Thanks for your help with my I2C problem. I have now found the AN554 application note, and it gives me another question. When you download the source code and extract the ZIP file you will get about 20 files. How do I use them correct ?? There Is a file called I2C.asm which I think is the main program. But as far as I can se are none of the files including macro's (I2C_low.ins and I2C_high.inc), included in the I2C.asm file. And what about the header file I2C.h. Please help me in useing all these files in the correct way !! With kind regards GDK-SSJ - Steen Schelle Jensen Dept.: 1545 Internet e-mail: ssjensen@grundfos.com