markdown/gh_discussions/Query/3178.md

How to attach/add a new load to a net?

Tool: Design for Test

Subcategory: Usage question

Conversation

fgaray

Hello,

In the DFT tool, I am trying to connect a new created scan_out port at the top level module with the scan out of a scan cell.

The scan out of the cell is previously connected to a functional path, so I am doing something like:

odb::dbNet* functional_net = scan_out_cell->getNet();
scan_out_module->connect(functional_net);

When I print the BTerms of the net, I get both, the scan_out of the module and the previous connected port.

However, I doesn't seems to work if I write the verilog, as I am only seeing it being connected to the original functional port instead of being connected to both of them: scan out and functional port.

Is there something that am I missing?

Thanks, Felipe

maliberty

What is the type of scan_out_module ?

maliberty

An issue with a test case might be better as it doesn't sound like an unusual operation.

fgaray

This was addressed in https://github.com/The-OpenROAD-Project/OpenROAD/issues/3183

However, @maliberty was right in that ticket and we don't really need to punch a new port for scan out, we can just reuse the already existing port. So, we only need to punch a new scan out port if there is funcional logic before scan insertion and there are only ITerms in the net.