Merge pull request #9 from hmtroeger/master

Added FIFO functionallity for Burst Read 
Thanks for your PR.

ADXL345.cpp

@@ -84,6 +84,8 @@ void ADXL345::readFrom(byte address, int num, byte _buff[]) {
     Wire.beginTransmission(ADXL345_DEVICE); // start transmission to device 
     Wire.write(address);             // sends address to read from
     Wire.endTransmission();         // end transmission
+    
+    Wire.beginTransmission(ADXL345_DEVICE); // start transmission to device
     Wire.requestFrom(ADXL345_DEVICE, num);    // request 6 bytes from device
     
     int i = 0;
@@ -96,6 +98,7 @@ void ADXL345::readFrom(byte address, int num, byte _buff[]) {
         status = ADXL345_ERROR;
         error_code = ADXL345_READ_ERROR;
     }
+    Wire.endTransmission();         // end transmission
 }
 
 // Gets the range setting and return it into rangeSetting
@@ -500,7 +503,8 @@ void ADXL345::setLowPower(bool state) {
 double ADXL345::getRate(){
     byte _b;
     readFrom(ADXL345_BW_RATE, 1, &_b);
-    _b &= B00001111;
+
+	_b &= B00001111;
     return (pow(2,((int) _b)-6)) * 6.25;
 }
 
@@ -601,6 +605,8 @@ void ADXL345::setRegisterBit(byte regAdress, int bitPos, bool state) {
     writeTo(regAdress, _b);  
 }
 
+
+
 bool ADXL345::getRegisterBit(byte regAdress, int bitPos) {
     byte _b;
     readFrom(regAdress, 1, &_b);
@@ -626,6 +632,63 @@ void ADXL345::printAllRegister() {
     }
 }
 
+// set the operation mode
+
+void ADXL345::setMode(byte operationMode){
+	byte _b;
+    readFrom(ADXL345_FIFO_CTL, 1, &_b);
+	_b &=~(0b11000000);  //clearing bit 6 and 7 
+	_b |=(operationMode <<6); //setting op mode
+	
+	
+	//setRegisterBit(ADXL345_FIFO_CTL, 6, operationMode);
+	writeTo(ADXL345_FIFO_CTL, _b); 
+}
+// readback mode
+
+byte ADXL345::getMode(void){
+	byte _b;
+    readFrom(ADXL345_FIFO_CTL, 1, &_b);
+	_b &= 0b11000000;  //masking bit 6 and 7 
+	_b =(_b>>6); //setting op mode
+	return _b;
+}
+
+// set watermark
+
+void ADXL345::setWatermark(byte watermark){
+	byte _b, _w;
+	
+    readFrom(ADXL345_FIFO_CTL, 1, &_b);
+	_b &=(0b11100000);  //clearing bit 0 to 4
+	_w = watermark & (0b00011111);  //clearing highest 3 bits in waterlevel
+	_b |=_w; //setting waterlevel in operationmode register
+	//setRegisterBit(ADXL345_FIFO_CTL, 6, operationMode);
+	writeTo(ADXL345_FIFO_CTL, _b); 
+}
+
+// read how many samples in Fifi
+
+byte ADXL345::getFifoEntries(void){
+	byte _b;
+	readFrom(ADXL345_FIFO_STATUS, 1, &_b);
+	_b &=  0b00111111;
+
+	return _b;
+}
+
+void ADXL345::burstReadXYZ(int *x, int *y, int *z, byte samples) {
+	for (int i=0; i<samples; i++){
+		readFrom(ADXL345_DATAX0, ADXL345_TO_READ, _buff); //read the acceleration data from the ADXL345
+		x[i] = (short)((((unsigned short)_buff[1]) << 8) | _buff[0]);   
+		y[i] = (short)((((unsigned short)_buff[3]) << 8) | _buff[2]);
+		z[i] = (short)((((unsigned short)_buff[5]) << 8) | _buff[4]);
+	}
+}
+
+	
+	
+
 void print_byte(byte val){
     int i;
     Serial.print("B");

ADXL345.h

@@ -112,6 +112,12 @@
 #define ADXL345_READ_ERROR 1 // problem reading accel
 #define ADXL345_BAD_ARG    2 // bad method argument
 
+#define ADXL345_MODE_BYPASS 0x00 	//0000
+#define ADXL345_MODE_FIFO 0x01 		//0001
+#define ADXL345_MODE_STREM 0x02 	//0010
+#define ADXL345_MODE_TRIGGER 0x03 	//0011
+
+
 class ADXL345
 {
 public:
@@ -201,6 +207,13 @@ public:
     void setInterruptMapping(byte interruptBit, bool interruptPin);
     bool isInterruptEnabled(byte interruptBit);
     void setInterrupt(byte interruptBit, bool state);
+	
+	
+	void setMode(byte modeBit); // setting operation mode
+	byte getMode(); 
+	void setWatermark(byte watermark);
+	byte getFifoEntries(void);		// reading number of samples from fifo
+	void burstReadXYZ(int *x, int *y, int *z, byte samples);  // burst read function for getting all samples from fifo 
     
     void getRangeSetting(byte* rangeSetting);
     void setRangeSetting(int val);
@@ -215,7 +228,7 @@ public:
     bool getJustifyBit();
     void setJustifyBit(bool justifyBit);
     void printAllRegister();
-    
+
 private:
     void writeTo(byte address, byte val);
     void readFrom(byte address, int num, byte buff[]);

examples/ADXL345_FIFO_demo_code/ADXL345_FIFO_demo_code.ino

@@ -0,0 +1,160 @@
+/*****************************************************************************/
+//  Function:    Uses ADXL345 in FIFO mode. Up to 33 samples of X/Y/Z 
+//               acceleration are stored in the FIFO of the sensor and are than
+//               read back within a bulk read. FIO mode is essential for low 
+//               power applications where only the sensor stays awake.
+//  Hardware:    3-Axis Digital Accelerometer(+-16g)
+//  Arduino IDE: Arduino-1.8.9
+//  Author:  Hans "Blackcow"     
+//  Date:    SEP 13,2019
+//  Version: v1.0
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+//  You should have received a copy of the GNU Lesser General Public
+//  License along with this library; if not, write to the Free Software
+//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+//
+/*******************************************************************************/
+
+/*****************************************************************************/
+//  Function:    Get the accelemeter of X/Y/Z axis and print out on the 
+//          serial monitor.
+//  Hardware:    3-Axis Digital Accelerometer(��16g)
+//  Arduino IDE: Arduino-1.0
+//  Author:  Frankie.Chu    
+//  Date:    Jan 11,2013
+//  Version: v1.0
+//  by www.seeedstudio.com
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+//  You should have received a copy of the GNU Lesser General Public
+//  License along with this library; if not, write to the Free Software
+//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+//
+/*******************************************************************************/
+
+#include <Wire.h>
+#include <ADXL345.h>
+
+
+ADXL345 adxl; //variable adxl is an instance of the ADXL345 library
+
+void setup(){
+  Serial.begin(115200);
+  adxl.powerOn();
+
+  //set activity/ inactivity thresholds (0-255)
+  adxl.setActivityThreshold(75); //62.5mg per increment
+  adxl.setInactivityThreshold(75); //62.5mg per increment
+  adxl.setTimeInactivity(10); // how many seconds of no activity is inactive?
+ 
+  //look of activity movement on this axes - 1 == on; 0 == off 
+  adxl.setActivityX(1);
+  adxl.setActivityY(1);
+  adxl.setActivityZ(1);
+ 
+  //look of inactivity movement on this axes - 1 == on; 0 == off
+  adxl.setInactivityX(1);
+  adxl.setInactivityY(1);
+  adxl.setInactivityZ(1);
+ 
+  //look of tap movement on this axes - 1 == on; 0 == off
+  adxl.setTapDetectionOnX(0);
+  adxl.setTapDetectionOnY(0);
+  adxl.setTapDetectionOnZ(1);
+ 
+  //set values for what is a tap, and what is a double tap (0-255)
+  adxl.setTapThreshold(50); //62.5mg per increment
+  adxl.setTapDuration(15); //625us per increment
+  adxl.setDoubleTapLatency(80); //1.25ms per increment
+  adxl.setDoubleTapWindow(200); //1.25ms per increment
+ 
+  //set values for what is considered freefall (0-255)
+  adxl.setFreeFallThreshold(7); //(5 - 9) recommended - 62.5mg per increment
+  adxl.setFreeFallDuration(45); //(20 - 70) recommended - 5ms per increment
+ 
+  //setting all interrupts to take place on int pin 1
+  //I had issues with int pin 2, was unable to reset it
+  adxl.setInterruptMapping( ADXL345_INT_DATA_READY_BIT,   ADXL345_INT1_PIN );
+  adxl.setInterruptMapping( ADXL345_INT_SINGLE_TAP_BIT,   ADXL345_INT1_PIN );
+  adxl.setInterruptMapping( ADXL345_INT_DOUBLE_TAP_BIT,   ADXL345_INT1_PIN );
+  adxl.setInterruptMapping( ADXL345_INT_FREE_FALL_BIT,    ADXL345_INT1_PIN );
+  adxl.setInterruptMapping( ADXL345_INT_ACTIVITY_BIT,     ADXL345_INT1_PIN );
+  adxl.setInterruptMapping( ADXL345_INT_INACTIVITY_BIT,   ADXL345_INT1_PIN );
+  adxl.setInterruptMapping(ADXL345_INT_WATERMARK_BIT,     ADXL345_INT1_PIN);
+ 
+  //register interrupt actions - 1 == on; 0 == off  
+  adxl.setInterrupt( ADXL345_INT_DATA_READY_BIT, 1 );
+  adxl.setInterrupt( ADXL345_INT_SINGLE_TAP_BIT, 0);
+  adxl.setInterrupt( ADXL345_INT_DOUBLE_TAP_BIT, 0);
+  adxl.setInterrupt( ADXL345_INT_FREE_FALL_BIT,  0);
+  adxl.setInterrupt( ADXL345_INT_ACTIVITY_BIT,   0);
+  adxl.setInterrupt( ADXL345_INT_INACTIVITY_BIT, 0);
+  adxl.setInterrupt( ADXL345_INT_WATERMARK_BIT, 1);
+
+  //setting lowest sampling rate
+  adxl.setRate(6.25);
+  //setting device into FIFO mode
+  adxl.setMode(ADXL345_MODE_FIFO);
+  //set watermark for Watermark interrupt 
+  Serial.println("Current operation mode: ");
+  Serial.println(adxl.getMode());
+  adxl.setWatermark(30); 
+  delay(100);
+}
+
+void loop(){
+  //Boring accelerometer stuff   
+  int x[32],y[32],z[32];
+  byte fifoentries,intEvent;
+
+
+  fifoentries = adxl.getFifoEntries();
+  if ((fifoentries%5)==0)             //Printing only every 5th sample to prevent spam on console
+  {
+    Serial.print("Current FIFO entries: ");
+    Serial.println(fifoentries);
+  }
+
+  
+  intEvent = adxl.getInterruptSource();  // reading interrupt status flags
+  if (adxl.triggered(intEvent,ADXL345_WATERMARK) )   // if watermark interrupt occured
+  {
+      Serial.println("Watermark interrupt triggered. Fetching data now." );
+  
+  if (fifoentries != 0){
+    adxl.burstReadXYZ(&x[0],&y[0],&z[0],fifoentries);   // reading all samples of FIFO
+    for (int i=0;i<fifoentries;i=i+5)       //Printing only every 5th sample to prevent spam on console
+    {
+      Serial.print("FIFO data sample: ");
+      Serial.print(i);      
+      Serial.print(", x: ");
+      Serial.print(x[i]);
+      Serial.print(", y: ");
+      Serial.print(y[i]);
+      Serial.print(", z: ");
+      Serial.println(z[i]);
+    }
+    
+    }
+  }
+  delay(200);
+}