On the underside of the TinyFPGA BX, there are two connections, which I refer to as “belly connectors” for lack of better term. It is completely undocumented how to make use of these connections.
I have surface-mount IDC pin header strips which mate with these pads; however, trying to solder to them is a right nightmare as the pins just keep moving. There’s no guarantee of alignment. I tried to make my own jig to hold the strips in place, but again, to no avail – now there’s insufficient room to even just tack them in place with the fine-point soldering tip I currently have.
So, how does one make use of these pins, without the expense and long-term reliability issues of pogo-pins?