General • MicroSD card connection to Pico 2W

Hello everyone,

I'd like to insert a MicroSD card reader into my PCB project using a Raspberry Pi Pico 2W. I've already identified the connector I'll use: DM3AT-SF-PEJM5. Here's its pin configuration:
And here is my PCB schematic:
MicroSD cards require 3.3V. That's great, so it will obviously be connected to the Pico's regulated 3.3V, so there's no need for a 5V adapter like with Arduinos.
But one question remains: Are pull-up resistors (or any other component) necessary/essential? I see a lot of ready-made modules that contain them:
I heard that the Pico already has internal pull-ups. What does this mean, and is it sufficient?

And could you explain how the detection card system works, and what is required to use it correctly (an additional resistor?)?

Thank you in advance for your answers.

Statistics: Posted by Zebananos — Sat Aug 23, 2025 4:18 pm

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