Interactive Manual Routing in TCL

[bent93]

Hello,

I am trying to apply some manual routing to my design. To learn how to do that, I went through Lab 3 of "Vivado Design Suite Tutorial: Implementation (UG986)". The basic methodology is to enter assign routing mode, break up a path and then recompose it by starting from either end and selecting neighbouring paths. At the end, a path is generated and placed in an XDC file for future use.

Is there any way to perform this flow interactively in TCL? What I would need is a command to break a path, list neighbouring nodes and then select one of them until I have a complete path to my destination. Is that possible?

I found this thread from someone that aspires to do a similar thing, but the solution was to do it once in the GUI and then use the generated path. I would like to generate that path in TCL instead of the GUI.

Thanks for any help or pointers

[surajc]

Hi @bent93,

In order to manually route a net from one site to another site, you first need to fix the placement of the cells the net connects.

which can be done using following commands

set_property is_bel_fixed 1 [get_cells {<source_cell>  <destination_cell>}]
set_property is_loc_fixed 1 [get_cells { <source_cell>  <destination_cell> }]

and then you need to open the device view and get the names of the nodes of the site pins. ( you can do this by selecting a site pin and looking in site properties window ). Once you have all the node names use the following command to assign routing

set_property fixed_route { { <node_name_of_site_pin_on_Which_source_cell_is_placed> <intermediate_node_1> <intermediate_node_2> <intermediate_node_n> <node_name_of_site_pin_on_Which_desitnation_cell_is_placed> } } [get_nets <net_name>]

however this is very tedious which is why vivado has Assign Routing Mode inbuilt which uses GUI and interactive method to do the same task.

--Suraj

[bent93]

Hi @surajc, thanks a lot for your reply.

So there is no way to get the names of the nodes of the site pins in TCL?

Is there any other way I can get to that information? Like is there a database for each fpga that I could use to query routing options?

[surajc · Accepted solution]

Hi @bent93 

please have a look at the get_nodes command from UG835

https://www.xilinx.com/support/documentation/sw_manuals/xilinx2019_1/ug835-vivado-tcl-commands.pdf#page=812

--Suraj

[bent93]

That looks promising, thank you so much!