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tools:netgen [2020/04/29 14:04] rajit |
tools:netgen [2022/06/22 06:53] rajit [Attributes] |
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</ | </ | ||
- | In this example, the transistor gated by '' | + | In this example, the transistor gated by '' |
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- | ===== Subcircuits ===== | ||
- | Placing parts of a production rule set into a sub-circuit simplifies the job of a layout engineer because it is easier to view the netlist at a slightly higher level of abstraction. To support this, we allow the automated generation of one level of hierarchy using the '' | ||
- | prs { | ||
- | ... | ||
- | subckt { | ||
- | a & b -> c- | ||
- | ~a & ~b -> c+ | ||
- | } | ||
- | ... | ||
- | }</ | ||
- | places the C-element in a sub-cell that is automatically generated. The sub-circuit is generated in isolation, so this has a few implications: | ||
- | * State-holding/ | ||
- | * For a state-holding operator, the staticizer is generated within the sub-circuit. This means that if there is an inverter //outside// the sub-circuit, | ||
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Attributes can be attached to a production rule or pass transistor/ | Attributes can be attached to a production rule or pass transistor/ | ||
- | using standard '' | + | using standard '' |
- | on the complete [[designtools: | + | |
* '' | * '' | ||
* '' | * '' | ||
- | * '' | + | * '' |
- | * '' | + | * '' |
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</ | </ | ||
+ | Attributes | ||
+ | |||
+ | ^ Attribute ^ Meaning ^ | ||
+ | | keeper | The production rules for a signal are analyzed to determine if the pull-up and pull-down networks are perfect complements of each other. If they aren' | ||
+ | | comb | If set to 1, uses combinational feedback rather than a weak inverter for the staticizer; if 0, uses a weak inverter instead of combinational feedback | | ||
+ | | iskeeper | used to let prs2net know that the specified production rule is in fact the manually | ||
+ | | isckeeper | used to let prs2net know that the specified production rule is a combinational feedback style keeper circuit. These will be labeled with '' | ||
+ | | loadcap | sets the load capacitance on the output to be a the specified value in pF. This is used to override the default setting specified in the configuration file | | ||
+ | | oresis | sets output resistance for node. This resistance is added in series to the output of the gate, and overrides the default from the prs2net configuration file | | ||
+ | | output | used for pass transistors to force either the source, drain, or both to be labelled as an output. This is useful for the PININFO directive emitted by prs2net. If the value v has bit zero set, then the source is marked as an output node. If v has bit one set, then the drain is marked as an output. By default, a node is considered an input if it does not have a production rule driving it. | | ||
+ | | N_reff | sets the n-stack effective resistance, overriding the default computed by prs2net. This is used to compute strengths of staticizers. The resistance for one transistor is computed as L/W where L and W are the length and width of the transistor respectively. | | ||
+ | | P_reff | same as N_reff, except sets strength of p-stack | | ||