Using 2 SPI devices

Hardware:
Arduino Mini: https://www.sparkfun.com/products/11114
Accelerometer - ADXL 345: SparkFun Triple Axis Accelerometer Breakout - ADXL345 - SEN-09836 - SparkFun Electronics
Micro SD Breakout: http://www.adafruit.com/products/254

I’m using SPI for both devices and have test code working for both separately but when i try to use them both, only the SD breakout works.

Wiring: https://learn.adafruit.com/adafruit-micro-sd-breakout-board-card-tutorial/wiring
CS - SD: 10
CD - ACCEL: 9

Code:

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

const int chipSelectSD = 10;
const int chipSelectAC = 9;

File dataFile;

//This is a list of some of the registers available on the ADXL345.
//To learn more about these and the rest of the registers on the ADXL345, read the datasheet!
char POWER_CTL = 0x2D;	//Power Control Register
char DATA_FORMAT = 0x31;
char DATAX0 = 0x32;	//X-Axis Data 0
char DATAX1 = 0x33;	//X-Axis Data 1
char DATAY0 = 0x34;	//Y-Axis Data 0
char DATAY1 = 0x35;	//Y-Axis Data 1
char DATAZ0 = 0x36;	//Z-Axis Data 0
char DATAZ1 = 0x37;	//Z-Axis Data 1

//This buffer will hold values read from the ADXL345 registers.
unsigned char values[10];
//These variables will be used to hold the x,y and z axis accelerometer values.
int x,y,z;

void setup()
{
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  pinMode(A4, INPUT);
  pinMode(A5, INPUT);
  pinMode(A6, INPUT);
  pinMode(A7, INPUT);
  pinMode(chipSelectSD, OUTPUT);
  pinMode(chipSelectAC, OUTPUT);
    
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  SPI.begin();
  //Configure the SPI connection for the ADXL345.
  SPI.setDataMode(SPI_MODE3);
  
  // set CS high for accel
  digitalWrite(chipSelectAC, HIGH);
  
  Serial.print("Initializing SD card...");
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelectSD)) {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    while (1) ;
  }
  Serial.println("card initialized.");
  
  // Open up the file we're going to log to!
  dataFile = SD.open("datalog.txt", FILE_WRITE);
  if (! dataFile) {
    Serial.println("error opening datalog.txt");
    // Wait forever since we cant write data
    while (1) ;
  }
  
  Serial.println("ACCEL INIT.");
  
  //Put the ADXL345 into +/- 4G range by writing the value 0x01 to the DATA_FORMAT register.
  writeRegister(DATA_FORMAT, 0x01);
  //Put the ADXL345 into Measurement Mode by writing 0x08 to the POWER_CTL register.
  writeRegister(POWER_CTL, 0x08);  // Measurement mode 
  Serial.println("ACCEL INIT DONE");
}

void loop()
{
  // make a string for assembling the data to log:
  String dataString = "";

  // read three sensors and append to the string:
  for (int analogPin = 0; analogPin < 8; analogPin++) {
    int sensor = analogRead(analogPin);
    Serial.print(sensor);
    Serial.print(",");
    dataString += String(sensor);
    dataString += ","; 
  }
  
  //Reading 6 bytes of data starting at register DATAX0 will retrieve the x,y and z acceleration values from the ADXL345.
  //The results of the read operation will get stored to the values[] buffer.
  readRegister(DATAX0, 6, values);

  //The ADXL345 gives 10-bit acceleration values, but they are stored as bytes (8-bits). To get the full value, two bytes must be combined for each axis.
  //The X value is stored in values[0] and values[1].
  int x = ((int)values[1]<<8)|(int)values[0];
  //The Y value is stored in values[2] and values[3].
  int y = ((int)values[3]<<8)|(int)values[2];
  //The Z value is stored in values[4] and values[5].
  int z = ((int)values[5]<<8)|(int)values[4];
  
  //Print the results to the terminal.
  dataString += String(x);
  dataString += ",";
  Serial.print(x, DEC);
  Serial.print(',');
  dataString += String(x);
  dataString += ",";
  Serial.print(y, DEC);
  Serial.print(',');
  dataString += String(x);
  Serial.println(z, DEC);

  dataFile.println(dataString);

  // print to the serial port too:
  Serial.println(dataString);
  
  // The following line will 'save' the file to the SD card after every
  // line of data - this will use more power and slow down how much data
  // you can read but it's safer! 
  // If you want to speed up the system, remove the call to flush() and it
  // will save the file only every 512 bytes - every time a sector on the 
  // SD card is filled with data.
  dataFile.flush();
  
  // Take 1 measurement every 100 milliseconds
  delay(100);
}

//This function will write a value to a register on the ADXL345.
//Parameters:
//  char registerAddress - The register to write a value to
//  char value - The value to be written to the specified register.
void writeRegister(char registerAddress, char value){
  //Set Chip Select pin low to signal the beginning of an SPI packet.
  digitalWrite(chipSelectAC, LOW);
  //Transfer the register address over SPI.
  SPI.transfer(registerAddress);
  //Transfer the desired register value over SPI.
  SPI.transfer(value);
  //Set the Chip Select pin high to signal the end of an SPI packet.
  digitalWrite(chipSelectAC, HIGH);
}

//This function will read a certain number of registers starting from a specified address and store their values in a buffer.
//Parameters:
//  char registerAddress - The register addresse to start the read sequence from.
//  int numBytes - The number of registers that should be read.
//  char * values - A pointer to a buffer where the results of the operation should be stored.
void readRegister(char registerAddress, int numBytes, unsigned char * values){
  //Since we're performing a read operation, the most significant bit of the register address should be set.
  char address = 0x80 | registerAddress;
  //If we're doing a multi-byte read, bit 6 needs to be set as well.
  if(numBytes > 1)address = address | 0x40;
  
  //Set the Chip select pin low to start an SPI packet.
  digitalWrite(chipSelectAC, LOW);
  //Transfer the starting register address that needs to be read.
  SPI.transfer(address);
  //Continue to read registers until we've read the number specified, storing the results to the input buffer.
  for(int i=0; i<numBytes; i++){
    values[i] = SPI.transfer(0x00);
  }
  //Set the Chips Select pin high to end the SPI packet.
  digitalWrite(chipSelectAC, HIGH);
}

Thanks for the help!

I see you are using SPI.setDataMode() in setup(). If that is for the accelerometer you will need to reset the mode each time you go to access the accelerometer because the SD library is going to set the mode (and clock rate) suitable for the SD card each time it needs to access the card.

You are an amazing person!

Do you have the corrected version of the code ? I'm trying to build a similar device but I don't get where I should move the "SPI.setDataMode(SPI_MODE3);" out of the setup, in the loop ?