CY(4) BSD Kernel Interfaces Manual CY(4)
cy -- Cyclades Cyclom-Y serial driver
For one ISA card:
For two ISA cards:
For PCI cards:
No lines are required in /boot/device.hints for PCI cards.
The cy driver provides support for Cirrus Logic CD1400-based EIA RS-232C
(CCITT V.24) communications interfaces (ports) on Cyclades Cyclom-Y
boards. Each CD1400 provides 4 ports. Cyclom-Y boards with various num-
bers of CD1400's are available. This driver supports up to 8 CD1400's
(32 ports) per board.
Input and output for each line may set independently to the following
speeds: 50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
19200, 38400, 57600, or 115200 bps. Other speeds of up to 150000 are
supported by the termios interface but not by the sgttyb compatibility
interface. The CD1400 is not fast enough to handle speeds above 115200
bps effectively. It can transmit on a single line at slightly more than
115200 bps, but when 4 lines are active in both directions its limit is
about 90000 bps on each line.
Serial ports controlled by the cy driver can be used for both `callin'
and `callout'. For each port there is a callin device and a callout
device. The minor number of the callout device is 128 higher than that
of the corresponding callin port. The callin device is general purpose.
Processes opening it normally wait for carrier and for the callout device
to become inactive. The callout device is used to steal the port from
processes waiting for carrier on the callin device. Processes opening it
do not wait for carrier and put any processes waiting for carrier on the
callin device into a deeper sleep so that they do not conflict with the
callout session. The callout device is abused for handling programs that
are supposed to work on general ports and need to open the port without
waiting but are too stupid to do so.
The cy driver also supports an initial-state and a lock-state control
device for each of the callin and the callout "data" devices. The minor
number of the initial-state device is 32 higher than that of the corre-
sponding data device. The minor number of the lock-state device is 64
higher than that of the corresponding data device. The termios settings
of a data device are copied from those of the corresponding initial-state
device on first opens and are not inherited from previous opens. Use
stty(1) in the normal way on the initial-state devices to program initial
termios states suitable for your setup.
The lock termios state acts as flags to disable changing the termios
state. E.g., to lock a flag variable such as CRTSCTS, use stty crtscts
on the lock-state device. Speeds and special characters may be locked by
setting the corresponding value in the lock-state device to any nonzero
Correct programs talking to correctly wired external devices work with
almost arbitrary initial states and almost no locking, but other setups
may benefit from changing some of the default initial state and locking
the state. In particular, the initial states for non (POSIX) standard
flags should be set to suit the devices attached and may need to be
locked to prevent buggy programs from changing them. E.g., CRTSCTS
should be locked on for devices that support RTS/CTS handshaking at all
times and off for devices that don't support it at all. CLOCAL should be
locked on for devices that don't support carrier. HUPCL may be locked
off if you don't want to hang up for some reason. In general, very bad
things happen if something is locked to the wrong state, and things
should not be locked for devices that support more than one setting. The
CLOCAL flag on callin ports should be locked off for logins to avoid cer-
tain security holes, but this needs to be done by getty if the callin
port is used for anything else.
Kernel Configuration Options
The CY_PCI_FASTINTR option should be used to avoid suboptimal interrupt
handling for PCI Cyclades boards. The PCI BIOS must be configured with
the cy interrupt not shared with any other active device for this option
to work. This option is not the default because it is currently harmful
in certain cases where it does not work.
/dev/ttyc?? for callin ports
/dev/ttylc?? corresponding callin initial-state and lock-state devices
/dev/cuac?? for callout ports
/dev/cualc?? corresponding callout initial-state and lock-state devices
/etc/rc.serial examples of setting the initial-state and lock-state
The first question mark in these device names is short for the card num-
ber (a decimal number between 0 and 65535 inclusive). The second ques-
tion mark is short for the port number (a letter in the range [0-9a-v]).
cy%d: silo overflow. Problem in the interrupt handler.
cy%d: interrupt-level buffer overflow. Problem in the bottom half of the
cy%d: tty-level buffer overflow. Problem in the application. Input has
arrived faster than the given module could process it and some has been
stty(1), termios(4), tty(4), comcontrol(8), pstat(8)
The cy driver is derived from the sio driver and the NetBSD cy driver and
is currently under development.
Serial consoles are not implemented.
BSD May 24, 2004 BSD