LCD using ST7920 controller

[jjegarcia]

Hello,

It's nice to see this website has inscreased with the time. I used to refer in my University projects due to the simplicity and detailed information.

I still using pic's and in this case is not for MIDI but for music as usual.

In this particular I have bought a WINSTAR LCD 144x32 that comes with a ST7920 Controller.

I have managed to see the rom characters on the screen but I like to boost the graphics. I read the datasheets and I have supposed to write a code to store a dummy character in the user ram. But I cannot see it anywhere in the display.

Here is the relevent code (subroutines for wrting command or data seems to b ok as I managed to see the rom characters on the display):

start

CLRF PORTD

CLRF PORTH

MOVLW 0X00

MOVWF TRISH

MOVWF TRISD

MOVLW B'10000000'

MOVWF T0CON

CALL DELAY

MOVLW B'00111000' ;SET UP 8 BIT MODE-4, BASIC INST-2

CALL WRITE_DIS_COMMAND

MOVLW B'00111000' ;

CALL WRITE_DIS_COMMAND

MOVLW B'00001110' ;SWITCH LCD ON-2, CURSOR-1, BLINKING-0

CALL WRITE_DIS_COMMAND

MOVLW B'00000001' ;DISPLAY CLEAR

CALL WRITE_DIS_COMMAND

MOVLW B'00000110' ;ENTRY MODE: INCREASE-1,SHIFT-0

CALL WRITE_DIS_COMMAND

MOVLW B'01000000' ;address cgram 00

CALL WRITE_DIS_COMMAND

;load  chars to cgram

MOVLW 0X0A

CALL    WRITE_DIS_DATA

MOVLW 0X11

CALL    WRITE_DIS_DATA

MOVLW 0X0E

CALL    WRITE_DIS_DATA

MOVLW 0X04

CALL    WRITE_DIS_DATA

MOVLW 0X1F

CALL    WRITE_DIS_DATA

MOVLW 0X04

CALL    WRITE_DIS_DATA

MOVLW 0X0A

CALL    WRITE_DIS_DATA

MOVLW 0X11

CALL    WRITE_DIS_DATA

MOVLW B'10000000'

CALL WRITE_DIS_COMMAND

MOVLW B'00000001'

CALL WRITE_DIS_DATA

Unfortunatelly again I can see only the rom characters (happy face....ascii chars) but not anything else.

Any help will be must appreciated even some source code in your new c based operating system could help me to see what the hell I am doing wrong. 

Thanks in advance.....JG