piclist 2002\08\17\101222a >
Thread: LCD Contrast Variation
face picon face BY : Jinx email (remove spam text)

> Are rs, rw & en on the same port? Personally I like a nop between
> them if so to avoid the famous RMW bug. (feature?)

I haven't noticed a problem with adjacent bits in the same port (for
LCDs anyway) and I don't put nops between them. However I do tend
to put nops between instructions to the same bit if, as I understand
or recall it, the external circuit is slowish to respond and there might
be a rise-time delay that could mess up the r-m-w of the next instruction

Sometimes it's there just for a bit of timing

> >          bsf    en            ;write 0x30 again
> >          nop
> >          bcf    en

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<001301c245f5$354ae500$9e4b61cb@joe> 7bit

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