Hardware Question regarding board to board mezzanine connector
I'm working on making my own custom extension board for a project and I'm having issues with the 3v3 power on pins 1 & 3 of the mezzanine connector on the bottom of the Spresense main board.
When connecting the Spresense main board to my custom board I've verified that I am not receiving power on my 3v3 rail. I have extensively tested continuity from the inside of the female mezzanine connector on pins 1&3 on my custom board to end of the 3v3 traces that run to my peripheral devices.
I have also confirmed that the 3v3 pins on the male end of the mezzanine connector (on the main Spresense board) are outputting 3v3. This was verified by individually probing with an o-scope as well as attaching the main Spresense board to the official Sony extension board. The extension board operates as expected.
The interesting thing is that when I run a separate wire from my custom board's 3v3 rail to the 3v3 output pin on the main board (between pins D22 & D23 next to the 1.8v output pin) my custom extension board behaves as expected and communication over the SPI and I2C channels through the mezzanine connector are functional.
At this point I'm concerned about the connection on pins 1&3 of my mezzanine connector and wanted to verify that there isn't something I haven't considered or if there are any additional debugging procedures I might try.