SD Card Guidance

[nolansneeder]

Hello! I’m wanting to add an SD card slot into a PCB that I’m designing and I’m a little bit confused about what is required. Just for clarification, if I’m already operating on 3.3V I don’t need a level shifter right? I’ve also seen some people use EMI filter chips like these:

https://www.onsemi.com/products/isol...SAAEgJ07vD_BwE

Are they necessary? Or can I just hook up the SPI connections directly to my microcontroller? Thanks!

[brtaylor]

With everything on 3.3V, I've just wired from the SD to the microcontroller. Make sure you have enough current capacity for the SD - they can be a bit power hungry.

[UhClem]

Are they necessary?

It depends on the environment. If you are putting SD cards into the socket only at a nice safe ESD protected workbench, then no. If you are going to let any idiot do it anywhere, then yes, you need the ESD protection.

[nolansneeder]

That makes sense. I’m putting it on a data logger for a model rocket but I think it should be fine to get wired straight up at least for prototyping!

[UhClem]

I used a Teensy to build a rocket data logger.

[nolansneeder]

That’s sweet! I’ll have to give it a read! I’ve built a couple through hole prototypes of mine but I’m interested in learning PCB design so I’m going to give that a shot for my next revision!