CPF - two primary_power_nets for one power domain (different virtual power domains for different voltage sites of an IP block)

Hi there!

Cadence innovus 16.13  | CPF v1.1 | ST Microelectronic 28nm

I am working on a Multiple power domain design. I have got a PLL block as an IP (no access inside the block of course) and this PLL block according to its vendor datasheet consists of two separate domain:

1. an internal analog part with 1.8V
2. an internal digital part with 0.9

I need to put this whole IP block in one domain for instance PD_PLL. However, since there are two separate analog and digital parts in the IP block, no update_power_domain  -primary_power_net can be used for the whole PD_PLL. Therefore, I used two virtual power domain in my CPF file. This is an excerpt of the whole lines of CPF file:

• define_library_set -name lib_0_80V_12t_lvt_lp_tc -libraries AND ALL OTHER LIBRARY SETS
• define_level_shifter_cell ALL NECESSARY CELLS

• create_power_nets  -nets {VDD_LEVELSHIFT}   -voltage 0.80:1.20
• create_power_nets  -nets {AVDD_PLL}         -voltage 1.8
• create_power_nets  -nets {DVDD_PLL}         -voltage 0.9
• AND ALL OTHER NETS ...

• create_power_domain   -name PD_PLL             -instances ...
• create_power_domain   -name PD_LEVELSHIFT      -instances ...
  

• # Creating virtual power Domain for analog and digital parts of PLL to assign primary power_nets
• create_power_domain -name PD_DPLL
• create_power_domain -name PD_APLL

• create_level_shifter_rule     -name lsr_pad_pllout -pins {ChipTop_1/LevelShiftDomain_1/INFOUT*} -from PD_DPLL -to PD_LEVELSHIFT
• update_level_shifter_rules    -names lsr_pad_pllout     -location to

• create_nominal_condition   -name cond_high_lvt_lp_12t_0v80   -voltage 0.80
• update_nominal_condition   -name cond_high_lvt_lp_12t_0v80   -library_set "lib_0_80V_12t_lvt_lp_tc"
• and for all other voltages
  

• create_power_mode -name PM_0v80 -domain_conditions {PD_SRAM0@cond_high_lvt_lp_12t_0v80 \
• create_global_connection

• create_global_connection -domain PD_PLL          -net AVDD_PLL          -pins avddpll1v8
• create_global_connection -domain PD_PLL          -net AGND_PLL          -pins agndpll1v8
• create_global_connection -domain PD_PLL          -net DVDD_PLL          -pins dvddpll0v9
• create_global_connection -domain PD_PLL          -net DGND_PLL          -pins dgndpll0v9

• update_power_domain -name PD_DEFAULT      -primary_power_net VDD_DEFAULT     -primary_ground_net GND   -pmos_bias_net VDDS_LVT -nmos_bias_net GNDS_LVT
• # update virtual power domains for PLL
• update_power_domain -name PD_DPLL -primary_power_net DVDD_PLL -primary_ground_net DGND_PLL
• update_power_domain -name PD_APLL -primary_power_net AVDD_PLL -primary_ground_net AGND_PLL

The problem happens when I want to transfer signals from 0.90V section to a levelshifter for voltage upscaling. after commiting the CPF file, the following come from CPF commit generated report:

**WARN: (IMPCPF-2204):    Cannot get the primary power net for the power domain PD_PLL, using first power net DVDD_PLL specified in connections as primary power net.

**ERROR: (IMPCPF-261):    line 735: create_level_shifter_rule lsr_pad_pllout: Cannot insert a level shifter instance to drive a net from power domain PD_DPLL to power domain PD_LEVELSHIFT, with a valid location in power domain to. The valid cell for this rule was not found. Ensure that the location specified in update_level_shifter_rule is identical to the 'valid_location' option specified by define_level_shifter command.

How I can assign two separate power domains to different voltage sites in an IP block and later assign them their respective primary_power_nets and avoiding any problem like the above which doesnt let the tool to add the necessary level shifter cells in PD_LEVELSHIFT for upscaling the signals coming from 0.90V part.

Regards