UPF File

UPF stands for “Unified Power Format”. This file is mainly associated with low-power (Multi-power domains) designs and important for optimizing power consumption in modern electronic devices. This file describes the power intent or power management specifications for low-power designs. This UPF file was implemented using TCL Programming. The following flow diagram gives the steps of UPF file:

UPF file version
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Create supply ports
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Create supply nets
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Connect supply nets and supply ports
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Create supply sets
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Create power domains
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Create power switch rule and map the rule to the power switch cell
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Define power states
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Create retention cell rule and map the rule to retention cell
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Create isolation cell rule and map the rule to the isolation cell
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Create level shifter cell rule and map the rule to the level shifter cell

Before diving into each step, let me tell you one fact about UPF (Unified Power Format) file. UPF is cannot be supported by all EDA tool. It only supported by the Synopsys and Mentor tools. But coming to cadence, it can support CPF (Common Power Format) file. Purpose of both UPF and CPF file are almost same. But in the later years, cadence announced that it can support IEEE 1801 format, which is similar to the UPF file.

UPF Commands

• upf_version <version> : This command defines UPF version.
• set_design_top <design name> : Name of the design define using this command.
• create_supply_port <port name>: This command creates the supply ports.
• create_supply_net <net name>: This command creates the supply nets.
• connect_supply_net <net name> – <port name>: To connect the supply nets and ports.
• create_supply_set <set name> -function {power <power name>} -function {ground <ground name>}: This command creates supply sets.
• create_power_domain <domain name> -include_scope -supply {primary <supply set name>}: This create a default power domain. Here, -include_scope indicates this power domain is default.
• create_power_domain <domain name> -elements <module name> -supply {primary <supply set name>} -supply {specified domain supply set name}: This creates power domain with associate it with a supply set.
• create_power_switch: This creates the power switch rule for each power domain.
• map_power_switch: The power switch rule has to map to related power switch cell in the library.
• add_port_state: This defines the operating conditions. And adds state information to a supply port.
• create_pst: This creates Power State Table and list of supply nets to be used in the add_pst_state.
• add_pst_state: It defines the legal combinations of states, that is, those combinations of states that can exist at the same time during the operation of the design.
• set_retention: The retention rule has to create using this command.
• map_retention_cell: This command maps the retention rule to the related retention cell in the library.
• set_level_shifter: The level shifter rule has to create using this command.
• map_level_shifter_cell: This command maps the level shifter rule to the related level shifter cell in the library.
• set_isolation: The isolation rule has to create using this command.
• map_isolation_cell: This command maps the isolation rule to the related isolation cell in the library.