Posted on November 16, 2014 at 23:55I am unable to detect an interial interrupt from the LIS3DH accelerometer as a result of moving the sensor on a flat surface. The sensor is interfaced with an Arduino Uno using I2C. I am using the example in section 6.3.1 of AN3308, LIS3DH application notes. I can successfully read acceleration values. I also tried checking both interrupt ports, int 1 and int 2.
Please see attached Arduino code below.
&sharpinclude <Wire.h>
const int LIS3DH_ADDR = 0x18;
int pin = 13;
int int1Pin = 2;
int int2Pin = 3;
/* I2C Communication Set-up ---------------------------------------------------------*/
unsigned int readRegister(byte reg) {
Wire.beginTransmission(LIS3DH_ADDR);
Wire.write(reg);
Wire.endTransmission();
Wire.requestFrom(LIS3DH_ADDR, 1);
return Wire.read();
}
void writeRegister(byte reg, byte data) {
Wire.beginTransmission(LIS3DH_ADDR);
Wire.write(reg);
Wire.write(data);
Wire.endTransmission();
}
/* Initialize accelerometer in the host processor. ----------------------------------*/
//It only needs to be executed one time after power up in initialization routine.
void init_ACC(void)
{
// configurations for control registers
writeRegister(0x20, 0xA7); //Write A7h into CTRL_REG1; // Turn on the sensor with ODR = 100Hz normal mode.
writeRegister(0x21, 0x00); //Write 00h into CTRL_REG2; // High-pass filter (HPF) disabled
writeRegister(0x22, 0x40); //Write 40h into CTRL_REG3; // ACC AOI1 interrupt signal is routed to INT1 pin.
writeRegister(0x23, 0x00); //Write 00h into CTRL_REG4; // Full Scale = +/-2 g
writeRegister(0x24, 0x00); //Write 00h into CTRL_REG5; // Default value. Interrupt signals on INT1 pin is not latched.
//Users don�t need to read the INT1_SRC register to clear the interrupt signal.
// configurations for wakeup and motionless detection
writeRegister(0x32, 0x10); //Write 10h into INT1_THS; // Threshold (THS) = 16LSBs * 15.625mg/LSB = 250mg.
writeRegister(0x33, 0x00); //Write 33h into INT1_DURATION; // Duration = 1LSBs * (1/10Hz) = 0.1s.
writeRegister(0x30, 0x0A); //Write 0Ah into INT1_CFG; // Enable XLIE, YLIE interrupt generation, OR logic.
}
void setup() {
Wire.begin();
Serial.begin(9600);
int res = readRegister(0x0F); //WHO_AM_I
Serial.println(res);
pinMode(pin, OUTPUT); // sets the digital pin 13 as output
pinMode(int1Pin, INPUT); // sets the digital pin 2 as input
pinMode(int2Pin, INPUT); // sets the digital pin 2 as input
}
void loop() {
//Read both interrupt pins
int int1 = digitalRead(int1Pin);
int int2 = digitalRead(int2Pin);
Serial.print(int1);
Serial.print('','');
Serial.println(int2);
if (digitalRead(int1Pin) == 0 && digitalRead(int2Pin) == 0){
//if both are low write
writeRegister(0x30, 0x0A);
}
else {
digitalWrite(pin, HIGH);
int intEvent = readRegister(0x31);
Serial.println(intEvent);
delay(2000);
}
delay(0);
}
#lis3dh-interrupt #accelerometer #lis3dh #lis3dh-interrupt
