Hello,
I’m trying to get the ADXL 345 up and running with the Spark Core, using the ADXL 345 library. I have tried both including the library into a project, and using the ‘no library’ variant, which talks directly to registers on the break out board.
Unfortunately, I’m not having much success at reading the X, Y and Z values at the moment (or any of the more advanced ‘tap’ features of the board.
Here is the code I’m using:
// Cabling for i2c using Sparkfun breakout with a Spar Core
// Spark Core <-> Breakout board
// Gnd - GND
// 3.3v - VCC
// 3.3v - CS
// Digital 0 - SDA
// Digital 1 - SCL
#define DEVICE (0x53) // Device address as specified in data sheet
byte _buff[6];
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
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
Serial.begin(57000); // start serial for output. Make sure you set your Serial Monitor to the same!
Serial.print("init");
//Put the ADXL345 into +/- 4G range by writing the value 0x01 to the DATA_FORMAT register.
writeTo(DATA_FORMAT, 0x01);
//Put the ADXL345 into Measurement Mode by writing 0x08 to the POWER_CTL register.
writeTo(POWER_CTL, 0x08);
}
void loop()
{
readAccel(); // read the x/y/z tilt
delay(500); // only read every 0,5 seconds
}
void readAccel() {
uint8_t howManyBytesToRead = 6;
readFrom( DATAX0, howManyBytesToRead, _buff); //read the acceleration data from the ADXL345
// each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!
// thus we are converting both bytes in to one int
int x = (((int)_buff[1]) << 8) | _buff[0];
int y = (((int)_buff[3]) << 8) | _buff[2];
int z = (((int)_buff[5]) << 8) | _buff[4];
Serial.print("x: ");
Serial.print( x );
Serial.print(" y: ");
Serial.print( y );
Serial.print(" z: ");
Serial.println( z );
}
void writeTo(byte address, byte val) {
Wire.beginTransmission(DEVICE); // start transmission to device
Wire.write(address); // send register address
Wire.write(val); // send value to write
Wire.endTransmission(); // end transmission
}
// Reads num bytes starting from address register on device in to _buff array
void readFrom(byte address, int num, byte _buff[]) {
Wire.beginTransmission(DEVICE); // start transmission to device
Wire.write(address); // sends address to read from
Wire.endTransmission(); // end transmission
Wire.beginTransmission(DEVICE); // start transmission to device
Wire.requestFrom(DEVICE, num); // request 6 bytes from device
int i = 0;
while(Wire.available()) // device may send less than requested (abnormal)
{
_buff[i] = Wire.read(); // receive a byte
i++;
}
Wire.endTransmission(); // end transmission
}
Here is my breadboard:
I confess to being a bit of a newbie here, and I may have bitten off more than I can chew, but would welcome any advice or guidance. Thanks!
~ M