i use ds 1307 in my board and connect i2c bus to micro and use from atmel twi sample code.
but it not work.
please help me...

>>please help me..

What doesn't work, it doesn't ACK, the clock ticks backward?

Maybe you are using the wrong I2C slave address.
Maybe your hardware is wrong.
Maybe the oscillator isn't running.

If you actually want some help, provide the offending code and schematics, so people can provide specific suggestions rather than random guesses!!