EIA(3)EIA(3)NAMEeia - serial communication control
SYNOPSIS
bind -a '#t' /dev
/dev/eia0
/dev/eia0ctl
/dev/eia0status
/dev/eia1
/dev/eia1ctl
/dev/eia1status
...
DESCRIPTION
The serial line device serves a one-level directory that gives access
to the serial ports. Each file set eian ... represents one serial
port and includes a data file (eg, eia0), a control file (eg, eia0ctl),
and a status file (eg, eia0status).
The data file can be read and written to access the corresponding
serial port. Reads will block until at least one character is avail‐
able.
The ctl file accepts textual commands, via write (see sys-read(2)),
that control or condition the serial port for subsequent IO:
bn Set the baud rate to n.
cn If n is non-zero, cause a hangup if the remote drops DCD.
dn Set DTR if n is non-zero; otherwise clear it.
en If n is non-zero, cause a hangup if the remote drops DSR.
f Flush the output queue.
h Hangup both input and output queues.
kn Send a break lasting n milliseconds.
ln Set number of bits per byte to n. Legal values are 5, 6, 7, or
8.
mn Obey modem CTS signal if n is non-zero; otherwise clear it.
nn Set the output queue to non-blocking, if n is non-zero; other‐
wise mark it as blocking (the default). In non-blocking mode,
if the output queue is full, new output is discarded rather than
block the writer until the queue drains.
pc Set parity to odd if c is o, to even if c is e; otherwise set no
parity.
qn Set the limit on input and output queues to n; both queues are
initially set to 4k bytes.
rn Set RTS if n is non-zero; otherwise clear it.
sn Set number of stop bits to n. Legal values are 1 or 2.
xn Enable XON/XOFF flow control if n is non-zero; otherwise disable
it (the default).
Changes to port settings persist between a subsequent close and reopen.
The status file can be read for a report of the serial port status.
SOURCE
/os/port/devns16552.c
/os/*/devuart.c
/os/*/devscc.c
EIA(3)
