Common Power Format

• CPF (Common Power Format)
• CPF is power intent as similar as UPF which we have seen earlier. 
• CPF structure is like UPF, only difference is UPF is handled by Synopsys VC static/dynamic tool, whereas CPF is handled only by Cadence’s CLP tool.

• Below is Low Power flow for CPF: 

CPF Definition Arch

• Commands of CPF and UPF are much more similar only difference is in few syntax, will try to write CPF for below design block:

  

  Example

• Commands of CPF and UPF are much more similar only difference is in few syntax, let’s have glance of CPF commands below:
  
  
  #Definition of top domain
  set_design top
  #Define the top power domain
  create_power_domain –name pdTOP –default
  #Define pdA
       create_power_domain -name pdA \
                                            -instances {uA uC} \
                                            -shoutoff_condition {!uPCM/pso[0]}
  #Define PSO- pdB when pso is low
       create_power_domain  -name pdB \
                                             -instances {uB } \
                                             -shoutoff_condition {!uPCM/pso[1]}
   
• Design with multiple power domain and have power shutoff condition along with isolation cell definition. All outputs of pdB isolated high on rising edge of uPCM/iso  
  
  
       set highpin { uB/en1 uB/en2 }
       create_isolation_rule -name ir1 \
                                          -from pdB \
                                          -isolation_condition {uPCM/iso} 
                                          -isolation_output high \
                                          -pins “$highpin”
  
  

  

  PD with ISO strategy in CPF

• Design with multiple power domain, let’s have look at Level sifters:
  #Level shifter definition:
   create_level_shifter_rule –name lsr1 -to {pdB} -from {pdA}
   create_level_shifter_rule –name lsr2 -to {pdA} -from {pdB}
   create_level_shifter_rule –name lsr3 -to {pdtop} -from {pdB}
   create_level_shifter_rule –name lsr4 -to {pdA} -from {pdtop}

  

  ISO+LS in CPF

• Retention strategy definition in CPF:
  
  
  
   #retention strategy rule:
   #Defined state retention strategy: state stored on falling edge of restore[0] and restored           rising edge.
   #Note: if –save is not specified, it is logical NOT of the –restore signal       vice-versa 
  
  
   set srpgList {uB/reg1 uB/reg2}
   create_state_retention_rule -name sr1\
                                                -restore_edge {uPCM/restore[1]}
  .         

• Power modes definition in CPF:
  
  
  #Top is always high, pdA/pdB can be medium or low.
  create_nominal_condition –name high –voltage 1.2
  create_nominal_condition –name medium –voltage 1.0
  create_nominal_condition –name low –voltage 0.8
  create_nominal_condition –name off –voltage 0
  
  
  #Define the modes:
   create_power_mode  -name PM1 \
                                     -domain_condition {pdTOP@high pdA@medium pdB@medium}
   create_power_mode -name PM2 \
                                     -domain_condition {pdTOP@high pdA@low pdB@low}
   create_power_mode -name PM3 \
                                    -domain_condition {pdTOP@high pdA@low pdB@off}
    end_design
    
• Power shut off sequence:

  

  Power Down Seq

• Power up sequence:

Power-Up Seq