sasy(7) —
NAME
sasy − SunRiver asynchronous serial port
DESCRIPTION
The sasy driver supports both serial ports on the SunRiver Cygna 386 Station. If a station is not connected, an attempt to open its serial ports will fail. The ports can be programmed for speed (50-19200 baud), character length, and parity. Output speed is always the same as input speed. The ports behave as described in termio(7).
The asynchronous port is a character-at-a-time device for both input and output. This characteristic both limits the bandwidth which can be achieved over a line, and increases the interrupt loading on the central processor. In particular, file transfer programs such as uucp(1) may not function well at speeds over 9600 baud.
If the port was opened with the modem control bit present in the minor device number (see below), modem control will be enabled. If enabled, the driver will wait in open until Data Carrier Detect is present. Once opened, if Data Carrier Detect drops, the driver will return errors on any subsequent reads or writes of the asynchronous port by the user. If the port was opened as a controlling teletype, signal SIGHUP will be generated to the process which did the open.
The baud rates of the serial adapter programmable baud-rate generator do not correspond exactly with system baud rates. In particular, setting B0 will cause a disconnect, setting EXTA will set 19200 baud, and setting EXTB will set 38400 baud. It is not possible to directly set 2000, 3600, or 7200 baud.
Minor Device Numbers
The asynchronous port is a character device. The low-order 4 bits (bits 0-3) of the minor device number correspond to the station at which the port is located. Bit 4 enables modem control on the port. Thus, minor device 0 corresponds to the system board serial port with no modem control, while minor device 16 corresponds to the same port with modem control enabled.
FILES
/dev/ser*
SEE ALSO
asy(7), slp(7), termio(7).
signal(2) in the INTERACTIVE SDS Guide and Programmer’s Reference Manual.
ADDED VALUE
This entry, supplied by INTERACTIVE Systems Corporation, is an extension of UNIX System V.
\*U — Version 1.0