Need Help LCD 20x4 Initial problem

Duke · 2006-06-13 03:31

Hello,

I have a problem about standard character LCD 20x4 it is not stable (sometimes cannot display).
I think it is because of my programing, In the LCD initial stage·I use the program from my old 16x2 program
because·I don't how to initial 20x4 LCD, Anyway·it works·the LCD can display but·after·on-off many times it doesn't work

The·program is like this.

·'*** Note LCD Module use data 7 bit = D7 D6 D5 D4 RS R/W EN ***
PAUSE 600······· 'LCD wait power on >500 ms
LCDCMD 1,48······ 'Send wakeup seq to LCD
PAUSE 10········· 'Meet LCD spec
LCDCMD 1,48······ 'Send wakeup seq to LCD
PAUSE 1·········· 'Meet LCD spec
LCDCMD 1,48······ 'Send wakeup seq to LCD
PAUSE 1·········· 'Meet LCD spec
LCDCMD 1,32······ 'Set data 4 bit
LCDCMD 1,40······ 'Set to 2 line mode 5x8 font
LCDCMD 1,8······· 'Turn display off
LCDCMD 1,12······ 'Turn display on without cursor
LCDCMD 1,6······· 'Set to auto-increment cursor (no display shift)
LCDCMD 1,1······· 'Clear the display

'**** End Initial LCD *************************

I think the fault is from my programing. I anyone know how to initial the LCD please help me
correct this program.

Thank you.

Duke..

Chris Savage · 2006-06-13 03:38

Duke,
·· Try the following code and see if it helps.· Let me know how you make out.· Bear in mind, Lcd will need to be set to 1 (constant).· You will also need a variable (nib will suffice) named temp to use this code as it is.

Init_Lcd:
  PAUSE 1000
  FOR temp = 0 TO 2
    LCDCMD Lcd, 48                      ' Reset LCD (Send 3 times)
    PAUSE 5                             ' Delay Require By LCD Specs
  NEXT
  LCDCMD Lcd, 32                        ' Set 4-bit Mode
  LCDCMD Lcd, 40                        ' Set 2-line Mode
  LCDCMD Lcd, 12                        ' Turn On Display With No Cursor
  LCDCMD Lcd, 6                         ' Set To Auto-Increment Cursor
  LCDCMD Lcd, 1                         ' Clear Display
' -----[noparse][[/noparse] Main Routine ]----------------------------------------------------
Main:
  LCDOUT Lcd, 1, [noparse][[/noparse]"Hello, this is"]   ' Clear LCD & Print Line 1 Text

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Need Help LCD 20x4 Initial problem

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