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    Length: 1942 (0x796)
    Types: TextFile
    Notes: UNIX file
    Names: »sio.4«

└─⟦26887b7e0⟧ Bits:30009717 Comet 32 harddisk image
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        └─⟦this⟧ »usr/man/man4/sio.4« 

TextFile

.ig
	@(#)sio.4	2.1	7/1/84
	@(#)Copyright (C) 1983 by National Semiconductor Corp.
..
.TH SIO 4
.SH NAME
sio \- eight port terminal i/o multiplexer
.SH DESCRIPTION
The serial i/o board provides 8 communication lines
with partial modem control,
adequate for
.SM GENIX
dialup use.
Each line attached to the serial i/o board
behaves as described in
.IR tty (4).
Lines may independently be set to run at any of 16 speeds.
The encoding is given in
.IR tty (4);
however,
200 baud is not supported and 
19200 baud is available
(although not recommended)
using the
.SM EXTA
setting.
.PP
The sio driver currently takes an interrupt
on every incoming character.
In the future the driver may instead use
the sio board's fifo and poll for input at each clock tick.
.PP
The file
.I /usr/include/sys/sio.h
contains definitions and declarations describing the sio board.
.SH FILES
.nf
/dev/tty0[0-7]
/dev/ttyd[0-7]	dialups
.fi
.SH "SEE ALSO"
tty(4)
.SH DIAGNOSTICS
.B
sio%d: unexpected interrupt %x.
The driver got an unexpected kind of interrupt.
The sio board can generate five different interrupts,
one of which the driver does not use.
Expected interrupts are
.SM I_DONE,
signifying
.SM DMA
completion,
.SM I_FIFO,
indicating that an incoming character has arrived
(or that the fifo is \(34 full,
when in
.SM C_INT_MANY
mode),
.SM I_MODEM,
indicating a line transition,
and
.SM I_ERROR,
which is discussed below.
The unexpected interrupt is
.SM I_DIAG,
which the board generates when completing internal diagnostics.
Getting an unexpected interrupt is harmless in itself,
but may be a sign of trouble elsewhere.
.PP
.B
sio%d: fifo overrun.
The fifo overflowed,
causing one or more characters to be lost.
.PP
.B
sio%d: dma transfer error.
The sio board has generated its
.SM I_ERROR
interrupt,
which signifies an error in transferring information
from main memory to the sio board,
resulting in garbled output.
This message is a sign of hardware trouble.