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Introduction

                        LASI to CALMA Conversion


  LASI drawings are not ver useful if they cannot be transformed into the
  more commonly used CAD system formats. The most common is CALMA Stream
  Format. Although CALMA drawing systems for IC's have become somewhat
  obsolete, the data format survives, and newer CAD systems such as CADENCE
  or MENTOR can usually convert it. LASI can be converted to CALMA Stream
  Format (CSF) exactly, and from CSF with some limitations.

  LASI has a drawing structure that is very similar to the CALMA drawing
  system, with the exception that LASI has box objects and is more limited
  in its data capacity and cell nesting depth. In LASI, cells are similar
  to CALMA structures, except that a definite rank is attached to a cell.
  Also in LASI there are no boundaries, instead there are zero width paths
  called poly. LASI drawings transform easily into CALMA because a box can
  be made into a boundary, a poly can become a boundary also, a path can
  transform directly into a path, and cells can become structures, partly
  due to their ranked nesting.

  Since LASI drawings are more or less a subset of CALMA, conversion to
  CALMA is easy. More difficult is conversion from CALMA to LASI because
  there are things in CALMA (like arrays, and text) that don't exist in
  LASI (yet). Conversion is possible in most cases if certain restrictions
  are used in the original CALMA drawing (like limiting the structure
  nesting or using only small arrays).
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The Conversion Programs

  The LASI2CSF.EXE program converts a LASI drawing into a binary file which
  is in CALMA Stream Format (CSF). This format is used as the standard for
  preserving and interchanging CALMA drawings. The file generated by
  LASI2CSF.EXE may be sent directly to a CALMA or may be put onto magtape
  if sent to some larger computer that has magtape capability.

  The CSF2TLC.EXE program will read back a CSF file and will construct a
  LASI drawing in TLC form as best as possible. A drawing first done on
  LASI will reconstruct exactly if returned from a CALMA without having
  been modified in some non-compatible way. Drawings made originally on
  CALMA may occasionally convert differently, since LASI presently doesn't
  have such things as datatypes, 64 layers, text or arrays. Rectangular
  CALMA boundaries will be converted to LASI boxes.

  Note that CALMA Stream Files used by LASI2CSF.EXE and CSF2TLC.EXE have
  the extension ".CSF". This is a convention that not always standard. You
  may have to rename you file extensions.
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Running LASI2CSF.EXE

  1. LASI2CSF.EXE must be present in the \LASI directory a "PATH" opened to
  it by execution of the DOS PATH command. (Just as you should do with
  LASI.EXE.) You then run the program while in a drawing directory, usually
  the directory in which you are working.

  2. LASI2CSF will ask for the CALMA drawing name. This is the name that
  the drawing would have on the CALMA.

  3. The program will first ask for the "disk\path" prefix of the directory
  where your LASI cell collection resides. This is the source directory.
  Hit <enter> only for the current directory.

  4. LASI2CSF reads the CELLS.DBD file, the CONSTS.DBD file and the
  FORM.DBD file in the source directory. CONSTS.DBD sets the scales that
  appear in the starting dialog as default values. FORM.DBD will allocate
  memory for the data that the program processes so that memory usage will
  correspond to LASI's usage.

  5. LASI2CSF asks for the "Disk\Path\Name" of the CSF file. The extension
  ".CSF" will be added, so don't include it in the name of the CSF file. If
  a name is unacceptable, it will be asked until an acceptable one is
  given.

  6. LASI2CSF will then ask for scale information. When converting to CALMA
  you must know what physical units you used and how many LASI units per
  physical unit you used in the LASI drawing. You must tell LASI2CSF how
  many CALMA units you want per physical unit. You may default to 1000
  basic units/micron and produce an exact 56-bit floating point
  representation in the CSF file. This seems to be necessary for CADENCE
  conversion.

  7. You will be asked if you want to relocate any LASI layer to CALMA
  layer 0. Sometimes layer 0 is used in CALMA drawings. When converting
  between drawing systems you can use a different LASI layer for what is
  expected to be on CALMA layer 0.

  8. You will be asked for what datatype you want in the CALMA drawing.
  This is an attribute that LASI doesn't have. Usually "0" is sufficient.

  9. When converting to CALMA, you will be given the choice of converting
  only certain cells to CALMA structures. This is useful when you have most
  of your structures already in the CALMA. If you chose to select certain
  cells to be converted, you will be given a choice of also converting the
  lesser cells that are used in the specific cells.
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Running CSF2TLC.EXE

  1. When converting from CALMA to LASI path and filename questions similar
  to those when running LASI2CSF.EXE will be asked.

  2. When converting from CALMA the physical units will automatically be
  microns, but you may specify the LASI basic units.

  3. You will be asked if you want to use the "2048"VAX filter. If the
  binary file has been run through a VAX on magetape, it might contain two
  extra characters at the CSF record boundaries. You can tell CSF2TLC to
  drop two characters every 2048 characters. If errors occur try this
  option.

  4. You will then be asked for the layers and the datatypes to be
  converted. You respond to this question with the notation similar to the
  VIEW, OPEN, etc. commands in LASI, with numbers separated by spaces or
  dashes.  A space separates individual layers and a dash means "include
  all layers between".

  5. You will also be asked to equate CALMA layers to LASI layers. CALMA
  layers 0 and 33-63 may be relocated to any LASI layers 1-32. Layers that
  don't exist in LASI may therefore be translated from CALMA to LASI. Any
  layers not specified that are out of 1-32 will default to layer 32.

      Example: "0=1" relocates CALMA layer 0 to LASI layer 1.


  6. Like LASI2CSF, CSF2TLC request options on just which cells or
  structures you want to be converted. You may name specific cells or
  structures to be converted if a few are wanted. If the named structures
  contain other structures that have not been named, CSF2TLC will find
  these and try to convert them also. You may therefore name only your top
  structure and CSF2TLC will find the rest.

  7. You will be asked if you want CSF2TLC to replace any TLC files that it
  finds already in the directory. Otherwise, CSF2TLC will keep any old TLC
  files that it finds and will only create the new ones that it needs.

  In most questions, the default entry will appear in the parentheses if
  one is available. Hitting <enter> defaults.
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CSF2TLC Operations

  CSF2TLC first scans the CSF file to determine a hierarchy of cells. It
  also tries to convert CALMA structure names to names that are DOS
  acceptable.

  CSF2TLC will search the current directory for the TLC cell file of a cell
  that might not exist as a structure in the CSF file, but still be used in
  other structures in the CSF file. This allows the TLC file of a cell to
  be reconstructed without the lesser cells being present as structures in
  the CSF file. The only requirement is that the TLC files of its lesser
  cells exist already in the drawing directory.

  After the scanning has been done to establish hierarchy and the presence
  of TLC files, a list of the cell names, their rank, the presence of the
  structure in the CSF file, the presence of a TLC file in the directory
  and the structure name is printed.

  If the TLC file is already present it is always retained eventhough the
  structure may exist in the CSF file. To have a new TLC file generated,
  the old TLC file must be deleted from the current directory, or the
  option of replacing all TLC files must be used when running CSF2TLC.

  If the lesser cell exist neither as a structure in the CSF file nor as a
  TLC file in the drawing directory, then the name of the expected cell is
  inserted into the TLC file being made and a warning message is given.
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Possible Problems

  On conversion from CALMA to LASI, if any structures are missing and a TLC
  file is not present, there is no way to tell if the missing structures or
  TLC files contain other missing structures or cells.

  Presently, arrays of objects do not exist in LASI. Therefore, when
  converting from CALMA, CSF2TLC makes arrays by copying cells. This can
  fill the LASI cell capacity if you don't watch out.

  Since LASI2CSF makes boxes in LASI into rectangular boundaries when
  translating to CALMA, and CSF2TLC does the opposite when translating the
  other way, don't expect to be able to edit figures in the same way. For
  example, rectangular boundaries from CALMA cannot have new vertices
  added.

  Some features of CALMA are presently simply ignored, such as text,
  streched components, and nodes.

  If you abort while CSF2TLC is making a TLC file you will probably get an
  incomplete file. Erase it.
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