Hello,
I’m trying to tune a trace on a PCB to reach a total length of, for example, 65 mm. If there is a test point along the trace, while trying to tune the total trace length, it should consider the pad where the net starts and ends, but it doesn’t tune beyond the test point pad. Do you think this is a bug? Normally, if the total trace length encounters a pull-up resistor pad, pull-down resistor pad, or test point pad along the way, why doesn’t it tune according to the total trace length and instead stops at the pads along the trace?
How would KiCad be able to distinguish the imortance of an IC from a pullup resistor? For KiCad, it’s all just pads and footprints, and KiCad follows simple rules. Currently it is not implemented, but apparently it is known, and there are plans to fix it. For a testpoint the workaround is simple. Just place the testpoint after the length tuning is done. Some more details in the thread below.
The last thing you want on a timing critical track is a spur. The highest speed PCIE and USB tracks might even be affected by a large test pad impedance discontinuity
Yes, i found a similar problem pairing a differential track for USB.
My PCB has 2 turns of 90 degree to the CCW, a long travel (30mm) and 1 turn of 90 degree to CW.
After each turn, i have a small differential displacement, so the right is measure what is the difference after each curve and fix before to continue the track. But i dont find how read partial length difference
