This is the command alliance-ocp that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
- Standard Cell Placer
ocp [options] netlist outputname
ocp is an automatic place tool for standard-cells.
The netlist file describes the input net-list.
ocp supports a hierarchical net-list. In this case the net-list is flattened by the placer
according to the catalog file. The net-list format can be : structural VHDL, EDIF, or
ALLIANCE internal format according to the environment variable MBK_IN_LO.
The file containing the placed block will have the name outputname. This name is not
optionnal and must always be present. The output format is defined by the environment
Optional cells placement file
A user defined pre-placement can be specified, thanks to a placement file.
The optional placement file must be given by the user. It must have an extension that
denotes the format defined by the environment variable MBK_IN_PH.
Optional connectors placement
The placement of connectors can be also specified.
There are four ways to place connectors in a physical view :
-partial <NAME> pre-placed connectors defined by the user can be provided through the pre-
placement file. In that case, automatic connector placement is impossible.
-c option will automatically place the connectors randomly. The auto placement will set
connectors on each side of the abutment box.
-ring option will automatically place the connectors for the ring pad placement tool. The
placement is random but only on the north and south side unless the -ioc <NAME> option is
given, in which case the constraints given in the <NAME>.ioc file will be respected, but
with layers suitable for ring.
-ioc <NAME> option will place connectors as specified by the <NAME>.ioc given file.
It is possible to force the free area of the physical view.
The -margin <MARGIN> option allow to set The amount of free area added in percentage of
the cells area.
The resulting area will be equal to CELL_AREA * (1 + <MARGIN>).
By default, the margin value is 0.2 (20%)
-eqmargin option will distribute equitably the margin between cells. By default, the
biggest possible number of 2-pitch tie cells is inserted. This is done to have the best
well and bulk polarity.
Number of rows
-rows <NR> option forces the design to be placed in <NR> rows.
The abutment box's width is automatically generated.
This option won't be used if a defined placement file is given.
-v set the verbose mode on
-gnuplot option allow to generate automatically gnuplot files, for editing statistics
The IOC format is based on Cadence input-output connectors placement description.
The description is composed of 5 possibles sections: TOP(), BOTTOM(), LEFT(), RIGHT(), and
In each section except IGNORE(), there are placed IOs.
In the IGNORE() section, the IOs are ignored by OCP.
In every section, the IO syntax could be:
for pin: (IOPIN iopinName.0 );
for space: SPACE value;
The capital words are keywords. orientation is not required.
The value is the space (number of pitches) between the IO above and the IO below it.
TOP ( # IOs are ordered from left to right
(IOPIN b(3).0 );
(IOPIN cin.0 );
(IOPIN ck.0 );
(IOPIN cout.0 );
BOTTOM ( # IOs are ordered from left to right
(IOPIN i(3).0 );
(IOPIN i(4).0 );
(IOPIN i(5).0 );
(IOPIN i(6).0 );
IGNORE ( # IOs are ignored(not placed) by IO Placer
ocp uses the environment variables MBK_VDD and MBK_VSS to know the name of the power
signals vdd and vss.
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