I2C problem (16F877A with DS1844)

[lissajous]

Is this the first time you've tried using this particular IC?
I've said it before, I'll say it again, start simple, work your way up...
How do you really know that the value is supposed to change? How do you really know that your interrupts are being handled the way you want them to be handled?

Replace the I2CWRITE commands with writes to the LCD, make sure you're logic is working, don't worry about what the chip does, just watch your numbers, see what they do first. Rewrite your program to write various values to the chip and the LCD and make sure the chip follows what you really want to do. Then integrate everything together. For all you know, there's something fundamentally wrong with the way you wrote the program.

Yes, it is the first time with this IC.

The hardware is ready , everything function functionate , excepting the I2C.
The LCD writes the right value, the interrupt also well functionate.

The trouble is that between the potentiometer outputs not mensurable the tuned worth. When there is off , here mensurable the 100k, run during wrongly the value.

excuse for my english
thanks