At 15:48 09.02.2006 +0100, you wrote: >Is it wrong to expect "TWCR = 128" after the command "outb(TWCR, >_BV(TWINT));"? >Why is the TWINT-bit not set? Have a look to the ATmega128 datasheet. TWINT=1 _clears_ the corresponding register bit. Harald