SD card module with Teensy 4.1

Wiring for the SD card module (full size, SPI) on the Teensy 4.1 (MIMXRT1062DVJ6B, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

SD card module pin	Role	Teensy 4.1 pin	Notes
GND	Ground	G
3V3	Power	3V	Use 3V3 or 5V, not both
5V	Not wired to the board	not connected	Alternative 5 V input through the on-board regulator
CS	SPI chip select	10 (GPIO_B0_00)
MOSI	SPI MOSI	11 (GPIO_B0_02)
SCK	SPI clock	13 (GPIO_B0_03)
MISO	SPI MISO	12 (GPIO_B0_01)
GND2	Ground	G

Check before you power it on

Supply: 3.3 V from the 3V pin.

Test code (Arduino)

// Library: SD (built in)
#include <SPI.h>
#include <SD.h>

void setup() {
  Serial.begin(115200);
  if (!SD.begin(10)) {
    Serial.println("No card: check wiring, the card format (FAT32) and power");
    return;
  }
  File f = SD.open("/test.txt", FILE_WRITE);
  f.println("Hello from the board");
  f.close();
  Serial.println("Wrote test.txt");
}

void loop() {}

Arduino board: teensy:avr:teensy41. Press the white program button once if the upload waits for the board.

Questions

Which Teensy 4.1 pins do I use for the SD card module?

GND → G, 3V3 → 3V, CS → 10 (GPIO_B0_00), MOSI → 11 (GPIO_B0_02), SCK → 13 (GPIO_B0_03), MISO → 12 (GPIO_B0_01), GND2 → G.

Does the SD card module work with the Teensy 4.1 at 3.3 V?

Yes: the SD card module runs at 3.3-5 V and the Teensy 4.1 uses 3.3 V signals, so no level shifting is needed.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full Teensy 4.1 pinout · SD card module (full size, SPI): all pins and data

The SD card module on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico

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