Today came in a new batch of PCBs from DirtyPCB.com, of which one is a new revision of the BlackMagicProbe. This revision is almost the same except it has a polyfuse in its powersupply to the target, a dedicated voltage regulator instead of P-FET, its programming header on the 90 degree on the side and a jumper for entering DFU mode. All this goodness is contained in less 5×2 cm PCB space, so quite a bit of PCB estate is left for other purposes and I used panelizing in EAGLE to try another brainfart of mine.

In most DIY projects where pogo pins are used people solder them directly to a wire or pad on a PCB. Despite it looks like it is the way to go, it isn’t. Pogo pins tend to wear out relative quickly as they are only rated for a couple of hundred ‘compressions’, also solder can sip into the pin and ruin its spring. The proper way is to use matched sockets, which allows quickly replacing wore down pogo pins. They come in two variations: wirewrap (or PTH) and directly solder able. The socket has a also a ‘bulge’ to keep it secure in place.

By using the excess PCB estate I created some common ICSP/debug arrangements: 2×5 (JTAG), 1×5 (Microchip ICSP) and 1×4 (serial, SWD). The holes have a diameter of 1.7mm, which is a bit thicker then the pin diameter, but smaller then the bulge. The pogopin is fixed to the PCBs by blobs of hotglue. Optional some heatshrink tube can be applied.

I got my pins in directly from a manufacturer in Shenzhen but you can get them per 100 from here. Also the mechanical drawing are provided there.