AVR-Chat

See below:

kernels_nz wrote:
> Hi Alex,
> 
> Thanks for the quick response, I understand what the code does, just
> not why a bitwise AND is performed and what (1<<UDRE) "means". In my

   It means shift the '1' to the left UDRE places.  It is common short 
hand in C.

> baby-C, I would probably have written 
> 
> while (UCSRA.x != 0); 

   Which is perfectly fine if UCSRA is defined to work that way.  I 
often define structs for SFRs so that I'd do something like:

while (UCSRAbits.UDRE != 0)

> where x is the UDRE bit. Any advantages to the way it's done below ?

Do it each way and see which one compiles to a smaller assembly block, 
and use that one. :)

DLC

> cheers
> Hein B
> 
> 
> --- In AVR-Chat@yahoogroups.com, "Alex Shepherd" <lists06@...> wrote:
> 
>>>while ((UCSRA & (1<<UDRE))==0);
>>
>>Loop around checking the state of the UDRE bit in the UCSRA port
> 
> until the
> 
>>bit value is NOT 0
>>
> 
> 
> 
> 
> 
> 
>  
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-- 
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Dennis Clark    TTT Enterprises
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