LCD going crazy!!!

This is a test program for my LCD. Sometime I can read on the screen but the following second the words are jumping from one line to another and the letters and just going about anywhere... any thoughts

Code:

---

'LCD testing program

INCLUDE "modedefs.bas"
OSCCON = %01110000 '8 Mhz

CMCON = 7 : ANSEL = 0 : ADCON1 = 7
'/////////////////////////
'// LCD configuration //
'/////////////////////////

DEFINE LCD_DREG PORTB ' Set LCD Data port
DEFINE LCD_DBIT 4 ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTA ' Set LCD Register Select port
DEFINE LCD_RSBIT 2 ' Set LCD Register Select bit
DEFINE LCD_EREG PORTA ' Set LCD Enable port
DEFINE LCD_EBIT 3 ' Set LCD Enable bit
DEFINE LCD_BITS 4 ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2 ' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 250
DEFINE CHAR_PACING 2000
pause 1000


Mainloop:

        lcdout $FE,1, " This is a test"                    '
        lcdout $FE,$C0, "Next or Select"                '
        pause 200
           
GOTO Mainloop
End

---

Just thinking aloud. Have you tried telling PBP
define OSC 8
so that it knows you are working at 8MHz and can adjust its timings accordingly.

try a pause between each lcd out
Some of the cheaper LCD's are not good with fast transfers
You can also try adjusting the LCD commandUs etc

I did try using define, same thing happens. I have been using this LCD for a couple of years now. This is happening since I upgraded to windows7 64 bit. and using microcode studio

K

I also changed pic, used different pins for RS RE LCDout. I just have not changed the LCD module with a new one.. maybe its the LCD ...

How about:

Code:

---


Mainloop:

        LCDOUT $FE,1    ' Clear display
        PAUSE 50
        LCDOUT $FE,2," This is a test"      ' Move to 1st line, writes 15 CHAR
        LCDOUT $FE,$C0,"Next or Select"    ' Move to 2nd line, writes 14 CHAR
        PAUSE 200
           
GOTO Mainloop
End

---

taking a cue from Louie, I'd say, you're writing too fast for the lcd to keep pace.

You can try this

Code:

---


Mainloop:         
                LCDOUT $FE,1    ' Clear display       
                LCDOUT $FE,2," This is a test"      ' Move to 1st line, writes 15 CHAR       
                LCDOUT $FE,$C0,"Next or Select"    ' Move to 2nd line, writes 14 CHAR
STOP
End

---

I think the revolution of the earth might of affected my chip. no but seriously I did not touch anything and it is working now...
even with pause 100 after the LCDout...
Althought i do not understand why I need these two line for my frequency:
OSCCON = %01110000 '8 Mhz
Define OSC 8


the OSCCON = %01110000 says that is is running at 8Mhz...

The program is not stable if I do not have BOTH of these lines... why ??


ken

Quote:

---

OSCCON = %01110000 '8 Mhz
Define OSC 8

---

OSSCON=%0111000 ... configures the actual PIC hardware

Define OSC 8 ... is a directive to the COMPILER to notifiy it that you have set the PIC hardware for 8 MHz

Got my hopes up too quickly ... :(
I wrote this clock program.. works good, but sooner or later, after 1 minutes or 4 minutes the Display acts up go crazy, sometimes it comes back showing a proper time.. but its really not stable...

K

Quote:

---

'LCD testing program

INCLUDE "modedefs.bas"
OSCCON = %01110000 '8 Mhz
Define OSC 8

CMCON = 7 : ANSEL = 0 : ADCON1 = 7
'/////////////////////////
'// LCD configuration //
'/////////////////////////

DEFINE LCD_DREG PORTA ' Set LCD Data port
DEFINE LCD_DBIT 0 ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTB ' Set LCD Register Select port
DEFINE LCD_RSBIT 7 ' Set LCD Register Select bit
DEFINE LCD_EREG PORTB ' Set LCD Enable port
DEFINE LCD_EBIT 6 ' Set LCD Enable bit
DEFINE LCD_BITS 4 ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2 ' Set number of lines on LCD
DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 250
DEFINE CHAR_PACING 2000
pause 500



'/////////////////////////
'// PIN configuration //
'/////////////////////////

TRISB = %00000000 ' Set PORTB to all output
TRISA = %11111111 ' Set PORTA to all input



'///////////////////////////////////////////////
'// Variable Declaration and initialization //
'///////////////////////////////////////////////

SDApin var PORTB.1 ' RTC data
SCLpin var PORTB.4 ' RTC clock


Total_time var byte
RTCSec var byte :RTCMin var byte :RTCHour var byte :RTCWDay var byte :RTCDay var byte :RTCMonth var byte :RTCYear var byte :RTCCtrl var byte



lcdout $FE,1, "Bienvenue"
lcdout $FE,$C0, "Welcome"
pause 500


'////////////////////////////////////////////////////
'////////////////// PROGRAM /////////////////////////
'////////////////////////////////////////////////////
I2CWRITE SDApin,SCLpin,$D0,$00,[$49,$59,$00,$00,$00,$00,$00,$00] ' Write to DS1307 to start counter at ZERO
Pause 30

Mainloop:


I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour,RTCWDay,RTCDay,RTCMonth,RTCY ear,RTCCtrl]
Pause 30
'Will get the time from timer chip and do a 60 min count down
'Also add interrupt if someone presses start to view the charge/discharge cycle
LCDOUT $FE,1 ' Clear display
PAUSE 20
lcdout $FE,2, "Kens Clock"
lcdout $FE,$C0, "time: ", HEX2 RTCHour, ":", HEX2 RTCMin, ":", HEX2 RTCSec
Pause 300
Goto Mainloop
end

---

Question time:
1 - How is your circuit built? Breadboard? or a proper PCB?
2 - How about decoupling capacitors. Do you have them 0.1uF across the supply rails?
3 - How are you powering the circuit? Chances are you have a bad ac adapter (assumption)

I know I'm asking the obvious, but, in times of stress, you need to recheck these.

regards
Jerson

I am using a breadboard, powered from a 12v battery and a 10uf 16v rail to rail cap. I might redo the circuit on another breadboard using different wires and parts tonight..

k

Changed the breadboard and all parts. Works perfectly now. I think the breadboard might be damaged...
ken