>>Mine didn't work the first time either. For me, the problem was no more
than
>>just playing with the contrast though.( I felt REAL smart after that one)

>What does yours do when initialized and before it is initialized?


On power up, my display shows the background slightly darkened on the top line
only.

>the first line goes all black

I believe your contrast needs to be adjusted slightly to make this black the
slightly visible backgound, not easily visible foreground.  If I set my
contrast to 0 volts, I see a black bar as you describe only on line 1.  (my
normal contrast is 0.75 Volts for a 5.2V supply)

Stepping through the initialization code, my display remains the same 1 line
black background until I tell it to use a 2 line display in the function set
(4th code).  At this point the display background gets lighter.  (same voltage
for 2 lines = 1/2 darkenss?)
After the last code, display on, the cursor appears top left (if you turned
the cursor on in the display on code.)

I have used an Optrex 24x2 LCD display
I too had contrast problems..  I saw 4.5-5 volts, but I did not read the label
for the contrast as stated in the spcec (VCC-VEE).  I tried many things,
including a second display until I ran the contrast from end to end and saw
the background appear near zero volts.

I am using the 8 bit interface, so my code will not directly convert.
I think I also had some signals mixed up in my programming.  (I do not
remember the details.)
My initialization data matches Optrex recomendation for the 8 bit interface.

 retlw B'00110000' ;initilize display
 retlw B'00110000' ;initilize display
 retlw B'00110000' ;initilize display
 retlw B'00111000' ;8 bit data transfer, 2 lines
 retlw B'00001000' ;Display off
 retlw B'00000001' ;Clear Display
 retlw B'00000110' ;Display Mode Shift Cursor
 retlw B'00001111' ;Display on - Cursor ON Blink ON

Good Luck,
Jeff Berosik

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