How to set CS pin on Beetle BLE/Bluno Beetle to Adafruit SD Card Breakout - Initialization Failed! Hi I have a Beetle BLE (https://www.dfrobot.com/wiki/index.php/Bluno_Beetle_SKU:DFR0339) and I am trying to connect an Adafruit MicroSD card breakout board+ (https://www.adafruit.com/product/254) via SPI connections. I am trying the following code, but I am having trouble selecting the CS pin using D4 since the Beetle has no D10. Does anyone know if I am selecting D4 correctly, while keeping pin 10 as an output. I keep getting initialization failed! My setup is on the ICSP 6 pin configuration:

5V --> 5V

MISO --> DO

SCK -->CLK

GND --> GND

MOSI --> DI

D4 --> CS

RST is left out

Here is my code:

#include &lt;SPI.h&gt;

#include &lt;SD.h&gt;

File myFile;

void setup()
{
  Serial.begin(9600);
  Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin 
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
  // or the SD library functions will not work. 
//   pinMode(4, OUTPUT);
   pinMode(10, OUTPUT);
//   digitalWrite(4, HIGH); // Add this line

  if (!SD.begin(4)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.

  myFile = SD.open("test.txt", FILE_WRITE);

  // if the file opened okay, write to it:
  if (myFile) {
    Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
  // close the file:
    myFile.close();
    Serial.println("done.");
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }
}

void loop()
{
  // nothing happens after setup
}
The ICSP header labels on the Wiki page are wrong. In the schematic here the ICSP header has the same pinout as other Arduinos. The legend doesn't match the picture on the Wiki page but is true:     


ICSP1: Atmega 328P
ICSP2: CC2540


The ICSP header is the inner one. Is right on the pictures.
At pin 1 on board the corner of the white square around pins is skewed. The pins are from left to right first row Eeset, CLK, MISO, second row Ground, MOSI, 5 V.

pdf schematic for the board