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HD44780 parallel problem

KAiNAM

New member
Hi there,
thanks for reading this, when i give the lcd power i get two full black lines, on lines 1 and 3.

after ive started crystal control they disapear and i can get stuff too appear on the lcd. the problem is the first 8 columns are readable and the rest are not, they are significantly lighter, not readable even at full contrast while the first 8 are perfectly visible.


Any thoughts, thanks jake
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KAiNAM

New member
iv ran the CFAH WinTest software, it does its little dance and fills up the entire lcd with chars, and they all work.
the first 8 columns are still at the correct contrast and the rest are still barely visible.

but when the lcd starts up and bring up the two complete black bars on lines 1 and 3 they are contrasted correctly.

which confuses me, if the lcd can create blocks in those other columns at the correct contrast why are these chars not working?


???? - confused
 

KAiNAM

New member
Seeing as the lcd is working properly apart from the contrast weirdness, it wont be a wirring problem correct? or a bad solder joint?
 

KAiNAM

New member
"Start with pin 3 (Vo) at about 1 volt." ???

i just tried the lcd with a winamp plugin, same problem still.
(was hoping it was software)
 
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