Method for driving values to DC adjusted/untimed nets to identify timing problems
First Claim
1. A method, in a data processing device, for verifying an operation of untimed net segments of an integrated circuit design, comprising:
- receiving the integrated circuit design;
receiving a “
don'"'"'t care”
(DC) adjusted list that identifies net segments that do not need to adhere to timing requirements;
comparing entries in the DC adjusted list to a netlist for the integrated circuit design to identify an untimed net segment based on a match of a net segment in the DC adjusted list with a net in the netlist for the integrated circuit design;
driving a value along a pathway to the at least one untimed net segment;
monitoring an output state value from the untimed net segment;
verifying an operation of the untimed net segment of the integrated circuit design based on the collected output value from the untimed net segment;
determining whether there is a violation in the operation of the untimed net segment;
determining whether downstream logic in the integrated circuit design uses the output value; and
removing the untimed net segment from the DC adjusted list if there is a violation in the operation of the untimed net segment and downstream logic in the integrated circuit design does not use the output value.
4 Assignments
0 Petitions
Accused Products
Abstract
A method for driving values to “don'"'"'t care” (DC) adjusted/untimed nets of an integrated circuit design to thereby identify timing problems are provided. The system and method may be utilized, for example, with logical built-in self test (LBIST) testing of an integrated circuit in which the DC adjusted (dcadj) nets for normal functional mode of the integrated circuit may not be DC adjusted for LBIST mode. By using the system and method, timing related problems associated with DC adjusted/untimed nets can be made apparent either by using simulation or semi-formal/formal analysis. For example, with regard to DC adjusted/untimed nets, the system and method may identify any violations of these nets with regard to maintaining their DC adjusted values. Such identification of violations of DC adjusted/untimed nets may be made without interfering with the static timing analysis of timed nets.
38 Citations
18 Claims
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1. A method, in a data processing device, for verifying an operation of untimed net segments of an integrated circuit design, comprising:
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receiving the integrated circuit design; receiving a “
don'"'"'t care”
(DC) adjusted list that identifies net segments that do not need to adhere to timing requirements;comparing entries in the DC adjusted list to a netlist for the integrated circuit design to identify an untimed net segment based on a match of a net segment in the DC adjusted list with a net in the netlist for the integrated circuit design; driving a value along a pathway to the at least one untimed net segment; monitoring an output state value from the untimed net segment; verifying an operation of the untimed net segment of the integrated circuit design based on the collected output value from the untimed net segment; determining whether there is a violation in the operation of the untimed net segment; determining whether downstream logic in the integrated circuit design uses the output value; and removing the untimed net segment from the DC adjusted list if there is a violation in the operation of the untimed net segment and downstream logic in the integrated circuit design does not use the output value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method, in a data processing device, for verifying an operation of untimed net segments of an integrated circuit design, comprising:
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receiving the integrated circuit design; receiving a “
don'"'"'t care”
(DC) adjusted list that identifies net segments that do not need to adhere to timing requirements;comparing entries in the DC adjusted list to a netlist for the integrated circuit design to identify an untimed net segment based on a match of a net segment in the DC adjusted list with a net in the netlist for the integrated circuit design; converting the untimed net segment to single source and single sink net; identifying a source latch that feeds the untimed net segment; identifying, in the integrated circuit design, a path to the untimed net segment from its source latch; replicating, in the integrated circuit design, the identified path to form a replicated path; driving a value to the untimed net segment along the identified path and the replicated path; monitoring an output state value from the untimed net segment; and verifying an operation of the untimed net segment of the integrated circuit design based on the collected output value from the untimed net segment; determining whether there is a violation in the operation of the untimed net segment; determining whether downstream logic in the integrated circuit design uses the output value; and removing the untimed net segment from the DC adjusted list if there is a violation in the operation of the untimed net segment and downstream logic in the integrated circuit design does not use the output value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification