Trouble with the AXDL345_I2C accelerometer.

[LukeS]

I apologize in advance for creating another accelerometer thread, but none of the others were able to help me, and I didn't want to hijack l0stboy's, in case we're having different problems.

My problem is the one most people are having: I always read 0.0 on all axis.

I have the module connected to the I2C port on the sidecar, yes I2C closest to the NXT connector, not the digital outs next to it.

We are using the new flat ribbon cable to talk to the DSC. One of the connectors was flipped, but we fixed it, per the instructions on the KoP site. It has been verified working by using two PWM servos, and two digital encoders.

I have verified that the pins are connected one-to-one from the accelerometer to the sidecar. I have tested the cable using an ohm-meter, and have while it is connected measured 5.1V on the "5V" pin, and 4.7V on the "SDA" and "SCL". I do not have easy access to an oscilloscope, but can get one if truly necessary.

Looking at the spec sheet for the ADXL345, and the WPILibJ source code, we noticed that the read bit is not set during I2C.read(), so I tried replacing

registerAddressArray[0] = (byte) registerAddress;

with

registerAddressArray[0] = (byte) (registerAddress | 0x01);

To clarify, why I did this is because the spec sheet (from Analog Devices) says

the 7-bit I2C address for the device is 0x1D, followed by the R/W bit. This translates to 0x3A for a write and 0x3B for a read.

However, this did not fix the problem either.

We have also tried replacing the accelerometer, but it didn't work either.

Here is the code I am running to test the accelerometer:

package edu.wpi.first.wpilibj.templates;

import edu.wpi.first.wpilibj.ADXL345_I2C;
import edu.wpi.first.wpilibj.IterativeRobot;

public class RobotTemplate extends IterativeRobot {

	ADXL345_I2C accel;

	public void robotInit() {
		accel = new ADXL345_I2C(1, ADXL345_I2C.DataFormat_Range.k2G);
	}

	public void teleopPeriodic() {
		ADXL345_I2C.AllAxes vals = accel.getAccelerations();
		System.out.println(
				" X: " + vals.XAxis+
				" Y: " + vals.YAxis+
				" Z: " + vals.ZAxis);
	}
}

Any help is greatly appreciated.