TH UART 3

TH UART 3
SH NAME
uart, eia \- serial communication control
SH SYNOPSIS
nf
B bind -a #t /dev

B /dev/eia0
B /dev/eia0ctl
B /dev/eia0status
B /dev/eia1
B /dev/eia1ctl
B /dev/eia1status
\&...
fi
SH DESCRIPTION
PP
The serial line devices serve a one-level directory,
giving access to the serial ports.
Device
I n
is accessed through
BI eia n
(the data file),
BI eia n ctl
(the control file), and
BI eia n status
(the read-only status file).
Reads of the data file will block until at least one byte is available.
The
control file
configures the port.
It accepts the following commands:
TP
BI b n
Set the baud rate to
IR n .
TP
BI c n
Set hangup on DCD if
I n
is non-zero; else clear it.
TP
BI d n
Set DTR if
I n
is non-zero;
else clear it.
TP
BI e n
Set hangup on DSR if
I n
is non-zero; else clear it.
TP
B f
Flush output queue.
TP
B h
Close input and output queues.
TP
BI i n
Enable/disable the FIFOs.
If
I n
is zero the FIFOs are disabled;
otherwise
I n
is taken as a trigger level for the FIFOs.
The trigger levels supported are device dependant,
but usually include 1, 4 and 8.
An unrecognised,
but non-zero,
value of
I n
causes the maximum-supported trigger level to be set.
TP
BI k n
Send a break lasting
I n
milliseconds.
TP
BI l n
Set number of bits per byte to
IR n .
Legal values are 5, 6, 7, or 8.
TP
BI m n
Obey modem CTS signal if
I n
is non-zero;
else clear it.
TP
B n
Make writes non-blocking.
TP
BI p c
Set parity to odd if
I c
is
BR o ,
to even if
I c
is
BR e ;
else set no parity.
TP
BI q n
Set input and output queue limits to
IR n .
TP
BI r n
Set RTS if
I n
is non-zero;
else clear it.
TP
BI s n
Set number of stop bits to
IR n .
Legal values are 1 or 2.
TP
BI w n
Set the uart clock timer to
n times 100us.
IP
PP
The status
files contain a textual representation of the status of the line, in the format of the
commands used on the
control
file.
SH SOURCE
B /sys/src/9/port/devuart.c
br
B /sys/src/9/*/uart*.c