ADDER X-SC Bedienungsanleitung PDF herunterladen (Seite 53)

1.23. RING 53

of two behavioral descriptions.

1.23 Ring

Ring is the pad ring router of Alliance. It is used with the following command (it has no options).

% ring source result [stat]

We will apply ring to our multiplexer design, but ﬁrst we will edit a .rin ﬁle describing the orientation of its

inputs and outputs. T his ﬁle is as follows.

north(q,c)

south(b,a)

east(p_vssb)

west(p_vddb)

width(vss 50 vdd 80)

The above ﬁle is not enough to use ring. We must also provide a structural ﬁle of our design that includes the

pads.

1.24 S2R

S2R (Symbolic to Layout) is the tool in Alliance that let us translate our symbolic design to a real one. For

this, S2R uses the technology ﬁle deﬁned by the RDS TECHNO NAME environment variable. If we provide

an appropiate technology ﬁle the output of S2R will be a layout ﬁle that can be given to a foundry for the

fabrication of the design. During the design with Alliance we can also place and route the pads of the core

using Ring. However, real pads are speciﬁc to a foundry and must be designed to ﬁt to those of Alliance. One

thing that must be taken into account is that the pads in Alliance have their abutment box at the lower left

coordinate. We must also check that the foundry cells have an abutment box size multiple of the symbolic grid

step used in Alliance. We use S2R with the following command.

s2r [-tc1rv] source [result]

The options available in S2R are shown in Table 1.23. We determine the type of the output ﬁle of S2R setting

Table 1.23: Options Available for the S2R Tool.

Option Description

-t

Suppress the denotching phase. s2r performs gap ﬁlling, denotching in order to avoid DRC

errors. This operation is time consuming. It is mandatory for the foundry but not really

useful for capacitance evaluation.

-c

Deletes connectors and node names at all hierarchy level. Theses objects link the physical

view and the logical view of a chip. If simulation is to be done after physical mapping,

connectors must appear, so that the extractors and simulators can use them. This must

not be used when preparing a ﬁnal layout for the foundry. For the factory, the top level

connectors are forbidden, since they do not represent any physical reality.

-1

Creates the top level cell with the instances as black boxes. This may be useful for hierar-

chical extractors, since the ﬁle size may be greatly reduced.

-r

Does not replace black boxes. Cells ﬂagged with the G attribute in the catal(5) ﬁle will not

be replaced by their equivalent layout loaded from disk.

-v

Verbose mode on.

the appropiate ﬁle type through the RDS OUT environment variable. The default type is cif, but we can also

set it to gds. The catalog ﬁle name used in pad substitution is set by the MBK CATAL NAME variable. The

variable RDS IN is used to deﬁne the format of the cells used in the s ubstitution process. The format of the

symbolic layout is determined by the MBK IN PH variable.

1.25 SCAPIN

The SCAPIN (SCAn Path INsertion) tool is used in Alliance to insert a scan path in the netlist of a design.

scapin [-VRB] [-P file] infile pathfile outfile

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