I'm guessing the PB1 has been defined somewhere as a constant  -
probably 1 since it's PB1),

Then 1<<PB1 means "shift 1 left PB1 (i.e. 1) times. [ - The result is 2]

So the statement tests if the input of port B, pin 1 is high. (or
whichever pin PB1 actually points to).

RP


On 07/03/07, Mauricio Jancic <info@janso.com.ar> wrote:
> Hi,
>        I modifying a C code for an ATMEL chip, and I found this statement:
>
> if(!(PINB & (1<<PB1)))
>
>        Whats that? Specially the (1<<PB1) that I cant seem to figure out...
>
> Regards,
>
> Mauricio
>
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