4x20lcd

Newzed

I am running a program in my Proto board for a 2x16 LCD.· I am using a· 4x20 LCD and the display works fine using the two top lines of the 4x20.· I have tried without success to modify the program so that I can use all four lines of my LCD.· I have attached the program, plus the object it uses.· Can someone please show me how to convert the 2x16 to a 4x20.· BTW, even though the program is for a 2x16, I am able to use 20 characters with the program as it stands.

Thanks

Sid

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mcstar

Were you ever able to figure out this issue? I've been working on the same problem for a couple days now. Sending the display to the correct address does not seem to help. Any ideas?

deSilva

You most likely have to adjust the addresses, they differ of course for 16 and 40 displays, as the latter have 2 controllers

        16x Module   20x4 Module
        also 40x
Line 1  00h - 0Fh    00h - 13h
Line 2  40h - 4Fh    40h - 53h
Line 3  10h - 1Fh    14h - 27h
Line 4  50h - 5fh    54h - 67h

Post Edited (deSilva) : 9/9/2007 9:50:15 PM GMT

deSilva

P.S.: This is from my driver, note lines and columns are zero-based here:

PUB GotoXY(Column, Row)| CRowOffset
  CRowOffset := lookupz(Row: $80, $C0, $94, $D4) 'for 4x20
  DataOut(column|CRowOffset)

boeboy

Check here http://obex.parallax.com/objects/104/·hope this helps.

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My computer, http://forums.parallax.com/showthread.php?p=630466

mcstar

Thanks! I was able to trace the issue down to insufficient power. The text was there, it was just so dim I coudn't see it. It was decieving however because whenever the display was in 1-Line mode, everything was bright as could be. When I went to 2-line mode, my batteries couldn't source enough current to maintain the voltage the display needed. I've learned that the four line display cannot be succesfully driven in 2-line mode from a 3.2volt source. Also, if your nicad batteries are only providing <4 volts, you can forget it also. I've also added POTs to both the contrast and LEDs, very important. So, mine was not a programming problem, but an electrical engineering one. Thanks for the input!