Re: [avr-gcc-list] How to (efficeiently !!!) testabitwithinamulti-byte intege

[Dave Hansen]

From: Vincent Trouilliez <address@hidden>
> > FWIW, I always had good luck with the delay functions in delay.h for 
> short
> > hardcoded (usec) delays.
>
> Lucky you ! Other than wanting to avoid all this in-line stuff, the
> reason I replaced _delay_us(40) in my lcd routine, by an empty for loop,
> is that I accidentally realised that _delay_us(40) produced a 1,500us
> delay somehow !!! Couldn't figure out why, I set the F_CPU #define
> properly, and _delay_ms() works perfectly, but _delay_us clearly
> doesn't. Might be a bug with the particular delay of 40us, don't know,
> as don't use us delays anywhere else in my program.

Well, as I said earlier, I wrote my own delay_us routine from _delay_loop_2 
rather than using the supplied _delay_us.  I'm not sure why, it was so long 
ago.  Perhaps it didn't exist back then.

My longest delay (i.e. parameter supplied to the macro) was 10 usec, but I 
never measured to see how close it was.  It couldn't have been over about 
100 usec, or the system would not have performed..  I did measure a couple 
of 1 usec delays, and those were very close to exact.

Regards,
  -=Dave