NAME    [Toc]    [Back]

     cy - Cyclades Cyclom-{4, 8, 16}Y  asynchronous  comms  board
device driver

SYNOPSIS    [Toc]    [Back]

     cy0 at isa? iomem 0xd4000 irq 12
     cy* at pci?

DESCRIPTION    [Toc]    [Back]

     This driver provides an interface to Cyclades Cyclom-4Y, Cyclom-8Y and
     Cyclom-16Y  asynchronous  multiport  serial  boards.   These
boards are based
     around Cirrus Logic CD1400 communication controllers.

     The device minor numbers for this driver are encoded as follows:

         d c c u u u u u     - bits in the minor device number

         bits    meaning
         ----    -------
         uuuuu   physical serial line (i.e., unit) to use
                     0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y

         cc      card number

         d       dial-out flag

DIAGNOSTICS    [Toc]    [Back]

     cy%d: tty input queue  overflow   Incoming  characters  have
been discarded
     due  to a buffer overflow.  This is caused by the process in
control of
     the device not read(2)'ing characters fast enough.

     cy%d: receive fifo overrun  Incoming  characters  have  been
discarded due
     to  a  CD1400 channel overrun.  This is caused by interrupts
not being serviced
 sufficiently quickly to prevent the  12  byte  receive
FIFO on a serial
  channel  from  overflowing.   Reducing  the value of the
RxFifoThreshold
     #define from 8 to something smaller may help  slow  machines
avoid this
     problem.   The  driver  must  have  been  compiled  with the
LogOverruns option
     defined (the default) in order  for  this  condition  to  be
logged.

SEE ALSO    [Toc]    [Back]

     com(4), intro(4), isa(4), pci(4), termios(4), tty(4)

HISTORY    [Toc]    [Back]

     Some  ideas  for the architecture of this driver's two-layer
processing
     model were derived from the fas 2.10 driver by Uwe Doering
     <gemini@geminix.in-berlin.de> and the  high-performance  com
driver by
     Bruce Evans <bde@kralizec.zeta.org.au>.

     This  work  was  made possible through the donation of a Cyclom-8Y board by
     the manufacturer, Cyclades  Corporation.   However,  neither
Cyclades nor
     the  author make any warranties regarding this software, nor
guarantees of
     support.

AUTHORS    [Toc]    [Back]

     The  driver  was  written  by  Andrew  Herbert  <andrew@werple.apana.org.au>.

BUGS    [Toc]    [Back]

     There  is  currently no BREAK handling - breaks are ignored.
There is no
     support for bad-character reporting, except via PARMRK.  The
Cyclom-[48]Y
     boards  do  not  listen  to the RTS signal for receiver flow
control.  FIFO
     overruns are only logged when the termios IGNPAR setting  is
enabled.

OpenBSD      3.6                          October     5,     1993