TankMaster

Yes, two 10k resistors i parallel should correspond to a single 5k resistor. Well, it was just a thought.

 

Looking again at your code and comparing to the user manual you referred to, it seems you're are doing the reads wrong. You should read location 2 and 3 separately to get the high and low byte respectively. As it is now, you issue a series of four transactions where the read buffer gets overwritten by the the second read transaction. Your read buffer is 2 bytes but I think it only need be one byte since first you should read the high byte and then you read the low byte (the order does not seem to matter).

 

Also, I believe the location counter (address counter) auto-increments for each read performed so you could probably do something like this instead (here, the read buffer is still 2 bytes long):

xActions = new I2CDevice.I2CTransaction[]{	I2CDevice.CreateWriteTransaction(new byte[] { 0x02 }),	I2CDevice.CreateReadTransaction(RegisterValue),}int c = srf02.Execute(xActions, 1000);Debug.Assert(c > 0, "I2C write/read failed!");int val = (RegisterValue[0] << 8)|RegisterValue[1];

As you know, the Netduino is 5V tolerant and I wonder if the the LLC is really necessary - have you tried without it?

Hmm, seems like I have not understood this from the beginning... So LSB shall be skipped? Then why is both MSB and LSB available (Range High byte/MSB and Range Low byte/LSB)... I'm getting correct results now when only reading the MSB and doing the shift etc with it Why did you changed so that 2 is the number that means that the I2C operation has failed? I know that the N+ is 5V tolerant, but only the pins and the circuit board in my interpretation, I have never understood that the logic supports it as well...

Thanks for your time and help!

I agree, the byte order is equal to that of the Arduino code.

 

In my experience floating pins can sometimes result in strange phenomena and I try to avoid them even if it theoretically shouldn't matter. I normally use 100k pull-downs on unused pins though.

 

You could try using stronger I2C pull-ups, say 4k7 as see if that helps.

Okay, but how do I do that when I have the 10k's already on the LLC board? I tried to add resistors in parallel connected as pull-ups, together with the wire from/to the LLC on each voltage side, to achieve in theory an approx. 4.7k ohm resistor for SDA & SDL on both of the voltage sides. Is this not correct? I still get the wrong output data with this setup... Feels like I'm walking in the mist right now ^^

Perhaps you got the msb/lsb conversion wrong or the values are signed? The ratio between inches and centimetres seem correct most of the time. I trust the I2C pull-up resistors are in place. Got any pins floating?

I think the bitwise operations are right, not so much experience from it but the examples I have found used the one I have. The data result is 16 bit unsigned, so it must be that bitwise operation above that is right... The Arduino equivalent I found where this: http://arduino.cc/en...urceblock&num=1

reading = Wire.read();  // receive high byte (overwrites previous reading)reading = reading << 8;    // shift high byte to be high 8 bitsreading |= Wire.read(); // receive low byte as lower 8 bits

The LLC has 10k pull-ups, and as an extra precaution I have now as well connected the remaining pins on the LLC to ground, but that didn't give any difference (which it shouldn't do right? As the lines are separated, or?).