NAME    [Toc]    [Back]

     magma - Magma Sp Serial/Parallel board device driver

SYNOPSIS    [Toc]    [Back]

     magma? at sbus? slot ? offset ?
     mtty? at magma?
     mbpp? at magma?

DESCRIPTION    [Toc]    [Back]

     This driver provides an interface to Magma  LC2+1Sp,  2+1Sp,
4+1Sp, 8+2Sp,
     4Sp,  8Sp,  12Sp,  16Sp,  1P,  2P,  and 2+1HS boards.  These
boards are based
     around the Cirrus Logic  CD1400  serial/parallel  communications engine and
     the Cirrus Logic CD1190 parallel communications engine.

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

         +---+---+---+---+---+---+---+---+
         | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
         +---+---+---+---+---+---+---+---+
           |   |   |   |   |   |   |   |
           |   |   |   |   +---+---+---+---> port number
           |   |   |   |
           |   |   |    +------------------->  dial-out  (on  tty
ports)
           |   |   |
           |   |   +-----------------------> unused
           |   |
           +---+---------------------------> card number

     Up to four cards are supported in the system.

     All  tty  ports  have full automatic hardware (RTS/CTS) flow
control available
 and a 12 byte FIFO on the chip in each direction so errors should be
     minimal.

FILES    [Toc]    [Back]

     /dev/tty[mno][0-f]  Serial ports
     /dev/bpp[mno][0-1]  Parallel ports

DIAGNOSTICS    [Toc]    [Back]

     mtty%d%x:  ring  buffer  overflow   Incoming characters have
been discarded
     due to a buffer overflow.  This is caused by the process  in
control of
     the  device  not reading characters fast enough.  If need be
you can make
     the ring buffer bigger by changing the MAGMA_RBUF_SIZE  #define to something
 bigger, but it should be a multiple of two.

     mtty%d%x:  fifo overflow  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 either the
     MTTY_RX_FIFO_THRESHOLD or MTTY_RX_DTR_THRESHOLD #define's to
something
     smaller may help slow machines avoid this problem.

SEE ALSO    [Toc]    [Back]

     intro(4), sbus(4), tty(4)

HISTORY    [Toc]    [Back]

     The  driver was loosely based upon the cy(4) Cyclades Cyclom
device driver
     written by Andrew Herbert and Timo Rossi.

AUTHORS    [Toc]    [Back]

     The driver was written  by  Iain  Hibbert  <[email protected]-
mon.co.uk>

TODO    [Toc]    [Back]

     CD1190 parallel support.

     bpp input.

     Dial-out (cua) devices are not yet supported.

     mdmbuf is unsupported.

     Automatic  XON/XOFF  handshaking could be implemented fairly
easily.

     It would be good if the tty port waited for the FIFO to empty before allowing
  a close, so that I could turn off the channel interrupts at that
     time.  It can be done.

OpenBSD     3.6                        January      12,      2002