magic/doc/html/property.html

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<TITLE>Magic-8.3 Command Reference</TITLE>
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<H2>property</H2>
<HR>
Attach a "property" (string key and value pair) to the edit cell
<HR>
<H3>Usage:</H3>
<BLOCKQUOTE>
<B>property</B> [<I>key</I> [<I>value</I>]] <BR><BR>
<BLOCKQUOTE>
where <I>key</I> and <I>value</I> are any text strings.
</BLOCKQUOTE>
</BLOCKQUOTE>
<H3>Summary:</H3>
<BLOCKQUOTE>
The <B>property</B> command implements a general-purpose method
of attaching information to a cell definition. Except for a
few properties known to the <B>lef</B>, <B>extract</B>, and
<B>gds</B> commands (q.v.), properties have no inherent meaning
to magic but may be used with other programs or scripts to add
additional information about a cell definition. <P>
With no arguments, all properties of the current edit cell are
listed. With only the <I>key</I> argument, the value associated
with the key is returned. With both arguments, the string
<I>value</I> is associated with the string <I>key</I> as a
property of the cell. If <I>key</I> is an existing key, then
its original value will be overwritten.
</BLOCKQUOTE>
<BLOCKQUOTE>
Property names reserved by and used by magic:
<DL>
<DT> <B>GDS_FILE</B>
<DD> The value is the name of a GDS file which contains the mask
data for the cell. The cell is then effectively an abstract
view, because its contents are in the GDS file and do not
necessarily match what is displayed (although they might).
<DT> <B>GDS_START</B>
<DD> If a <B>GDS_FILE</B> is defined, then this value indicates the
byte position of the start of mask data for this cell definition
in the file. If set to value <B>0</B>, then the file will be
searched for the data bounds.
<DT> <B>GDS_END</B>
<DD> If a <B>GDS_FILE</B> is defined, then this value indicates the
byte position of the end of mask data for this cell definition
in the file. If <B>GDS_START</B> is set to <B>0</B>, then this
property may be omitted.
<DT> <B>LEFview</B>
<DD> If set to <B>TRUE</B>, this cell is an abstract view such as that
obtained from a LEF macro, and should not be used for extraction
or for writing mask data (unless <B>GDS_FILE</B> is defined).
<DT> <B>LEFproperties</B>
<DD> If the file was read from a LEF macro, then this property corresponds
to the LEF <B>PROPERTY</B> block values. All values from the block
are contatenated into the single property string.
<DT> <B>LEFsymmetry</B>
<DD> If the file was read from a LEF macro, then this property corresponds
to the macro's <B>SYMMETRY</B> value.
<DT> <B>LEFclass</B>
<DD> If the file was read from a LEF macro, then this property corresponds
to the macro's <B>CLASS</B> value.
<DT> <B>LEFsite</B>
<DD> If the file was read from a LEF macro, then this property corresponds
to the macro's <B>SITE</B> value.
<DT> <B>CIFhier</B>
<DD> If defined, then this cell will be written to CIF or GDS
output with hierachical processing regardless of the settings of
the command options "cif *hier write disable" and "cif *array write
disable". That allows those commands to be used to avoid
time-consuming and unnecessary hierarchical processing of a top-level
chip assembly with mostly correct-by-design components (such as a
digital standard cell layout) while preserving necessary hierarchical
processing on blocks (such as analog circuits) that need them.
<DT> <B>FIXED_BBOX</B>
<DD> This property value is a space-separated list of four integer values
corresponding to the abutment box of the cell, in magic's internal
units. The abutment box is automatically read from LEF files, but
may be defined for any file and can be used for placement alignment.
<DT> <B>OBS_BBOX</B>
<DD> This property value is a space-sparated list of four integer values
corresponding to a bounding box to be used when generating a LEF
file abstract view of a cell. The area inside the bounding box
will be entirely covered in obstruction layers (unless cut-outs
are required to accommodate pins). Any set-back applied by the
"lef write -hide <value>" option will be applied to this obstruction
box.
<DT> <B>flatten</B>
<DD> This property is used in conjunction with the "flatten -doproperty"
command option and marks the cell for flattening. Cells without
this property defined will not be flattened.
<DT> <B>device</B>
<DD> This property declares that the cell is a device or contains a
single device that is not a known extractable device defined in
the technology file. In the first case, the device to be extracted
is a subcircuit and the name of the device is the same as the name
of the cell. In this case, the property value should begin with
"<B>primitive</B>". This may be followed by any parameters
associated with the device that need to be output in the netlist;
e.g., "<B>primitive nf=4</B>. When the cell is recast as a
primitive device, it is necessary for the port order in the cell
to match the port order of the device as it must appear in the
output netlist. In the second case, the device to be extracted
is either a low-level component type (not a subcircuit), or is a
subcircuit with a different name than the cell. In that case, the
value string should be the text of the line as it should appear
in a "<B>device</B>" line in the output <TT>.ext</TT> file when the
cell is extracted. That includes the names of all ports and any
parameters to be output. As the output device is defined inside
the subcircuit of the cell in which it is defined, the ports may
be reordered between the subcircuit and the instantiation of the
device. The use of either form of the <B>device</B> property
precludes the generation of parasitics associated with the cell.
All parasitics are assumed to be included in the device model.
<DT> <B>parameter</B>
<DD> If, when an instance of the cell's subcircuit is generated in the
output netlist, the instance should be passed one or more
parameters, then those parameter <I>key</I><B>=</B><I>value</I>
pairs (as a single, space-separated string) should be defined as
the value to the <B>parameter</B> property.
<DT> <B>MASKHINTS_</B><I>type</I>
<DD> The value is a string of consecutive sets of four integer values,
each set representing the bounding box of a rectangle defining
the area of CIF type <I>type</I>, in magic's internal units.
This indicates that magic will
always generate mask layer <I>type</I> in the specified rectangle
area when writing GDS or CIF output. <I>type</I> may be a templayer,
such that <I>type</I> could be defined as the absence of a mask layer,
for example.
</DL>
</BLOCKQUOTE>
<H3>Implementation Notes:</H3>
<BLOCKQUOTE>
<B>property</B> is implemented as a built-in command in <B>magic</B>.
The property structure itself is implemented as a hash table in
the cell definition structure.
</BLOCKQUOTE>
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<P><I>Last updated:</I> March 7, 2020 at 1:06pm <P>
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