A clever zero-cost alternative I've seen some manufacturers use is a 1xN PTH footprint with every other hole offset slightly (~20 mil) to the side. The misalign

A clever zero-cost alternative I've seen some manufacturers use is a 1xN PTH footprint with every other hole offset slightly (~20 mil) to the side. The misalignment is just enough to make a straight pin header get stuck in the holes. There's an example of this on Digilent's Arty development board, at the top of the board between JB and JC: https://digilent.com/shop/arty-a7-100t-artix-7-fpga-development-board/ https://digilent.com/shop/arty-a7-100t-artix-7-fpga-developm...