Can't get SD to initialize

[TheLardos]

Hi,

I'm trying to get my SD card module initialized, but no matter what I try, I just can't get it to work.

I've written a simple code:

#include <SPI.h>
#include <SD.h>

// Definition der Pins
const int chipSelect = 1; // GP1 (CSn)

void setup() {
  Serial.begin(9600);
  while (!Serial) {
  }

  SPI.setRX(0); // GP0 als MISO
  SPI.setTX(3); // GP3 als MOSI
  SPI.setSCK(2); // GP2 als SCK
  SPI.begin();

  Serial.print("InitializeSD-Card...");
  if (!SD.begin(chipSelect)) {
    Serial.println("SD-card couldn't be initialized.");
    return;
  }
  Serial.println("successful");
}

void loop() {
}

I am using a Pimoroni tiny rp2040 (here is a photo of the pinout:

)
I appreciate any help I can get on this.

Thanks in advance!
Luca

[earlephilhower]

Moved to a discussion since it's not a core issue.

Double check your wiring (i.e. GPx is not the same as your PCB pins) and ensure you're running a 3.3V capable adapter. Some of those boards have onboard 5V regulators and I/O buffers (SD is 3.3V, but old Arduino boards were 5V) which could make them incompatible with the 3.3V pico. You really want a board with nothing active on it. I've even successfully used a microSD-to-fill-SD adapter with wires tacked on to the contacts, directly connected to the Pico GPIOs.

[TheLardos]

Thank you for your quick reply. I tested your method of directly soldering to an microSD-to-fill-SD adapter and this actually worked! So it has something to do with the module that I used..

Thank you for your help and sorry for putting this topic in the wrong category!

[earlephilhower]

No worries, glad to hear it's running.

For more "professional" use, I've had success with boards like this from the usual suspects:

It's basically a straight-through wiring with only some Rs and Cs to better meet the SD specs for slew/etc.

[TheLardos]

That's exactly what I just ordered! Thank you for your support!