I'm about to connect a micro SD card to a ESP32-S3. Because there might be no space to pull the card I'm going to use one of the spring loaded and locking connectors.
When looking at the available connectors at LCSC of that type and restricting the selection to 1.8..2.0mm and gold plating, there are still 33 products to choose from. All look about the same. Is there a standardized footprint for those connectors, so I can created a PCB that works for most of them? If so, does it matter what connector to choose?
How does the CD pin work? I guess it is shorted to either the GND pin or the metal cover plate when the card is in or out. What of this?
I might want to add an activity LED indication for the card. Is there any signal pin that I can use? In SPI mode, the CS pin should work but does this also work as desired in 4-bit mode?
I also read somewhere that the interface (don't know whether 1- or 4-bit) requires pull-ups. I believe for SPI this should not be necessary as long as a floating MISO is not an issue for the CPU. But what about 4-bit mode?
And finally a question regarding all SMD connectors (eg. USB): Sometimes under mechanical stress (accidents), the copper layer can get ripped of the PCB. Does it help to put some vias under or close to the mounting pads? If so, what hole diameter is best?
Of course the pads should be kept as large as possible.