Post by thread:[PIC]: PIC to Graphic LCD problem!!

Friends, I have been working on a graphic display project for awhile now. I am using a display (128x128) with a T6963C controller in it. The problem is that I had it working with up to 255 bytes (maybe 256?) but started to mess with the code below. I didn't make a backup or print out the routine that worked (I know, extremely careless and dumb!!) and now I can't even get the darn thing to work at all. I didn't work on it for a month and forgot everything I did. Can somebody that is familiar with interfacing to a graphic lcd please help me out!! Most of my code is taken from Steve Lawthers information, beside the fact that he was very helpful in a few emails we exchanged. Basically I figured that since it didn't work anymore, I put the "led_on" routine to tell me where it stopped execution. It does not perform the "led_on" that comes after the addwf PCL,F command. I'm stumped (tired?!). The "led_on" sub-routine was used as an indicator, and it will be removed!! I checked everything else, looks OK. I think I'm missing something obvious. Anyways, if anybody could help me out I would appreciate it. Hell, if you can figure out a way so this code will work with a table larger than the 256 bytes,....... I'll send them either a tube of 10 new PIC16F877-20/P's or a brand new AND1391 ("128x128") graphic LCD (I have a few on-hand!). This code will NOT be used commercially, only private use (no I'm not trying to get you to do my work for me!!). I will eventually post it on my website once it gets completed. ;** // Data to be displayed on G.LCD!! // ** send_data: movf prog_counter,W ;Load "W" with "prog_counter"s value! addwf PCL,F goto led_on dt 0xff, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0xf8, 0x1f, 0xf8, 0xff, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0xfc, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0xbe, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0x9e, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0x1e, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0xdc, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 dt 0x07, 0xf8, 0xff, 0xff, 0x00, 0xaa, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 goto led_on ;--------------------------------------------------------------------------- --------------------- ; // Displays data on G.LCDs screen!!! // ; display_data: incf prog_counter,F movlw 0x80 ; 0x80 (d'128') movwf count_reg ;x 0x10 (d'16') ; go movlw 0x10 ;----------------- movwf data_count1 ; 2048 times!! (amount of bytes to send!!) ; cals1 movlw b'00001010' ;Set-up G.LCD for data. movwf porta ; nop bcf porta,3 ;/CE to be 0. ; call send_data movwf portb ;Send it to "PORTB" (OUTPUT)! incf prog_counter,F ;Increment "prog_counter" (deals with data table "dt" !!). call auto_write_status ;Test "STATUS" of G.LCD. decfsz data_count1,F ;Decrement "data_count". goto cals1 ; decfsz count_reg,F ;"count_reg"=1? goto go ;No,... keep going!! goto cals1 nop ;YES!!! Finished, continue on in program!! ; ; // Never used at this time!! // over: movlw 0xb2 ;Set-up G.LCD for "Data Auto Write Set". movwf shadow_reg ;Load contents of "W" into "shadow_reg". call write_command ;Set-up G.LCD to write a command. return ; ; ; Best regards, Steve Steven Kosmerchock Phoenix Arizona USA www.geocities.com/researchtriangle/lab/6584

Some things to check. Is the PCLATH set correctly when the send_data subroutine is called. Easy to verify with the simulator. Is the prog_counter value = 0 or 129 when the subroutine is called. If not, goto led_on will not execute. If the value of prog_counter is > 129 then the program will not work as intended. 256 byte table movlw High(TStart) movwf PCLATH movf Offset,W call DoTable ; restore PCLATH if need be and continue org 0x??FF ; 1 location before any boundary DoTable addwf PCL TStart retlw 0x00 ... retlw 0xFF > 256 byte table or any size table that crosses a boundary movlw High(TableStart) movwf PCLATH addwf Offset,W btfsc STATUS,C incf PCLATH movf Offset,W call DoTable ; restore PCLATH if need be and continue org 0x???? DoTable addwf PCL retlw 0x?? ... retlw 0x?? etc -- Best regards Tony http://www.picnpoke.com spam_OUTsalesTakeThisOuTpicnpoke.com

Just to say I'm also using Steve Lawthers code. I haven't got my additional code on me but if you would like to exchange ideas then let me know. I intend to do some graphics routines like circles, squares, dials and buttons, I just haven't had the time to do it all yet. I use a 240*64 Varitronix graphics screen with a T6963C controller. I have boundary checking written into my code which throws up an error if the table goes over a page boundary, but I don't have tables bigger than 256. I remember searching the archives and found something about handling crossing page boundaries. Pete If you wish to Email me at home (Fri->Sun) then do so at .....peterKILLspam@spam@trlperformance.com > {Original Message removed}