iscd(7)                          DG/UX 5.4.2                         iscd(7)


NAME
       iscd - Integrated Synchronous Chip Driver

SYNOPSIS
       iscd()

DESCRIPTION
       The iscd driver provides the interface to the integrated synchronous
       hardware (a Signetics 68562 DUSCC).  To support the integrated
       synchronous chip driver you must specify iscd() in the system
       configuration file prior to building the DG/UX kernel.

       The format of the iscd system file entry is as follows:

           iscd()

       For more information concerning device configuration, refer to
       Writing a Device Driver for the DG/UX System.

       For the iscd system file entry, three i-nodes in /dev are created as
       the iscd devices are configured: one clone device, and one for each
       I/O port.

       The iscd creates a clone device i-node with the format iscds00.  This
       00 is to maintain compatibility with the other synchronous drivers.
       The clone device can be used for line management functions such as
       statistics manipulation and line configuration.  I/O messages will
       not be processed on a clone device.  The clone device supports
       multiple opens.  The number of opens supported by the clone device is
       a system file parameter.

       The /dev i-nodes used for I/O have the format iscd00u, where u is the
       unit number.  The unit number specifies a specific communications
       channel on the DUSCC.  A value of 0 for u corresponds to the Comm-A
       port, and a value of 1 for u corresponds to the Comm-B port.  Line
       management functions that are allowed on the clone device are also
       allowed on these I/O devices.  Each I/O device supports only one open
       at a time.

       In conjunction with the iscd system file entries, the following
       system file variables are used by the iscd at configuration time.

       System file parameter           Alias Name
       cfiscdtotalclones            ISCDCLONES
       cfiscdreceivebuffers         ISCDRXBUFF
       cfiscdoversizebuffers        ISCDOVBUFF
       cfiscdoversizebuffersize    ISCDOVSIZE
       cfiscdlegendflushretries    ISCDLFRETRY

       cfiscdtotalclones specifies the number of allowable clone opens
       for the clone device.

       cfiscdreceivebuffers specifies the number of STREAMS buffers that
       will be pre-allocated for receiving frames.



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iscd(7)                          DG/UX 5.4.2                         iscd(7)


       cfiscdoversizedbuffers specifies the number of STREAMS buffers
       that will be pre-allocated to use for receiving frames that are
       larger than the configured maximum frame size.

       cfiscdoversizedbuffersize specifies the size in bytes of the
       STREAMS buffers that will be pre-allocated to use for receiving
       frames that are larger than the configured maximum frame size.

       cfiscdlegendflushretries specifies the maximum number of times we
       will check that a flush of the DMA has occurred on receipt of a
       frame.

EXAMPLES
       The following is the system file entry:

       iscd()

       If this entry appears in the system file, the iscd creates the
       following i-node entries at configuration time:

       /dev/iscds00   iscd clone device (for line management)
       /dev/iscd000   iscd port A I/O device (for port A I/O)
       /dev/iscd001   iscd port B I/O device (for port B I/O)

SEE ALSO
       ssid(7), vsxb(7), wanadm(1M).

NOTES
       Baud Rates
              The iscd driver supports the following internally generated
              baud rates:

               1200    2400    4800
               9600   19200   38400
              48000   56000   64000

              In addition to the internal baud rates listed above, the iscd
              will accept any external clock data rate up to 64000 bps.

       Buffer Restrictions
              The maximum frame size can not exceed 64000 bytes.
















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