I2C Read not giving correct values

[ptunn]

Hi Folks,

I’m trying to get my I2C interface working between an Uno board and my design.  I can write to the registers of the IC’s and everything works fine but I can’t read from them correctly.  Below is a screenshot of my VI, its reading back a byte of data but the data is not what I expect and doesn’t change when I change the register address…  Can anyone see where I’m going wrong?  Hope you can help!

Pat

[ChrissyC]

Hi Pat,

Are you sure you're writing the register address correctly? Instead of the array manipulation why not simply use the 'constant' option for the "I2C Data Bytes" terminal and write the address as 0x12 ?

-CC

[Kevin_F]

Hey ptunn,

Are you using Arduino 1.0 or one of the earlier versions? There were some changes in how this library is set up with Arduino 1.0.  I would suspect either an issue with addressing the register or the device.  What I2C device are you using?