se(7D) Devices se(7D)
se - Siemens 82532 ESCC serial communications driver
The se module is a loadable STREAMS driver that provides basic support for the 82532 ESCC hardware and basic asynchronous and synchronous
communication support. This manual page describes the asynchronous protocol interface; for information on the synchronous interface, please
see the se_hdlc(7D) manual page.
Note - This module is affected by the setting of specific eeprom variables. For information on parameters that are persistent across
reboots, see the eeprom(1M) man page.
The platform specific device bus address for the se module is bus_address. The se module's port_name is a single letter (a-z).
Note - During boot up, ttya/b characteristics are read from the /kernel/drv/options.conf file and changed from the PROM defaults to
reflect Solaris defaults. Messages displayed on the console after this point are based on settings in that file. If you switch a
characteristic, (for example, the baud rate of the console terminal), you must revise the /kernel/drv/options.conf or the console
will be configured to an unusable configuration and console messages will be garbled by the mismatched serial port settings.
APPLICATION PROGRAMMING INTERFACE
The Siemens 82532 provides two serial input/output channels capable of supporting a variety of communication protocols. A typical system
will use one of these devices to implement two serial ports (port_name), usually configured for RS-423 (which also supports most RS-232
equipment). The Siemens 82532 uses 64 character input and output FIFOs to reduce system overhead. When receiving characters, the CPU is
notified when 32 characters have arrived (one-half of receive buffer is full) or no character has arrived in the time it would take to
receive four characters at the current baud rate.
When sending characters, the Siemens 82532 places the first 64 characters to be sent into its output FIFO and then notifies the CPU when it
is half empty (32 characters left). Because the se module waits for the Siemens 82532 to transmit the remaining characters within its out-
put FIFO before making requested changes, delays may occur when the port's attributes are being modified.
The se module implements CTS/RTS flow control in hardware. To prevent data overruns, remove CTS/RTS flow control responsibility from the
CPU during periods of high system load.
In async mode (obtained by opening /dev/cua/[a-z], /dev/term/[a-z] or /dev/tty[a-z]), the driver supports the termio(7I) device control
functions specified by flags in the c_cflag word of the termios structure, and by the IGNBRK, IGNPAR, PARMRK, or INPCK flags in the c_iflag
word. All other termio(7I) functions must be performed by STREAMS modules pushed atop the driver. When a device is opened, the ldterm(7M)
and ttcompat(7M) STREAMS modules are automatically pushed on top of the stream, providing the standard termio interface.
Each of the following are valid name space entries: /dev/cua/[a-z], /dev/term/[a-z], and /dev/tty[a-z]. The number of entries used in this
name space are machine dependent. The /dev/tty[a-z] device names exist only if the SunOS 4.x Binary Compatibility Package is installed. The
/dev/tty[a-z] device names are created by the ucblinks command, which is available only with the SunOS 4.x Binary Compatibility Package.
You can connect a single tty line to a modem for incoming and outgoing calls using a special feature controlled by the minor device number.
By accessing character-special devices with names of the form /dev/cua/[a-z], it is possible to open a port without the Carrier Detect sig-
nal being asserted, either through hardware or an equivalent software mechanism. These devices are commonly known as dial-out lines.
After a /dev/cua/[a-z] line is opened, the corresponding tty line cannot be opened until the /dev/cua/[a-z] line is closed. A blocking open
will wait until the /dev/cua/[a-z] line is closed (which will drop Data Terminal Ready and Carrier Detect) and carrier is detected again. A
non-blocking open will return an error. If the tty line has been opened successfully (usually only when carrier is recognized on the
modem), the corresponding /dev/cua/[a-z] line cannot be opened. This allows a modem to be attached to a device, (for example, /dev/term/
[a-z] renamed from /dev/tty[a-z]) and used for dial-in (by enabling the line for login in /etc/inittab) and dial-out (by tip(1) or
uucp(1C)) as /dev/cua/[a-z] when no one is logged in on the line.
The se module supports the standard set of termio ioctl() calls.
Breaks can be generated by the TCSBRK, TIOCSBRK, and TIOCCBRK ioctl() calls.
The state of the DCD, CTS, RTS, and DTR interface signals can be queried through the use of the TIOCM_CAR, TIOCM_CTS, TIOCM_RTS, and
TIOCM_DTR arguments to the TIOCMGET ioctl command, respectively. Due to hardware limitations, only the RTS and DTR signals may be set
through their respective arguments to the TIOCMSET, TIOCMBIS, and TIOCMBIC ioctl commands.
The input and output line speeds may be set to all baud rates supported by termio. Input and output line speeds cannot be set indepen-
dently; when you set the output speed, the input speed is automatically set to the same speed.
When using baud rates over 100,000 baud, the software changes the line driver configuration to handle the higher data rates. This action
decreases the theoretical maximum cable length from 70 meters to 30 meters.
When the se module is used to service the serial console port, it supports a BREAK condition that allows the system to enter the debugger
or the monitor. The BREAK condition is generated by hardware and it is usually enabled by default. A BREAK condition originating from erro-
neous electrical signals cannot be distinguished from one deliberately sent by remote DCE. Due to a risk of incorrect sequence interpreta-
tion, SLIP and certain other binary protocols should not be run over the serial console port when Alternate Break sequence is in effect.
Although PPP is a binary protocol, it is able to avoid these sequences using the ACCM feature in RFC 1662. For Solaris PPP 4.0, you do this
by adding the following line to the /etc/ppp/options file (or other configuration files used for the connection; see pppd(1M) for details):
By default, the Alternate Break sequence is a three character sequence: carriage return, tilde and control-B (CR ~ CTRL-B), but may be
changed by the driver. For information on breaking (entering the debugger or monitor), see kadb(1M) and kb(7M).
An open() will fail under the following conditions:
ENXIO The unit being opened does not exist.
EBUSY The dial-out device is being opened and the dial-in device is already open, or the dial-in device is being opened with a
no-delay open and the dial-out device is already open.
EBUSY The port is in use by another serial protocol.
EBUSY The unit has been marked as exclusive-use by another process with a TIOCEXCL ioctl() call.
EINTR The open was interrupted by the delivery of a signal.
/dev/cua/[a-z] dial-out tty lines
/dev/term/[a-z] dial-in tty lines
/dev/tty[a-z] binary compatibility package device names
/dev/se_hdlc[0-9] synchronous devices - see se_hdlc(7D).
/dev/se_hdlc synchronous control clone device
/kernel/drv/options.confSystem wide default device driver properties
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Architecture |SPARC |
tip(1), kadb(1M), ucblinks(1B), cu(1C), uucp(1C), eeprom(1M), ports(1M), pppd(1M), ioctl(2), open(2), attributes(5),zs(7D), zsh(7D),
se_hdlc(7D), termio(7I), ldterm(7M), ttcompat(7M), kb(7M)
sen: fifo overrun The Siemens 82532 internal FIFO received more data than it could handle. This indicates that Solaris was not ser-
vicing data interrupts fast enough and suggests a system with too many interrupts or a data line with a data rate
that is too high.
sen: buffer overrun The se module was unable to store data it removed from the Siemens 82532 FIFO. The user process is not reading
data fast enough, and suggests an overloaded system. If possible, the application should enable flow control
(either CTSRTS or XONXOFF) to allow the driver to backpressure the remote system when the local buffers fill up.
SunOS 5.10 12 Sep 2002 se(7D)