HD44780 custom characters help [pic code]

[Fletcher]

im trying to make some code which will load a hd44780 display with custom characters, i cant seem to get it to work. heres my routine:

CSTCHRS
BSF LCD_CTRL,RS				;SET RS LINE HIGH (DATA MODE)
CLRF COUNT1					;CLEAR COUNTER
CST1 MOVF COUNT1,W			;COUNT VALUE INTO W
CALL CSTC					;GET TABLE DATA
MOVWF TEMP1					;SAVE IT
SUBLW 0X04					;IS DATA = 04H
SKPNZ						;SKIP IF IT ISNT
GOTO CST1E					;EXIT IF IS
MOVF TEMP1,W				;GET SAVED DATA
CALL SENDDATA				;SEND DATA TO CGRAM
INCF COUNT1,F				;INC COUNTER BY ONE FOR NEXT BYTE OF DATA
GOTO CST1					;LOOP
CST1E BCF LCD_CTRL,RS		;COMMAND MODE
RETURN						;RETURN

CSTC
ADDWF PCL,F
DT 00H,00H,00H,00H,00H,00H,07H,1FH,00H,00H,00H,00H,00H,0FH,1FH,1FH,04H

can anyone give me any hints?

 

[Nigel Goodwin]

You don't appear to be sending a 'Set CGRAM' command?.

If you look on the EPE website at http://www.epemag.wimborne.co.uk they have an excellent LCD tutorial, which includes defining characters.

 

[techknow]

lookup table

i need an look up table for 4bit BCD ...i need an asm code ...not an another link to another site...

 

[williB]

4 bit ....16 values shouldent be that hard to work out.. why not create a thread of your own ..so we can go there when we want to see what yer up to. :wink: