Em 12/4/2010 14:50, James Newton escreveu:
> http://techref.massmind.org/techref/io/lcd/44780.htm =

>
> Specifically, I'm wondering about the wait times between commands in the
> initialization function. What happens if you wait more than 15mS on the
> /second/ wait, or more than 4.1mS on the /third/ wait. E.g. you have alre=
ady
> waited 15mS and sent the command; now you are supposed to wait at least
> 4.1mS, but what if you wait 15mS? Does that re-start the sequence in the
> 44780 so that you are back at the /first/ step? =

>   =



You can wait *more* than the minimum. I used already 50ms for every wait
in the initialization sequence and everything was OK.

The reason for these long waits is because the busy flag cannot be
tested before the chip is initialized to a certain degree, so you need
to wait for the worst-case command execution time plus a safety margin.

I never tested specifically this, but it would be interesting to put
breakpoints on those waits and extend them to several seconds to see
what happens.


Best regards,

Isaac

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