Hi Cathy, Thanks for the help. I think the Valor New Product Introduction(NPI) community would be most appropriate. Would be great if you could move it.
Thanks for replying, Donal. Too funny -- when I saw "ICT," my mind jumped to the Interconnect Table (ICT) in Xpedition Designer when you obviously meant In-Circuit Test. Hopefully, someone here in the NPI community can help you.
There is a testability report created from Valor Process Preparation that calculates test probe density based on the ICT probes that have been placed. It allows the user to specify an area and then a limit on the maximum number of probes that can be allowed in that area. Any times that the number of probes found exceeds that number it is output to the testability report. It is based on each side separately and does not take in to account the components placed on the opposite side.
This request can be in the context of pressure but that can easily be complicated due to the fixture design and hold down gate hence why we implemented this in a simple manner to detect high number of test probes.
I am referring to the test probes, aka nails or needles, and not the test points on the board. Probes can be placed on other targets apart from test points and it is the force of the test probes that is important, unused test point locations are not relevant.
Generally we only place test probes on dedicated testpads or connector pins.
The current rules work very well for finding the high testpoint density areas, however there can be very many of these on a layout. It is only the ones with a lack of access on the opposite side I am interested in.
For example, there were 399 red violations (tp_density) reported on our layout but only 12 of these pointed to the high stress area (verified using strain gauges) where the component footprint was high on the opposite side. Just changing the red limit did not find this area on the board. It found the densest area which did not have high comp density on the other side.
Adding to Mark's comment, I think the best you can get at this time is overall percentage of coverage. This can be accomplished by running the Test Point automation in Xpedition and calculating based on the test points not placed.
This sounds like it would make a great IDEA for you to post on the IDEAs site.