Common error message during static verification of UPF

Anusha_2016

1. UPF supply unconnected: This error occurs if supply net is created in the power intent using ’create_supply_net’ but is not connected to any driver using ‘connect_supply_net’, i.e., the net is left hanging
2. UPF Supply No state: The possible states of a supply net should be defined to identify different crossovers using ‘add_power_state’ command if it is a supply set. This error occurs if any supply net is defined in the power intent but its state is not mentioned.
3. Unconnected Macro or pad cell power pins: This error is flagged if supply et connections to power pins of macro blocks or pad cells are not mentioned explicitly. If it is the case, then those pins might be connected to the primary power supply of power domain in which these macro blocks are placed by implementation tool. This may lead to improper functioning of the desion.
4. Unconstrained port: The voltage levels of signal pins of a block are usually associated with block’s primary power and ground supplies. If there input and output ports should be associated with some other supplies, then it should be explicitly mentioned in UPF files using ‘set_related _supply_net’ or ‘set_port_attribute’ command. Otherwise, they might be wrongly associated by implementation tool and might result in removal or placement of level shifter cells. This error or warning is flagged if a top level port’s associated supply is not mentioned.
5. Missing Isolation or level shifter strategy: The isolation and level shifter strategies ared defined at RTL stage itself in UPF file. Based on the power states of nets connected to source and sink domains, if an isolation or level shifter strategy is to be defined between that source and sink but it is not, then no isolation or level shifter cells will be placed resulting in malfunctioning of the design. The missing of isolation and level shifter strategies are detected by the tool and an error is flagged.
6. Unconnected level shifter power pins: If level shifter power pins are not connected to any supply net sing ‘connect_supply_net’ command, this error or warning occurs. In that case, these power pins are either left hanging or connected to default power supply of power domain in which there cells are present. This might result in malfunctioning of the cell.