| # Power nets | 
 | set ::power_nets $::env(_VDD_NET_NAME) | 
 | set ::ground_nets $::env(_GND_NET_NAME) | 
 |  | 
 | pdngen::specify_grid stdcell { | 
 |     name grid | 
 | 	core_ring { | 
 | 		met5 {width $::env(_WIDTH) spacing $::env(_SPACING) core_offset $::env(_H_OFFSET)} | 
 | 		met4 {width $::env(_WIDTH) spacing $::env(_SPACING) core_offset $::env(_V_OFFSET)} | 
 | 	} | 
 | 	rails { | 
 | 	} | 
 |     straps { | 
 | 	    met4 {width $::env(_WIDTH) pitch $::env(_V_PITCH) offset $::env(_V_PDN_OFFSET)} | 
 | 	    met5 {width $::env(_WIDTH) pitch $::env(_H_PITCH) offset $::env(_H_PDN_OFFSET)} | 
 |     } | 
 |     connect {{met4 met5}} | 
 | } | 
 |  | 
 | pdngen::specify_grid macro { | 
 | 	instance "obs_core_obs" | 
 |     power_pins $::env(_VDD_NET_NAME) | 
 |     ground_pins $::env(_GND_NET_NAME) | 
 |     blockages "li1 met1 met2 met3 met4 met5" | 
 |     straps {  | 
 |     }  | 
 |     connect {} | 
 | } | 
 |  | 
 |  | 
 | pdngen::specify_grid macro { | 
 |     power_pins $::env(_VDD_NET_NAME) | 
 |     ground_pins $::env(_GND_NET_NAME) | 
 |     blockages "" | 
 |     straps {  | 
 |     }  | 
 |     connect {} | 
 | } | 
 |  | 
 | set ::halo 0 | 
 |  | 
 | # POWER or GROUND #Std. cell rails starting with power or ground rails at the bottom of the core area | 
 | set ::rails_start_with "POWER" ; | 
 |  | 
 | # POWER or GROUND #Upper metal stripes starting with power or ground rails at the left/bottom of the core area | 
 | set ::stripes_start_with "POWER" ; | 
 |  |