Move _zero to special nets

[Blebowski]

Hi,
related to previous question, when I proceed to detailed routing, I get:

detailed_route -bottom_routing_layer ME2 -top_routing_layer ME5

[ERROR DRT-0305] Net zero_ of signal type GROUND is not routable by TritonRoute. Move to special nets.
[ERROR GUI-0070] DRT-0305

Before, I created my voltage domain and power-grid like so:

add_global_connection -net VDD -pin_pattern {^VDD$} -power
add_global_connection -net VSS -pin_pattern {^VSS$} -ground

set_voltage_domain -name VDD_1V2 -power VDD -ground VSS

define_pdn_grid -name "Core"


add_pdn_stripe -layer ME1 -followpins -width 0.2

add_pdn_ring -grid "Core" -layers {ME4 ME5} -widths 4.5 -spacings 1.0 -core_offsets {0 0} -add_connect

add_pdn_stripe -layer ME4 -width 1.5 -pitch 20 -offset 0 -extend_to_core_ring
add_pdn_stripe -layer ME5 -width 1.5 -pitch 20 -offset 0 -extend_to_core_ring

add_pdn_connect -layers {ME1 ME4}
add_pdn_connect -layers {ME1 ME5}

pdngen

I thought that "moving zero_ to special nets" can be accomplished by something like:

assign_ground_net -domain VDD_1V2 -net [get_nets zero_]

But that throws me:

[ERROR ODB-0335] group does not exist
[ERROR GUI-0070] ODB-0335

Can you help me out here?
Probably I am just doing something super-stupid...

[maliberty]

Generally _zero is avoided by using hilomap in yosys. If you are not using yosys then I suggest using insert_tiecells

[Blebowski]

Thanks :)