting for carrier on the callin device.
Processes opening it do not wait for carrier
and put any processes waiting for carrier on the callin device into
a deeper sleep so that they do not conflict with the callout session.
The callout device is abused for handling programs that are supposed
to work on general ports and need to open the port without waiting
but are too stupid to do so.
.Pp
The
.Nm
driver also supports an initial-state and a lock-state control
device for each of the callin and the callout
.Dq data
devices.
The minor number of the initial-state device is 32 higher
than that of the corresponding data device.
The minor number of the lock-state device is 64 higher
than that of the corresponding data device.
The termios settings of a data device are copied
from those of the corresponding initial-state device
on first opens and are not inherited from previous opens.
Use
.Xr stty 1
in the normal way on the initial-state devices to program
initial termios states suitable for your setup.
.Pp
The lock termios state acts as flags to disable changing
the termios state.
E.g., to lock a flag variable such as
.Dv CRTSCTS ,
use
.Dq Li "stty crtscts"
on the lock-state device.
Speeds and special characters
may be locked by setting the corresponding value in the lock-state
device to any nonzero value.
.Pp
Correct programs talking to correctly wired external devices
.\" XXX change next line in other man pages too, and rewrite this paragraph.
work with almost arbitrary initial states and no locking,
but other setups may benefit from changing some of the default
initial state and locking the state.
In particular, the initial states for non (POSIX) standard flags
should be set to suit the devices attached and may need to be
locked to prevent buggy programs from changing them.
E.g.,
.Dv CRTSCTS
should be locked on for devices that support
RTS/CTS handshaking at all times and off for devices that don't
support it at all.
.Dv CLOCAL
should be locked on for devices
that don't support carrier.
.Dv HUPCL
may be locked off if you don't
want to hang up for some reason.
In general, very bad things happen
if something is locked to the wrong state, and things should not
be locked for devices that support more than one setting.
The
.Dv CLOCAL
flag on callin ports should be locked off for logins
to avoid certain security holes, but this needs to be done by
getty if the callin port is used for anything else.
.Sh FILES
.Bl -tag -width /dev/ttyiD?? -compact
.It Pa /dev/ttyD??
for callin ports
.It Pa /dev/ttyiD??
.It Pa /dev/ttylD??
corresponding callin initial-state and lock-state devices
.Pp
.It Pa /dev/cuaD??
for callout ports
.It Pa /dev/cuaiD??
.It Pa /dev/cualD??
corresponding callout initial-state and lock-state devices
.El
.Pp
.Bl -tag -width /etc/rc.serial -compact
.It Pa /etc/rc.serial
examples of setting the initial-state and lock-state devices
.El
.Pp
The first question mark in these device names is short for the
card number
(a decimal number between 0 and 65535 inclusive).
The second question mark is short for the port number
(a letter in the range [0-9a-v]).
.Sh DIAGNOSTICS
You may enable extended diagnostics by defining DEBUG at the
start of the source file
.Pa dgb.c .
.Bl -diag
.It dgb\fIX\fP: warning: address \fIN\fP truncated to \fIM\fP
The memory address for the PC/Xe's 8K window is misaligned (it should be
on an 8K boundary) or outside of the first megabyte.
.It dgb\fIX\fP: 1st reset failed
Problems with accessing I/O port of the card, probably
the wrong
.Cm port
value is specified in the kernel config file.
.It dgb\fIX\fP: 2nd reset failed
Problems with hardware.
.It dgb\fIX\fP: \fIN\fP[st,nd,rd,th] memory test failed
Problems with accessing the memory of the card, probably
the wrong
.Cm iomem
value is specified in the kernel config file.
.It dgb\fIX\fP: BIOS start failed
Problems with starting the on-board BIOS.
Probably the memory addresses of the
DigiBoard overlap with some other device or with RAM.
.It dgb\fIX\fP: BIOS download failed
Problems with the on-board BIOS.
Probably the memory addresses of the
DigiBoard overlap with some other device or with RAM.
.It dgb\fIX\fP: FEP code download failed
Problems with downloading of the Front-End Processor's micro-OS.
Probably the memory addresses of the
DigiBoard overlap with some other device or with RAM.
.It dgb\fIX\fP: FEP/OS start failed
Problems with starting of the Front-End Processor's micro-OS.
Probably the memory addresses of the
DigiBoard overlap with some other device or with RAM.
.It dgb\fIX\fP: too many ports
This DigiBoard reports that it has more than 32 ports.
Perhaps a hardware problem or
the memory addresses of the
DigiBoard overlap with some other device or with RAM.
.It dgb\fIX\fP: only \fIN\fP ports are usable
The
.Dv NDGBPORTS
parameter is too small and there is only enough space allocated
for
.Ar N
ports on this card.
.It dgb\fIX\fP: port \fIY\fP is broken
The on-board diagnostic has reported that the specified port has hardware
problems.
.It dgb\fIX\fP: polling of disabled board stopped
Internal problems in the polling logic of driver.
.It dgb\fIX\fP: event queue's head or tail is wrong!
Internal problems in the driver or hardware.
.It dgb\fIX\fP: port \fIY\fP: got event on nonexisting port
Some status changed on a port that is physically present but is
unusable due to misconfiguration.
.It dgb\fIX\fP: port \fIY\fP: event \fIN\fP mstat \fIM\fP lstat \fIK\fP
The driver got a strange event from card.
Probably this means that you have a
newer card with an extended list of events or some other hardware problem.
.It dgb\fIX\fP: port \fIY\fP: overrun
Input buffer has filled up.
Problems in polling logic of driver.
.It dgb\fIX\fP: port \fIY\fP: FEP command on disabled port
Internal problems in driver.
.It dgb\fIX\fP: port \fIY\fP: timeout on FEP command
Problems in hardware.
.El
.Sh SEE ALSO
.Xr stty 1 ,
.Xr termios 4 ,
.Xr tty 4 ,
.Xr comcontrol 8
.\" XXX add next line to many other drivers.
.Sh HISTORY
The
.Nm
driver is derived from the
.Xr sio 4
driver and the DigiBoard driver from
.Tn Linux
and is
.Ud
.Sh BUGS
The implementation of sending
.Dv BREAK
is broken.
.Dv BREAK
of fixed length of 1/4 s
is sent anyway.
.Pp
There was a bug in implementation of
.Xr select 2 .
It is fixed now but not widely tested yet.
.Pp
There is no ditty command.
Most of its functions (alternate pinout,
speed up to 115200 baud, etc.) are implemented in the driver itself.
Some
other functions are missing.