LCD and PIC18F2685 - Weird LCD behavior

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I'm using the 28 pin demo board from Microchip (see schematic below) with a 18F2685pic, MPLAB IDE and Picbasic pro v2.47, and ICD2 for programming. The LCD pins are connected in the default manner. I'm using the internal oscilator @8 MHZ and the config file in my pbp directory is modified accordingly, that is:

Code:

__CONFIG _CONFIG1H, _OSC_IRCIO67_1H

The behavior the LCD is experiencing is bizzare: First, it shows black boxes on the first line (so everything fine until now). When releasing from reset, still black boxes on the first line. If I take LCD's Vdd out for a second I start seeing weird characters. Plug it back in, weird characters again. When I try to output "123456789" I get "1230123"(that is, with the vdd plugged in). If I try to output "hello", werid characters again.

Some of the pins on the demo board are occupied with the default components(leds, pot) but I tried to stay away these pins. Just RB3 (LCD E(nable) is on the same pin as one of the board's LED)

and the code:

Code:

' display a message on the lcd DEFINE OSC 8 DEFINE LCD_DREG PORTB ' portb is the port used for data lines DEFINE LCD_DBIT 4 'the pin on port connected to LCD pin DB4 DEFINE LCD_RSREG PORTA 'pic port used for the RS line DEFINE LCD_RSBIT 4 ' port pin where RS pin is connected DEFINE LCD_EREG PORTB ' PIC port where E pin is connected DEFINE LCD_EBIT 3 ' port pin where E pin is connected DEFINE LCD_BITS 4 ' 4 bit mode DEFINE LCD_LINES 2 ' 2 LCD lines DEFINE LCD_COMMANDUS 2000 'delay between LCD commands DEFINE LCD_DATAUS 50 'delay between data sent adcon1=7 trisb=0 ' port b all outputs trisa=0 ' port a all outputs intcon2.7=0 'enable pull ups OSCCON = %01110000 '---main program repeta: high portb.0 ' light led to see when main loop is running LCDOUT $fe,1 ' Clears LCD LCDOUT $fe,2, "hello" ' Returns to beginning of line 1 and writes "string" pause 1000 goto repeta

The lcd is a optorex dmc16207 which is Hitachi HD44780 compatible

Try this:

Code:

DEFINE OSC 8 DEFINE LCD_DREG PORTB ' portb is the port used for data lines DEFINE LCD_DBIT 4 'the pin on port connected to LCD pin DB4 DEFINE LCD_RSREG PORTA 'pic port used for the RS line DEFINE LCD_RSBIT 4 ' port pin where RS pin is connected DEFINE LCD_EREG PORTB ' PIC port where E pin is connected DEFINE LCD_EBIT 3 ' port pin where E pin is connected DEFINE LCD_BITS 4 ' 4 bit mode DEFINE LCD_LINES 2 ' 2 LCD lines DEFINE LCD_COMMANDUS 2000 'delay between LCD commands DEFINE LCD_DATAUS 50 'delay between data sent adcon1=7:trisb=0:trisa=0:intcon2.7=0:osccon=$70 PAUSE 1000 repeta: high portb.0:LCDOUT $fe,1,$fe,2, "hello":pause 1000:goto repeta

Thanks skimask for the suggestion but unfortunately the output is still the same. Initially black boxes. On "release from reset", still black boxes. If I pull out the LCD Vdd - strange characters, plug it back in, I get character boxes filled with strange characters corresponding to the number of characters I output with LCDOUT and a blinking cursor at the end.

ADCON1 must be = $0F. If =7 AN9 is still analog.

If you still have problem copy ALL your CONFIG fuse settings here.

Quote:

Originally Posted by mister_e

ADCON1 must be = $0F. If =7 AN9 is still analog.

Which would likely account for the "0123456789" vs. "012301230" error noted in the 1st post.
Good call...

Eventually I moved the data lines on PORTC and voila, the LCD is displaying characters as it should. Thank you guys for the help.

Here is the working code:

Code:

' display a message on the lcd '--- defines DEFINE OSC 8 DEFINE LCD_DREG PORTC ' portb is the port used for data lines DEFINE LCD_DBIT 4 'the pin on port connected to LCD pin DB4 DEFINE LCD_RSREG PORTA 'pic port used for the RS line DEFINE LCD_RSBIT 4 ' port pin where RS pin is connected DEFINE LCD_EREG PORTB ' PIC port where E pin is connected DEFINE LCD_EBIT 3 ' port pin where E pin is connected DEFINE LCD_BITS 4 ' 4 bit mode DEFINE LCD_LINES 2 ' 2 LCD lines DEFINE LCD_COMMANDUS 2000 'delay between LCD commands DEFINE LCD_DATAUS 50 'delay between data sent '--- register configs adcon1=$0F ' all digital i/o trisb=0 ' portb all outputs trisa=0 'porta all outputs trisc=0 intcon2.7=0 ' enable pullups osccon=$70 ' oscilator configure '--- main program PAUSE 1000 ' pause to let the LCD initialise repeta: high portb.0 ' light led to see when main loop is running LCDOUT $fe,1 ' Clears LCD LCDOUT $fe,2, "hello" ' Returns to beginning of line 1 and writes "string" LCDOUT $fe, $C0, "world" ' line 2 pause 1000 ' pause to see it goto repeta ' do this forever