
                      Chips and Technologies
           DS82C235 SCATEMM.SYS EMM Driver Documentation




I.   Introduction:

This document describes the MS-DOS device driver SCATEMM.SYS, which
in conjunction with a Chips and Technologies 82C235 "SCAT" chip
or 82C236 "SCATsx" chip provides support for LIM EMS 4.0



II.  Device Driver Installation

This EMS driver is supplied as a device driver that can be loaded
at DOS boot time.  The user is required to edit the CONFIG.SYS file
so that it contains a line in the form of:

          DEVICE = d:[path]\SCATEMM.SYS [options]

where d: and [path] represent the drive and path where the driver
is located.

The driver is designed so that, under normal circumstances, it does
not need any command line options in order to give satisfactory
performance.  However, command line options are provided so that
the driver may be tailored to a user's specific needs.

Before installing the driver, you should run your system SETUP and
make sure to set aside sufficient memory for your needs.  This
memory should be designated as expanded memory.


III. Command Line Parameters

The following command line parameters are available for
knowledgeable users who wish to tailor the driver for their own
requirements.  Option names may be shortened to their first two
characters.  Options should be separated by one or more spaces.
Spaces are optional before and after the '-' and '=' symbols.


 FRAME = aaaa
      Specifies the page frame address (the address of the 64K
      segment through which expanded memory is mapped.  "aaaa"
      must be either D000 or E000.  Specifying FRAME will
      override the automatic choice of page frame by the
      driver.


 EXCLUDE = xxxx [- cccc]
      Specifies an area of memory which should not be under
      the control of the SCATEMM.SYS driver. "xxxx" and "cccc"
      specify the address or range of addresses of memory to
      be excluded and should be in multiples of 16K (i.e. end
      in 00).  EXCLUDE may be used several times on the driver
      command line to exclude multiple blocks of memory,
      though at least 64K of memory should remain above 640K
      (A000).  The driver will find all RAM/ROM in the range
      D000 - EFFF, and will adjust for them.



 INCLUDE = xxxx [- cccc]
      Specifies memory to be included under the control of the
      SCATEMM.SYS driver.  Parameters are similar to EXCLUDE
      above.



 HANDLES = hhh
      Specifies the number of handles and names available.
      "hhh" must be in the range of 16 to 255, with the
      default being 64.



 IOADDR = aaa
      Overrides the default base I/O address at which the
      "SCAT/SCATsx" Chip should be configured.  aaa must be either
      208 or 218.

 DIAGS = xxx
      Specifies whether EMS memory diagnostics are performed during
      initialization of the driver.  "xxx" must be ON or OFF.  The
      default is OFF.


IV.  Error Messages


 "Initialization Error. Memory Manager not Installed"
      This is a generic error message that is accompanied by
      another error message.  This means that for some reason
      (given by the other error message) the EMM driver could
      not be installed correctly.



 "Cannot detect mapping hardware"
      The EMM driver could not find a Chips 82C235 "SCAT" chip
      or 82C236 "SCATsx" chip in the system.  Make sure that your
      EMS is enabled. This error may indicate that you have the
      wrong driver for your system.


 "Problems encountered with memory initialization"
      The EMM driver could not set up the page frame
      correctly.  Make sure that there is at least one
      contiguous 64K segment of unused memory space above 640K
      (A000).



 "Interrupt 67 Vector already allocated"
      Some other driver has already allocated the EMS
      interrupt vector.  Remove all other EMS drivers from
      your CONFIG.SYS file.



 "I/O address specified is not one of the permitted values"
      The EMS mapper I/O address you indicated using the
      IOADDR command line option is an invalid address.  Make
      sure that it is either 208 or 218.



 "An equals (=) sign was expected"
      One of your SCATEMM.SYS command line options was not
      immediately followed by an equals '=' sign.  Check your
      CONFIG.SYS file to make sure the SCATEMM.SYS command
      line is formatted correctly.



 "Invalid HEX number or not divisible by 16"
      One of your INCLUDE or EXCLUDE "xxxx" command line
      arguments is incorrect.  Each "xxxx" argument for these
      options must be divisible by 16 (ending in 00).



 "Number of handles invalid or out range"
      The value you specified for the HANDLES command line
      option is invalid.  Make sure it is a decimal number
      between 16 and 255.



 "Invalid Page Frame Address"
      The page frame address you specified is invalid.  The
      page frame must start at either D000 or E000.



 "No working memory can be found. EMM aborted"
      The driver cannot find any memory set aside as expanded
      memory.  Make sure to run your system SETUP, and set
      aside some memory for expanded memory.



 "Unrecognized command/option in command line"
      The string displayed after this error message was found
      to be invalid.  Edit your CONFIG.SYS to make sure this
      invalid option is corrected.



 "End address is less than starting address"
      One of the "cccc" addresses specified for either the
      INCLUDE or EXCLUDE options is less than the "xxxx" value
      for that option.



 "The command line is incomplete"
      Options are incomplete on the SCATEMM.SYS command line.
      Make sure that all command line options are correctly
      formatted.



 "Problems encountered in setting default page frame address"
      The default page frame address found in your system CMOS
      is invalid.  This is not a fatal error, if this occurs
      the driver will use the default base address.  Make sure
      to run your system SETUP and make sure that your EMS
      base address is valid.



 "Decimal number input overflow error"
      The number of handles specified is an invalid number.
      Edit your CONFIG.SYS and make sure that the parameter
      for HANDLES is correctly formatted.

 "Error EMS I/O not enabled"
      EMS has not been enabled on the Chips 82C235 "SCAT" or
      82C236 "SCATsx" ChipSet. Run your system SETUP and make sure EMS
      has been enabled.

 "The EMS hardware is disabled or not functional"
      This is a generic error message that is accompanied
      by another error message.  This means that for some
      reason (given by the other error message) the EMS
      hardware is not operating properly.
