400 lines
15 KiB
ReStructuredText
400 lines
15 KiB
ReStructuredText
.. -*- Mode: rst -*-
|
|
.. include:: ../etc/definitions.rst
|
|
.. include:: ./definitions.rst
|
|
|
|
|
|
6. Making a hierarchical Cell -- Netlist
|
|
========================================
|
|
|
|
To illustrate the topic, we will build the netlist of a fulladder from
|
|
standard cell.
|
|
|
|
|fulladder_1|
|
|
|
|
|
|
6.1 Creating an Instance_
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Creating an Instance_ is straigthforward, the constructor needs only three
|
|
parameters:
|
|
|
|
#. The Cell_ **into which** the instance is to be created.
|
|
#. The name of the instance.
|
|
#. The **master cell**, the Cell_ model it refers to. The master cell
|
|
will be part of the hierarchical level just below the ``fulladder``
|
|
cell.
|
|
|
|
.. note:: Do not confuse the cell the instance is create into (``fulladder``)
|
|
and the cells it refers to (the *master cell* ``xr2_x2``).
|
|
|
|
.. code-block:: Python
|
|
|
|
af = AllianceFramework.get()
|
|
xr2_x2 = af.getCell( 'xr2_x1', Catalog.State.Views )
|
|
|
|
fulladder = af.createCell( 'fulladder' )
|
|
xr2_1 = Instance.create( fulladder, 'xr2_1', xr2_x2 )
|
|
|
|
|
|
6.2 Creating Nets and connecting to Instances
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
An Instance_ has one Plug_ for each external net of the *master cell*.
|
|
The plug allows to create a **logical** connection bewteen a Net_ of
|
|
``fulladder`` and a net from an Instance_ *master cell*.
|
|
|
|
A plug is somewhat equivalent to an *instance terminal* in other
|
|
well known databases.
|
|
|
|
Therefore, a plug is related to two nets:
|
|
|
|
#. The net of the *master cell* it is linked to. Obviously that
|
|
net cannot be changed. You can access the master net with the
|
|
function ``plug.getMasterNet()``.
|
|
|
|
#. The net of ``fulladder`` the plug is connected to. This can
|
|
be set, it is how we build the netlist. To set the net, use
|
|
the function ``plug.setNet( net )``. If the argument is ``None``,
|
|
the plug is *disconnected*.
|
|
|
|
To find the plug of an instance associated to a given net in
|
|
the *master cell*, use ``instance.getPlug( masterNet )``.
|
|
The ``masterNet`` argument being an object of class net (not
|
|
its name).
|
|
|
|
Building the :cb:`a` net of ``fulladder``:
|
|
|
|
.. code-block:: Python
|
|
|
|
a = Net.create( fulladder, "a" )
|
|
a.setExternal( True )
|
|
xr2_1.getPlug( xr2_x2.getNet("i0") ).setNet( a )
|
|
a2_1 .getPlug( a2_x2.getNet("i0") ).setNet( a )
|
|
|
|
|
|
.. note:: **Limitation of Hurricane Netlists.** There is no explicit
|
|
terminal object in the |Hurricane| database. Plugs are
|
|
generated *on the fly* for each *external net* of the
|
|
instance. One important consequence is that a *net*
|
|
cannot appear on the interface as two differently named
|
|
terminals (sometimes referred as *weekly connected*
|
|
terminals). There is a strict bijection between external
|
|
nets and plugs.
|
|
|
|
While it may be restrictive, it enforces cleaner designs
|
|
and make it possible for the HyperNet_ concept/class.
|
|
|
|
|
|
6.3 Power supplies special case
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
For supplies, it may be tedious to connect the Plugs_ of each cell one by one
|
|
(and create a lot of unneeded objects). To avoid that, we may use **Named
|
|
connections**. If a signal in ``fulladder`` is set to *global*, then it will
|
|
be considered as connected to any signal with the *same name* and *global* in
|
|
the master cell of the instances.
|
|
|
|
.. code-block:: Python
|
|
|
|
vdd = Net.create( fulladder, "vdd" )
|
|
vdd.setExternal( True )
|
|
vdd.setGlobal ( True ) # Will be connected to all the instances.
|
|
|
|
|
|
6.4 Creating the physical view of a Cell netlist
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Even if loaded in the viewer, an Instance will not be displayed
|
|
until it is placed.
|
|
|
|
|
|
6.4.1 Transformation
|
|
--------------------
|
|
|
|
To place an Instance, we apply a Transformation_ to the coordinate system
|
|
of the *master cell*. A transformation is composed of two operations:
|
|
|
|
#. An Orientation_, which can be a symmetry or a rotation (or a combination
|
|
of those two). The Orientation **is applied first** to the coordinate
|
|
system of the *master cell*. The complete list of Orientation and their
|
|
codes are given on the Orientation documentation page.
|
|
|
|
#. A **Translation**, applied in second. Translation are represented by
|
|
Points_.
|
|
|
|
The transformation is a change of coordinate system, be aware that if the
|
|
abutment box lower left corner of the *master* cell is **not** at ``(0,0)``
|
|
the result of the Transformation may not be what you expect. To simplify
|
|
the computation of the transformation of an instance, always place the
|
|
lower left corner of the abutment box at ``(0,0)``
|
|
|
|
|
|
6.4.2 Placing an Instance
|
|
-------------------------
|
|
|
|
Assuming that we want to place the cells of the ``fulladder`` into two rows,
|
|
that the abutment box lower left corner is at ``(0,0)`` (same for the
|
|
``xr2_x2`` *master cell* layout). Here is the code to place the ``xr2_1``
|
|
instance to left of the second row.
|
|
|
|
Setting the translation on an Instance_ is not enough to make it be displayed,
|
|
we also must set its *placement status* to ``Instance.PlacementStatus.PLACED``.
|
|
|
|
.. code-block:: Python
|
|
|
|
xr2_1.setTransformation( Transformation( DbU.fromLambda( 0.0)
|
|
, DbU.fromLambda(100.0)
|
|
, Transformation.Orientation.MY ) )
|
|
xr2_1.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
|
|
|
|
6.4.3 Nets -- From Plugs to RoutingPads
|
|
---------------------------------------
|
|
|
|
As was stated before, Plugs_ represent a logical connection between two
|
|
levels of hierarchy. To make the physical connection to the *master net*
|
|
in the instance, we now must create, in the ``fulladder``, a special
|
|
component which is a kind of *reference* to a component of the
|
|
*master net* (in the master cell).
|
|
|
|
The so called *special component* is a RoutingPad_.
|
|
|
|
The ``RoutingPad`` can be considered as an equivalent to ``pin`` in other
|
|
well known databases.
|
|
|
|
.. code-block:: Python
|
|
|
|
rp = RoutingPad.create( a
|
|
, Occurrence( xr2_1.getPlug( xr2_x2.getNet("i0")) )
|
|
, RoutingPad.BiggestArea )
|
|
|
|
For the second parameter, we must pass an Occurrence_. Occurrence objects will
|
|
be explained in detail later, for now, let say that we must construct the
|
|
Occurrence object with one parameter : the Plug_ for which we want to create a
|
|
physical connection.
|
|
|
|
The RoutingPad_ ``rp`` will be a component of the ``a`` net.
|
|
|
|
The third argument ask the constructor of the RoutingPad_ to select in the
|
|
master net, the component which has the biggest area.
|
|
|
|
.. note:: **Component selection.** Not all the components of a net can be
|
|
selected for connection through a RoutingPad_. The candidates must
|
|
have been flagged with the NetExternalComponents_ class.
|
|
|
|
See `3.6.3 Creating a Component`_.
|
|
|
|
|
|
6.4.4 Nets -- Regular wiring
|
|
----------------------------
|
|
|
|
After the creation of the RoutingPads_, the wiring is to be created with
|
|
ordinary layout components (Horizontal_, Vertical_ and Contact_ possibly
|
|
articulated). Here is the complete code for net ``a``. We made an articulated
|
|
layout where contacts are created over RoutingPads_ then segments over
|
|
contacts.
|
|
|
|
.. code-block:: Python
|
|
|
|
# Build wiring for a.
|
|
# Create RoutingPads first.
|
|
rp1 = RoutingPad.create( a
|
|
, Occurrence( xr2_1.getPlug( xr2_x2.getNet("i0")) )
|
|
, RoutingPad.BiggestArea )
|
|
rp2 = RoutingPad.create( a
|
|
, Occurrence( a2_1.getPlug( a2_x2.getNet("i0")) )
|
|
, RoutingPad.BiggestArea )
|
|
|
|
# Then regular wiring.
|
|
contact1 = Contact.create( rp1, via12, toDbU( 0.0), toDbU(-15.0) )
|
|
contact2 = Contact.create( rp2, via12, toDbU( 0.0), toDbU( 10.0) )
|
|
turn = Contact.create( a , via23, toDbU(10.0), toDbU( 35.0) )
|
|
Horizontal.create( contact2, turn , metal2, toDbU(35.0), toDbU(2.0) )
|
|
Vertical .create( turn , contact1 , metal3, toDbU(10.0), toDbU(2.0) )
|
|
|
|
|
|
.. note:: In order to better see the layout of the wiring only, open the
|
|
``Controller`` and in the :fboxtt:`Filter` tab, uncheck
|
|
:fboxtt:`Process Terminal Cells`.
|
|
|
|
|
|
6.5 The Complete Example File
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
The example file ``fulladder.py`` can be found in the ``share/doc/coriolis2/examples/scripts/``
|
|
directory (under the the root of the |Coriolis| installation).
|
|
|
|
.. code-block:: Python
|
|
|
|
#!/usr/bin/python
|
|
|
|
import sys
|
|
from Hurricane import *
|
|
from CRL import *
|
|
|
|
|
|
def toDbU ( l ): return DbU.fromLambda(l)
|
|
|
|
|
|
def doBreak ( level, message ):
|
|
UpdateSession.close()
|
|
Breakpoint.stop( level, message )
|
|
UpdateSession.open()
|
|
|
|
|
|
def buildFulladder ( editor ):
|
|
|
|
# Get the Framework and all the master cells.
|
|
af = AllianceFramework.get()
|
|
xr2_x2 = af.getCell( 'xr2_x1', Catalog.State.Views )
|
|
a2_x2 = af.getCell( 'a2_x2' , Catalog.State.Views )
|
|
o2_x2 = af.getCell( 'o2_x2' , Catalog.State.Views )
|
|
|
|
UpdateSession.open()
|
|
|
|
fulladder = af.createCell( 'fulladder' )
|
|
fulladder.setAbutmentBox( Box( toDbU(0.0), toDbU(0.0), toDbU(90.0), toDbU(100.0) ) )
|
|
|
|
if editor:
|
|
UpdateSession.close()
|
|
editor.setCell( fulladder )
|
|
editor.fit()
|
|
UpdateSession.open()
|
|
|
|
# Create Instances.
|
|
a2_1 = Instance.create( fulladder, 'a2_1', a2_x2 )
|
|
a2_2 = Instance.create( fulladder, 'a2_2', a2_x2 )
|
|
xr2_1 = Instance.create( fulladder, 'xr2_1', xr2_x2 )
|
|
xr2_2 = Instance.create( fulladder, 'xr2_2', xr2_x2 )
|
|
o2_1 = Instance.create( fulladder, 'o2_1', o2_x2 )
|
|
|
|
# Create Nets.
|
|
vss = Net.create( fulladder, "vss" )
|
|
vss.setExternal( True )
|
|
vss.setGlobal ( True )
|
|
|
|
vdd = Net.create( fulladder, "vdd" )
|
|
vdd.setExternal( True )
|
|
vdd.setGlobal ( True )
|
|
|
|
cin = Net.create( fulladder, "cin" )
|
|
cin.setExternal( True )
|
|
xr2_2.getPlug( xr2_x2.getNet('i0') ).setNet( cin )
|
|
a2_2 .getPlug( a2_x2.getNet('i0') ).setNet( cin )
|
|
|
|
a = Net.create( fulladder, 'a' )
|
|
a.setExternal( True )
|
|
xr2_1.getPlug( xr2_x2.getNet('i0') ).setNet( a )
|
|
a2_1 .getPlug( a2_x2.getNet('i0') ).setNet( a )
|
|
|
|
b = Net.create( fulladder, 'b' )
|
|
b.setExternal( True )
|
|
xr2_1.getPlug( xr2_x2.getNet('i1') ).setNet( b )
|
|
a2_1 .getPlug( a2_x2.getNet('i1') ).setNet( b )
|
|
|
|
sout_1 = Net.create( fulladder, 'sout_1' )
|
|
xr2_1.getPlug( xr2_x2.getNet('q' ) ).setNet( sout_1 )
|
|
xr2_2.getPlug( xr2_x2.getNet('i1') ).setNet( sout_1 )
|
|
a2_2 .getPlug( a2_x2.getNet('i1') ).setNet( sout_1 )
|
|
|
|
carry_1 = Net.create( fulladder, 'carry_1' )
|
|
a2_1.getPlug( a2_x2.getNet('q' ) ).setNet( carry_1 )
|
|
o2_1.getPlug( o2_x2.getNet('i1') ).setNet( carry_1 )
|
|
|
|
carry_2 = Net.create( fulladder, 'carry_2' )
|
|
a2_2.getPlug( a2_x2.getNet('q' ) ).setNet( carry_2 )
|
|
o2_1.getPlug( o2_x2.getNet('i0') ).setNet( carry_2 )
|
|
|
|
sout = Net.create( fulladder, 'sout' )
|
|
sout.setExternal( True )
|
|
xr2_2.getPlug( xr2_x2.getNet('q') ).setNet( sout )
|
|
|
|
cout = Net.create( fulladder, 'cout' )
|
|
cout.setExternal( True )
|
|
o2_1.getPlug( o2_x2.getNet('q') ).setNet( cout )
|
|
|
|
# Instances placement.
|
|
a2_1.setTransformation( Transformation( toDbU(0.0)
|
|
, toDbU(0.0)
|
|
, Transformation.Orientation.ID ) )
|
|
a2_1.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Placed a2_1' )
|
|
|
|
xr2_1.setTransformation( Transformation( toDbU( 0.0)
|
|
, toDbU(100.0)
|
|
, Transformation.Orientation.MY ) )
|
|
xr2_1.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Placed xr2_1' )
|
|
|
|
a2_2.setTransformation( Transformation( toDbU(25.0)
|
|
, toDbU( 0.0)
|
|
, Transformation.Orientation.ID ) )
|
|
a2_2.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Placed a2_2' )
|
|
|
|
xr2_2.setTransformation( Transformation( toDbU( 45.0)
|
|
, toDbU(100.0)
|
|
, Transformation.Orientation.MY ) )
|
|
xr2_2.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Placed xr2_2' )
|
|
|
|
o2_1.setTransformation( Transformation( toDbU(65.0)
|
|
, toDbU( 0.0)
|
|
, Transformation.Orientation.ID ) )
|
|
o2_1.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Placed o2_1' )
|
|
|
|
# Add filler cells.
|
|
tie_x0 = af.getCell( 'tie_x0', Catalog.State.Views )
|
|
rowend_x0 = af.getCell( 'rowend_x0', Catalog.State.Views )
|
|
filler_1 = Instance.create( fulladder, 'filler_1', tie_x0 )
|
|
filler_2 = Instance.create( fulladder, 'filler_2', rowend_x0 )
|
|
|
|
filler_1.setTransformation( Transformation( toDbU(50.0)
|
|
, toDbU( 0.0)
|
|
, Transformation.Orientation.ID ) )
|
|
filler_1.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
|
|
filler_2.setTransformation( Transformation( toDbU(60.0)
|
|
, toDbU( 0.0)
|
|
, Transformation.Orientation.ID ) )
|
|
filler_2.setPlacementStatus( Instance.PlacementStatus.PLACED )
|
|
doBreak( 1, 'Filler cell placeds' )
|
|
|
|
# Getting the layers.
|
|
technology = DataBase.getDB().getTechnology()
|
|
metal2 = technology.getLayer( "METAL2" )
|
|
metal3 = technology.getLayer( "METAL3" )
|
|
via12 = technology.getLayer( "VIA12" )
|
|
via23 = technology.getLayer( "VIA23" )
|
|
|
|
# Build wiring for a.
|
|
# Create RoutingPads first.
|
|
rp1 = RoutingPad.create( a
|
|
, Occurrence( xr2_1.getPlug( xr2_x2.getNet("i0")) )
|
|
, RoutingPad.BiggestArea )
|
|
rp2 = RoutingPad.create( a
|
|
, Occurrence( a2_1.getPlug( a2_x2.getNet("i0")) )
|
|
, RoutingPad.BiggestArea )
|
|
|
|
# Then regular wiring.
|
|
contact1 = Contact.create( rp1, via12, toDbU( 0.0), toDbU(-15.0) )
|
|
contact2 = Contact.create( rp2, via12, toDbU( 0.0), toDbU( 10.0) )
|
|
turn = Contact.create( a , via23, toDbU(10.0), toDbU( 35.0) )
|
|
Horizontal.create( contact2, turn , metal2, toDbU(35.0), toDbU(2.0) )
|
|
Vertical .create( turn , contact1 , metal3, toDbU(10.0), toDbU(2.0) )
|
|
|
|
UpdateSession.close()
|
|
|
|
af.saveCell( fulladder, Catalog.State.Views )
|
|
return
|
|
|
|
|
|
def ScriptMain ( **kw ):
|
|
editor = None
|
|
if kw.has_key('editor') and kw['editor']:
|
|
editor = kw['editor']
|
|
|
|
buildFulladder( editor )
|
|
return True
|